The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: Hubie on 12.07. 2010 06:46
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Can anyone tell me a good place to get my crank balanced here in Victoria? Might just be the next step in fully sorting this A10 of mine. She runs great now but vibration kills the top end.
Cheers,
Dave.
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Are the engine plates good and tight? Is the head steady fitted properly?
David
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G'day Dave,
David took the words. My cafe developed a bad vibe around 3grand and a horrible knock under load. I had visions of big ends and or mains failing, till I noticed the rear top engine mount bolt missing and the lower rear bolt loose. Tightened the lower and got home with most of the vibe gone.
There was a bit of a discussion on balancing here a while back. 54% std, 65% racing, I went as high as 76% on my A7SS racer. Not that hard to do yourself but any motor shop that grinds cranks should be able to balance them.
Just had a look back. Josh posted this link. Very interesting. http://www.ajs-matchless.com/article_read.asp?id=26
Cheers
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(https://www.a7a10.net/forum/proxy.php?request=http%3A%2F%2Fwww.rbracing-rsr.com%2Fturbo%2Fbalance%2Fbalance_60.jpg&hash=75270543121bb115ece619b29d3786c4ae2470c3)
*lol*
Found that on the net recently, hits the nail on the head.
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Head steady is good as i just fitted new gaskets to the rocker boxes, will double check the engine plates, the front ones are fine after removing them when doing work on the dynamo. Gotta check the rear ones, but i suspect the balance factor on the motor is not as good as it could or should be.
Cheers,
Dave.
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G'day again Dave,
before stripping the motor down run a few tests first. Compression same in both hot & cold, timing same on both (use a strobe and degree wheel) and plug colour identical on both. Uneven running caused by one or more of the above will cause vibes.
The balance of the crank may need attention if you have pistons of greatly different weight to the originals or bored to 80 thou or more.
Try to eliminate everything else first.
Cheers
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Dave if you still want someone in Melbourne try Dyson Motorcycle Eng Ph 9390 2826. They balanced my brothers Triumph crank and he seems happy with their work.
Regards
Mark
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G'day Mark,
I rang Dyson and was very surprised at how helpful he was, and blown away with the price he quoted to balance the crank if I supply it to him sans crank cases.
I have gone over the engine plates and checked the everything else out that was suggested so I might have to order a full gasket set from SRM (unless someone knows where to get one cheaper!) and get back in touch with him.
Cheers,
Dave
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For gaskets, parts etc I have used DargAnFly, Kidderminster Motorcycles and TMS. And of course EBay.
Z
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Dave I got my gasket set from British Spares in NZ for $NZ120 or about $A100. I'm not sure what Modak charge but the're worth a call at least.
Regards
Mark
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G'day Dave,
I got my last set from Burton's for about $65AU landed. I use them as templates to make my own from gasket paper from Repco.
Cheers
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G'day all,
Have booked in to get the crank balanced at Dyson's, ordered a full gasket set from SRM ($59 landed) but am leaving out the belt drive dynamo kit (more pricey than i can afford right now) and the 21 gearbox sprocket. Thought it would be best so see what the result is like after the balancing is done. The barrels have had a hone run through them so it will be ready to be re assembled as soon as the crank is balanced which I should have back in about a week and a half. Looking forward to it!
Cheers,
Dave.
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So with a bit of luck you will be at the 6th BSA National Rally in Maitland on October 1-3 .
If so have a chat with Steve who has just put a belt primary on his A10, unbelievable difference.
I hope Trev( from OZ ) will be there as it is right in his back yard and I think Musky is coming along as well.
that is why we hold m so riders can do the touch feely thing which can't happen over the net.
All you with those smirky grins wipe em off right now. It is touchy feely the motorcycles, not the riders.
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G'day Dave,
what % balance factor are you getting done?
I have a SRM dyno kit in the cafe and a Lytedrive (Melbourne) kit in the '51. So much quieter and less maintenance than the chain.
I'll second the belt primary too. So smooooth, does away with the cush drive and with the sNorton Commical clutch no slip or drag. From Lytedrive as well for $1000AU. Save your pennies, both mods are well worth it.
Yes Trevor, sent my entry away earlier this week. Freshening the top end of the '51 for the trip. Removing the wife's seat to bodge up a rack.
I think Trev has to work that weekend, but I'm planning to swing by that way on the return trip.
Cheers
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G'day again,
I'm going for 60-62%. Has been recommended as the best factor for the bike. I will eventually get the dynamo belt drive kit but it is not urgent. As for my clutch, it works perfect with no slipping at all so no issues there. Will be very exited to get it back together and on the road. Will be working as far as the meet goes, but one day!!! it is my daily ride so the sooner the balance is done, the sooner i can reassemble it.
Cheers,
Dave.
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Good one Dave, should be sweet at highway speeds.
Don't rush it. Do it right, do it once.
Cheers
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MG, http://www.a7a10.net/forum/index.php/topic,2926.msg19719.html#msg19719
*lol*
muskrat > Don't rush it. Do it right, do it once.
good advice indeed, for lot's of things in life...
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I shall be doing it very carefully, with a micrometer and a maginfying glass!!!!
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Well I dropped the crank off at Dyson Motorcycle Engineering. The crank is going to be stripped, the sludge trap cleaned out and the bearing shells will also be checked before everything is rebalanced. I am very confident the man know's what he's doing. He immediately informed me that my pistons are not at all standard and that is would largely be the reason for the lack of a correct balance factor.
He says they are high quality italian jobs (numbered 71.5 on top from memory) and will obviously weigh them when doing the work. Am very much looking forward to hearing the results.
Cheers
Hubie
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It turns out my camshaft is a little worn so I am facing a regrind or perhaps a new one. My question is, can I get a regrind and not lose the peak on the cam lobes or do I buy a new one and will a road rocket cam fit in place of the original one?
Cheers
Hubie
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G'day Dave,
when they regrind cams they grind the base circle as well to give you your original timing and lift. As long as they don't have to take more than 30 thou off the base it should be ok. If they take more your followers may not drop far enough to reach the cam. It also alters the angle that your rockers meet the valves, so if it goes too far longer push rods are needed to get the angle back. Been there done that.
You would best be served with a 356 cam if it's your daily ride. A 357 or 334 will fit.
How are the followers? If the cam is worn they will be as well. You'd be looking at about $300AU to put new ones in (cam & followers).
Cheers
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Thanks mate,
Looks like I will get away with a regrind and a small cleanup of the followers. Taking the camshaft to a shop tomorrow to be checked out and then just waiting on the gasket set and the rebalance.
Cheers
Hubie
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A quick question too, the central pin that holds the inside cam followers in, is it a bash it out scenario or is there another way to get them out?
Cheers,
Dave.
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There's a screw with a 3/16" dia ball at the bottom of the tapped hole holding it in place which you will have to remove first, then tap it gently out.
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I cant see where this screw is. I've taken the ones out from the side but the pin in the centre is blank so to speak, nowhere to get purchase on it except to knock it out.
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it's on the top of the barrel flange, sometimes hard to see with layers of cylinder black coating it
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Found it lads! Alot of paint was covering it. Popped out no problems.
Cheers,
Dave.
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Yet another question to pose,
I'm taking the camshaft in to a cam place tomorrow. The man says he has a bsa camshaft for a twin but will need to compare it with mine to make sure it's for the A10. Would I be correct to assume that the cam profiles for the a10 and a65 are the same? Have just learned the cam is a 67-356.
Cheers,
Dave.
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Dave,
The early A65 had a mildish cam but from about 1964, I think, they were all fitted with the spitfire grind which is the same as the 357.
The A65 cam will not fit the A10 and vice versa.
If I had enough 357 cams I would fit them in everything I own!
Trev.
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Thanks Trev,
Do you happen to have the values for the 357 grind? I have heaps of meat on my camshaft so if I can grind it to that, I will!
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Dave,
The valve timing is 51-68-78-37 but I don't know the lift.
Maybe Musky can help here. Aren't new cams available?
Trev.
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Does this help?
http://atlanticgreen.com/images/356-357.jpg
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Hi Trev,
They are available but will be 200 bucks or a tad more with postage. If my cam can be reground it will cost me less than half that.
Cheers,
Dave.
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In addition, the top of my pistons are stamped 71.5. Can I safely assume from this that my barrels have been bored out 1.5mm or about 60 thou? Will be helpful if I am to purchase some new piston rings.
Cheers,
Dave.
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Or the compression's going to be really high :)
Actually as this is about vibration, has anyone ever had experience with the Ballancemaster rings. They are used on Harleys to smooth out the vibes and also to ballance truck wheels tailshafts clutches etc.
On the Harleys they machine a ring in the flywheel and they glue it in, what it has is a plastic ring containing an amount of mercury, from what I've read it makes quite a difference, and if I can get one a suitable size will try it in a 90deg A65, which are pretty smooth anyway, but it would be nice to get ballance shaft smooth without the ballance shaft and performance loss.
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Hello again Lads,
It seems after diagnosis that things with my crank are worse than thought. I have the earlier small journal crank and apparently on the timing side it is 20 thou undersize and as such, I'm told cannot go any further so it appears I may be on the lookout for a new crank. Questions that I would ask of all you more knowlegable folk out there are, can I have it built back up again? Can I work it so that a large journal crank will fit my cases and, does anyone have a good crank lying around to sell me???
I did receive my full gasket set and am having my camshaft checked at the moment. All is not lost and it will virtually be a new motor when finished.
Cheers again,
Dave.
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can I have it built back up again?
Dave,
The short answer is yes. My own crank was refurbished in exactly that way. It is a very common procedure.
John
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You can get it;-
plated
Flame sprayed
Welded.
As a general rule I go for plating on things like gearboxs & cam shafts
flame sprayed for cranks.
It is also advisable to get it nitrogen toughened as well, a very cheap bit of insurance ( $ 30.00 AUST )
In Sydney I usually get A1 Metalizing to my work but that is just because they are close & handy.
Usually the grinders will have a list of locals who can do the job for you
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The other option I have after speaking again with Brian Dyson this morning is simply to have a new timing side main bush made to the correct clearances with my crankpin. This should not be a problem I'm told given the bike is not going to be raced. The big end journals are also fine to be ground to -30.
Will be taking the crank case halves up to Dyson's next week for measuring up for that bush by the look of it and ordering a new drive side bearing from SRM, possibly along with a spitfire cam. Dyson engineering does not reccomend rebuilding crankshafts by building up the metal by spraying or welding. Has anyone had this done and got a fair amount of miles from their motor?
Slowly getting there...
Cheers,
Dave.
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Dave BSA supplied both big ends and timing side down to -.040". I'll add a scan out of the manual to give you the sizes.
If you are going to have a bush made then there is no need to go down another 10 thou, just get them to grind the journal until it cleans up and make the bush to suit, they may only have to grind 3 or 4 thou off it, you would end up with it somewhere around .025" undersize. This means it will have more life left in it for the future.
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agree with Brian, both my timing side bearings were purchased from C&D Autos who supply solid bushes of a size that allows you to just have the crank "cleaned up" and the bushes reamed to fit (others also will supply said bushes).
Had two bikes done this way, the shop that did them also don't advocate spraying metal
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Thanks a heap Brian, and everyone. I was beginning to think I was going to have to find a new crank or have one made - big dollars. All I want the bike to do is have the go it had when it was new and sit on 60 without rattling apart. I do most of my riding around town but there's the odd trip of 120-200 miles or so on the freeway and the reason I bought the A10 is that it should be perfectly capable of this.
Cheers,
Dave.
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After just reading the figures, my timing side journal is sitting on 1.335 which is 42thou under. If I can get it cleaned up and a custom bush made, hopefully it will be okay.
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You can go a lot further undersize than BSA recommends.
Like most things , they had to cover their back sides and their minimum figures assumes a moron at the bars with 12:1 pistons and a perchant for popping monos.
We had a club member with an A50 bought from Burma where it was hauling a chair.
The main was .13" undersize, yes that was not a typo it was 0.134" undersize,
there was a lump of steel can under all of the slippers which had been badly recast at least once.
I could go on but I think that you get the drift.
If you are going a long way undersize then look for low compression pistons.
You can go as low as 6:1 after which they get really difficult to tune.
Some where between 6:1 and 7:1 will give you a nice ride with enough poke not to run down by bowlers in Charades ( they traded in their Morries) but not enough to drag XR6's off at the lights, You will loose about 10 mph off top which will have you in the 80 mph range which is illegal most places in OZ in any case. The lower ratios will have a better chance of burning the new fuels remembering that e10 becomes mandatory next year which will be replaced with e15 a bit further down the road with the ultimate aim of nothing above e25 by 2050 when we will have to fit 15 gallon tanks to make it to the next servo.
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Thanks Trevor,
It seems that at only 2 thou under the reccomended minimum a cleanup on the timing side pin and a bush made to fit will do me fine. I can happily go to -30 on the big end journals and fit a new roller on the drive side and should then be able to happily cruise the freeway. My confidence in this rebuild is slowly growing!
Cheers,
Dave.
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Dave,
You can get the drive side main roller locally.
NF 206 from memory.
Trev.
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Thanks Trev,
Eastern Bearings aren't far from me (Ferntree Gully) and I'd bed they'd have it. I took my clutch centre and sliding plate into them and they had a sealed bearnig to suit that I was able to fit straight into the sliding plate without fuss. I had a 5mm gap between the back of the clutch centre and the inside diamter of the sliding plate hole.
Cheers,
Dave.
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I finally have all the parts I need after five missing pieces from a shipment and I have a new camshaft as well. Now the engineer who is doing my crank is away for the next week and a half! At least the end is now within reach! Can't wait to put it back together.
Cheers
Dave.
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Hubie don't forget to order your roller in C3 clearence, your bearing should read NF 206 C3. The C3 is the extra clearence you need because you are holding the outer race of the bearing in your case by interference fit (crushing it) a standard clearence (NF206) will run too tight when fitted, the C3 has extra clearence built into the bearing. *smile*
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Well all the bits went off to the engineer today so he should receive them in two days and the crank can finally be done. Then it's re assembly time. Looks like it'll get done within the next two to three weeks (finally) *smile*
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Wise words from RF.
Don't rush it. Has the bearing a steel or plastic cage? I just found a piece of plastic in my sump, looks like part of a cage!!!!!
Now all I have to do is heed my own advice !
Cheers
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Tis a steel bearing musky, will need to heat the cases to fit it in. Also pulled the heads of my RE super meteor last night to investigate low compression. One cylinder had a stuck second ring and the ring land broke extracting it. Looks like new pistons and rings and a +20 rebore for that bike!!
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Ok. My crank is ready to be picked up so I've been going over the manual so I don't stuff anything up when I reassemble the motor. I noticed in the manual that there is a shim between the drive side crank journal and main bearing but there was not one there when I pulled the motor apart. I do have four shims which were behind the drive side sprocket which I assume was there to eliminate end float. Anyone have thoughts on this?
Cheers,
Dave.
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G'day Mate,
thats how you adjust the end float of the crank. Before you put the rods on assemble the crank & cases. Set up a dial gauge on the crank and measure the end float, ( push or tap crank to one side then the other side to get measurement) subtract 2 thou" and thats how much shim you need behind the bearing on the crank. Careful taking the inner bearing back off to do so. I use a wrap around bearing puller set up ready then pour boiling water over bearing to get it off. Other methods on the forum. Try searching end float.
Cheers
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Thanks Musky,
I'd imagine that nothing has changed since I pulled the motor apart but I will measure it to make sure.
Cheers,
Dave
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Just a thought though, doesn't the shock absorber spring on the engine sprocket eliminate the end float?
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err, nope.
For the very same reason you can't help yourself out of a quick sand pit by grabbing your feet and pulling. *smile* *whistle*
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The cush assembly merely clamps the inner race to the crank webb. The inner race can slide in the outer as it is a roller bearing. You need to set the end float using the corect thickness shims which you can buy in a packet of varying thicknesses. Beware some manuals [haynes] show / describe shims on the timing side. THIS IS INCORRECT.
Good Luck
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In case you should need to remove the bearing Richard (Manosound) made an excellent tool to remove this...
http://www.a7a10.net/forum/index.php/topic,368.msg1717.html#msg1717
Good Luck... Let us know how you get on.
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Shall do chaps,
I will respectfully request that someone explain setting the end float to me in a manner that befits my lack of experience in doing so (like a dullard!) When I pulled the motor apart there were no shims on the crank, and four between the outside of the crank case and the sleeve on which the drive sprocket goes onto.
Cheers,
Dave.
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Hi Hubie
Muskrat put it down as it should be, but I know sometimes if you haven't done something before it's hard to follow.
Shims have to go between surfaces that do not move in relation to each other, in this case between the drive side crank web and the drive side bearing.
assemble the crank with the driveside bearing on it, fit it into the crankcases and bolt them up with at least four of the studs so its pulled up tight and square.
Set up a dial gauge at the driveside end of the crank.
Push the crank through the cases towards the timing side.
Adjust the dial gauge onto the driveside end of the crank.
now push the crank through to the driveside and record the reading on the dial gauge
If you have no dial gauge you will need to use a vernier, possible fixed sonmehow
whatever you use repeat the exercise a number of times and record the reading each time, if the readings vary (which they might but not by much) work out an average or take the most consistent which ever your happiest with.
Now you have the end float, when shimmed and assembled you need to aim to have a max of 3 thou so take 1 or two thou off your measured end float and fit this thickness of shimming between the bearing and the crank web (fewer thicker shims are better than many thin ones).
Can be a bit of a bind as you don't want to be removing the bearing more than necessary, so take time measuring.
I've done this twice once with a vernier and the last time with a dial gauge (much easier) managed to get 1.5 and 1 thou respectively
Good luck
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An easy way to do this without risking damaging a new bearing is to machine/ hone/ grind a few thou from the internal bore of the old bearing so it slides on/off the crank easily and use that as a dummy when you do your measuring. Of course you need to compare the thickness of the new and old bearings and compensate to be accurate. They normally are identical though.
The shims between your cush sleeve and spacer are there to align the primary chain.
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Hi Hubie,
The shims you found on the outside of the crankcases between sleeve and cush drive adaptor are to align the primary drive sprockets *ex* *ex*
Amen! to the other replies
HTH
John O R
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Well I am pulling my hair out already. when I picked up the crank, the custom made timing side bush was sitting on the journal. I heated the case and fitted the bearing into it and now the crank will not go into the bush. Now what the hell do I do??? ???? ???? ????
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Thats what is meant to happen Hubie. You now have to find a engineering joint to line bore the bush to the opposing side, get them to give it .001" to .0015" clearance.
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*smile* Welcome to BSA rebuilding.
You must have read about line boring ? Yep, been there. The bush has now to be reamed or line bored to match the drive side true and square,
Same as getting married, lots of things they don't tell you. *eek*
Cheers
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It has been delivered to an appropriate workshop for just that purpose. Hopefully, that will be the last of the difficult things to do, the rest I should be able to do in the mancave *smile*
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Hi all,
Picked up the engine this morning. Everything is starting to look nice and peachy now. I have ordered a shim pack (need 25 thou) and then it will be assembly time.
Cheers,
Dave.
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Good one Dave, not long now.
Crickey 25 sounds a lot, most I've had is 12. Monday cases, Friday crank I suppose. *smile*
Cheers
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Dont forget that when the crank is in and the crankcases bolted up, give it a turn and check the end float before you go any further.
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My plan is to fit the shim/s, bolt the cases together and re check the end float, aiming for about 2 thou clearance (book says 5 max) before applying the jointing compound to the faces and getting in the re assembly in ernest.
Cheers,
Dave.
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I've re measured (4 times) the end float of the crank and found it to be 19 thou. So the shim size I am looking for is 17.5-18 thou. Dropping into a mates tomorrow to collect a flying flea and might find shims to suit, otherwise I have some on the way.
Cheers,
Dave.
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Dave... Don't forget to add another couple of thou to compensate for the jointing compound! Good Luck mate your nearly there!
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HI Dave - my book says 3 thou max
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Dave,
What the hell are you going to do with a Flying Flea?
I have got one in my shed which I have had since about 1967. It cost all of $6 when I got it!
I rode it to work for a while but it was too slow so I bought my first Flash which is the one I am currently riding.
Trev.
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Hi Trev,
A mate who collects RE two strokes has bought it. I am just holding it for him until he gets back from serving in east timor. Bill, I'm aiming for 1-1.5thou end float.
Cheers,
Dave.
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Well it runs. Very rough so far though. More compression on the left than the right so I will re check the tappet clearances and have to double check the timing as well. The kick starter gets stuck every now and then also so a few things to sort out before it runs the way it should. any advice would be appreciated.
Cheers,
Hubie.
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Have now checked compression and both are the same. One cylinder does not seem to be firing very well. The left side is alot hotter than the right. Have swapped plugs and leads and also re timed the bike. I am starting to think it is cam timing but I did line up all the timing marks when I assembled the motor. I wonder if the new cam has anything to do with it? Tis the same 356 cam as what was in it.
Any advice would be much appreciated.
Thanks,
Dave.
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G'day Dave,
sounds like the timing is uneven. Re check the timing on both cylinders. You might find that one is firing at 5/16" and the other at 3/8". This is due to wear on the cam ring (magneto). The best way to check is with a strobe and degree wheel on the crank. If it's only a couple of degrees out split the difference. Say one side at 35 the other at 33 isn't too bad, but.
If that checks out it might be induction bias. Both plugs should be the same colour. You can get a anti-bias gasket to cant the carb towards the weak cylinder to fix that.
Don't think it would be cam timing as both cylinders would be out. But then again I had a cam reground once and the inlets were 5 degrees out and the exhaust 15 degrees out. Easy enough to check with a degree wheel on the crank that they open and close at the right times
Kickstarter sticking (they all do that sir). Wear in the bushes/shaft and or pinion.
How did you go with the end float ?
Cheers
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Hi Musky,
I've re timed the bike three times now and I am not convinced that ignition timing is the issue. Once the bike is running, opening the throttle delivers next to no response. It is very flat, like the valves are not opening and closing when they should. I am certain that I lined up all the dots on the pinion and idlers but there is a new camshaft in there as well. Going to have to pull off the inner cover and just see how things go I suppose.
Cheers,
Dave.
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Hi Dave,
Just thought or 3!!
Did you wedge the auto advance in the fully advanced position before timing the engine?
Also check that the pushrods are seated properly in the rockers, Are all the tappet adjusters at about the same adjustment, if one is way different to the others there may be a pushrod misplaced
Finally have you fresh petrol in the tank??
HTH
John O R
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HI John,
Advance unit was properly set, pushrods are all seated (used a tiny mirror to check they were all in the cups - although one was dislodged originally so I hope to christ i haven't bent a pushrod or a valve) petrol is the same as it was in the tank from two months ago.
Cheers,
Dave.
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I should add compression is even on both sides, one in firing well the other not so. Have swapped plugs and leads and that is not the issue either. I'll get there eventually!
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Very good mate who just closed up shop after over 40 years popped over today, answer is a bent valve. I don't have the tools to remove so he's taken the bike away for me and will sort it out and fine tune everything. Shouldn't be too long.
Cheers
Hubie
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Well lads,
The valves are fine but after checking, my pistons sit about 1/4 below the lip of the barrels at TDC. This should not be the case as it's only giving 90-95 PSI per cylinder. Looks like I have to find a new pair of pistons and rings. They are oversize at 71.5mm anyone who knows a good place to get them would be much appreciated. Also, the height of the piston from the top of the piston to the gudgeon pin if anyone has one lying around would be great.
Cheers,
Dave.
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Just got back from having a look at it,
pistons sit down about 11mm too low in the bore. Has be wondering if they might be A65 pistons instead of A10 ones. They are GPM and are 71.5mm. No wonder the bike had no go heading above 50mph. The top of the piston to the top of the gudgeon pin is 30mm and I need 11mm more than that.
Cheers,
Dave.
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I have to confess to being a little baffled by all this. I would have thought you would have noticed this when you stripped and rebuilt the engine? Didn't you turn it over after fitting the barrels and before fitting the head? It's a natural thing to do to check that it all turns and has not bound up. How did you time the ignition, how did you find TDC?
I would make sure you have the right crank and con rods before you go any further. *conf*
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Thanks Andy,
I've gone as far as I can as I had the whole thing up and running. I should have checked it before I put the head on but as the machine was running before I had the crank rebuilt and I timed it before then anyway and the timing tool I marked up was lining up exactly the same as before so assumption has made an ass out of me. The conrod numbers are G7270R3R2R which I don't recognise so maybe someone could help me if they recognise this number and also to tell me the stock conrod length for a small journal crank?
Cheers,
Dave
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G'day Dave,
the plot thickens ! Is your crank a large or small journal ? You might have 6" A50/65 rods in there instead of 6 1/2" A10 rods if it's a LJ. Or A7 rods if it's a SJ.
Cheers
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Hi Musky,
It's a small journal crank. The bike is coming back home tomorrow so I will get a better chance to check the numbers and measure the rods. I think I am now on the lookout for some small journal rods. If anyone here is able to help with that, I would be over the moon!
Cheers,
Dave.
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Dave,
It looks like someone has put A7 rods in your engine. Or an A7 crank.
Maybe you need to have a quiet conversation with the bloke who sold you the bike.
Preferably with a big stick in your fist.
Trev.
Surprising that it ran at all.
A mate bought a Flash years ago with the same. He couldn't get it to start.
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Dave,
The rod number you quoted would be 67-270 which is an A10 small journal rod.
Seems like you definitely have an A7 crank.
Get that big waddy and have that conversation!
Trev.
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HI Dave,
Buggershitnf**k *ex* *eek* *eek*
What a shedfull of bad luck ????
All this will now render the balancing you had done to nought *sad2*
Better luck for 2011
Regards
John O R
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Hi all,
It does seem that I have got an A7 crankshaft. Rebalanced to 65% and new big ends all ready to go. I wonder if someone here needs one? Now I have to find an a10 crank!
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G'day Dave,
sounds like you were the first mouse. Bugga.
So was that the original crank in it since you have had the bike ? The balance would be out the window if done with A10 rods & pistons.
Look for a LJ crank & rods. 230561776736 & 170563799964 I'd love a set of those rods or these http://www.mapcycle.com/ProductDesc.aspx?code=MAP7078/A&type=0&eq=&desc=CONROD%2f-A10-%28LATE%29-6.5--EXTRUDED%2fBILLET&key=it
I picked up a crank & rods not long back as I plan on punching the '51 up to 650. I'm not sure but I might have a SJ crank somewhere, will look on weekend.
Cheers
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Thanks Musky. As long as there's a proper sized crank out there for me somewhere I'll be overjoyed! I should at least get a couple of dollars for the one that I have too as apparently a7 cranks are even harder to find. I shall await further responses. It is the same crank since I bought the bike. Buggered if I know how it ran at all.
Cheers,
Dave.
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How about popping some a7 barrels on - is this possible? seems you have such a nice bottom end now. Really sorry to hear this story my goodness I am amased you are still with us - I would have probably topped myself.
I bought a similar pack of lies and have spent the last year trying to replace the junk that was put inside the casings!
PS you must be onto a winner luck wise, as this was enough to last 2 life times.
Keep at it, you will get there!!
Regards
Nigel
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Nigel,
Even fitting A7 barrels will not fix this mess as the rods are too long and the pistons too fat.
Trev.
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Thanks Chaps,
I have really felt like i've been given a kick in the guts by mr murphy but there is no point just parking it and doing nothing. I want a working bike and I know how good it will be once it is done. I've spoken with the president of the BSA owners club down here in Victoria and he's been nice enough to see what he can do. Also the excellent engineer who did the crank work, Brian Dyson is heading over the Adelaide after christmas and is stopping in on a friend who runs a bike shop there who has stacks of BSA stuff and might be able to work out some sort of swap involving my new crank. Muskrat is being kind enough to look for a crank this weekend in his shed and there is a BJ crank in the US on ebay at the moment (hands off!) that I have my eyes on. Then I have to source rods as well.
The problem is easily fixed but very expensive so I am going to have to save my pennies for a while. On a more positive note, I got my Super Meteor (blasphemy I know!) up and running last night and it is ready to bed the rings in and looks grand.
Thanks for all your advice and support chaps - I may have given up by now without it!
Cheers,
Dave.
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Hello Dave,
There is a chap here in Germany with a lot of A10 bits, if nothing turns up let me know and I will see if he has got something suitable.
PS as the first buy was a bag of **** I decided to by a working 61 A10 and guess what - its next in the workshop!
Good luck
Nigel
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G'day all,
My present from Terry Kennedy arrived in the mail yesterday (Thanks Terry!). I now have an excellent quality LJ crank, NOS rods, nuts, bolts and washers plus a better oil pump than the one I had. Just have to save up for the top end stuff (valves and guides) and a few other odds and ends and the old girl will live again.
Cheers,
Dave.
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Good on ya Dave
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Well I have finally dropped off my new crankshaft for regrinding and balancing. The timing side shaft is on -10 and perfectly round so it stays as is, the big end journals are on standard but a tiny bit out of round so I am going to minus 10. Slowly, it's all starting to come together and I still have my SJ crank for sale (A7) if anyone is interested.
Cheers,
Hubie
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Cases are back together now so the motor can go into the frame. Waiting on some odds and ends to arrive from Draganfly and then the whole thing can be completed. Going to a 21 tooth sprocket. Really must thank Terry K for the crank. The driving and timing side shafts look so good you could be forgiven for thinking they've never been used!
It's all slowly coming together now. Just need a buyer for my very early short stroke A7 crank!
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Hubie,
Why don't you build an A7 around the crank?
Trev.
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Trev,
If I had the dough and a withrdawn threat of divorce from the petticoat government over the prospect of a fourth bike entering my garage, I would!
Cheers
Dave.
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Well the bottom end is back in the frame now and I finally have my new valves and guides so I can complete the rebuild. Having not done valve replacement before, I can see that one pair are slightly smaller in diameter than the other pair. Anyone able to tell me which are inlet and exhaust? My guess would be the exhaust ones would be the slightly bigger.
Cheers,
Hubie
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G'day Hubie,
inlet are larger than exhaust. After the guides are put in give the valves a quick lap. If they don't make contact all the way round the seats will need to be re-cut. Most auto engineers can do that.
Cheers
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Hi Hubie
Muskrat's correct, I kind of thought along your lines until I rebuilt the Flash, then I came to the conclusion that if what gets sucked in gets burnt and converted to energy there would be less of it to get chucked out.
not so sure now about that stuff we got at school about not being able to destroy matter just change it, might help explain the big bang thing though ( all be it in reverse)
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Hubie,
When you replace guides it is advisable to have the seats cut as the guides may be slightly different to the old ones.
Engineering shops don't seem to lap valves these days. Grind the valves, cut the seats and vacuum test being the norm.
Trev.
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Thanks Trev. I have a place here that can do that for me. I do want to get this right as the entire motor will be new this way and I should get alot of trouble free and fun riding out of it.
Cheers,
Hubie
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Bit more progress on the bike last night. Got the 21 gearbox sprocket on, had enough play in the rear wheel alignment that I did not have to lengthen the rear chain either. Whacked the clutch and primary on first to adjust my primary chain tension (much easier to do without the inner cover in the way!) and I plan on putting the timing side together tonight, Primary tomorrow. Going to a mate's early next week to do the cylinder head and I can then do my final adjustments and get her up and running. Slowly she goes.
Cheers,
Hubie.
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More progress made tonight. Timing side back together and dynamo in. Magneto will go on tomorrow followed by the primary side. Getting nearer!
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Hubie,
Time the magneto before you put the head back on.
Trev.
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That's the plan Trev, can't get much more accurate than using a vernier with the head off. I just need to know how to tell without the head on which side is on compression. My guess would be looking at the pushrods, the ones low down on the cam would indicate the valves being closed. Am I on the right track?
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I'm not sure how much you have stripped down but if the timing case covers are off then IIRC when the timing marks line up the timingside cylinder is on compression TDC.
I stand to be corrected though my memory being what it is.
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Hubie,
It doesn't really matter which side you time on as the only difference will be which lead goes to which cylinder.
Conventionally the rear pick-up feeds the left cylinder.
Having said that, you should check both sides and ensure that both fire at exactly the same degree of advance.
Use a degree disc after you find TDC.
If there is any discrepancy between cylinders, a little work on the cam ring with a fine grinding stone will fix it.
Trev.
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Spent the day with Clive Carter and we did a cylinder head on a GN 250 plus installed the new valves and guides in the BSA head along with lapping them in. The components now only need assembling and the bike will be running soon!
The end is in sight!!
Cheers,
Hubie.
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Barrels are now on and I've made some new inner primary gaskets. With a bit more time, the primary will be on and I'll be almost there. Other work keeps intervening and preventing me from finishing the bike in one stint but at least I have two others to ride.
Cheers,
Hubie
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I know the feeling Hubie
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Hi all,
Just reading up on setting the timing with the head off, supposed to be the best way to get your btdc mark exact as you can, and have noticed in the haynes manual that there are flat top pistons in place. Mine are not and I can only assume must be high compression jobs. Is anyone able to confirm this?
Also, i have a four spring clutch that has the pushrod and outer pressure plate as one item. I have adjusted the spring screws so that the top of the thread is about level with the top of the screw heads and the clutch looks to be working well. Does anyone have any tips on getting this type of clutch fettled just right?
Cheers,
Hubie
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G'day Hubie,
the domed pistons will not make any difference to your BTDC measurement. Flat tops are about 7.25:1 yours may be 8, are there any #'s on them?
With the clutch make sure the pressure plate lifts square. That is, with the lever pulled in (use a cable tie to hold it) turn the motor over and use a dial or scribe and adjust the springs so it turns true.
Cheers
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Thanks mate,
All done up and the pistons appear to be 8.5:1
The head is now on so all i need to do is put the rocker box and carb, exhausts on and give it a kick
Cheers,
Dave.
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I finished putting her together last night. It's so darn good to see her all in one piece again, hasn't been that since last october. I didn't run the motor though as it was near 11.30pm here so I'll fire her up this morning. Have been constantly kicking it over without fuel or spark to get some oil through the motor first. I have checked, and re checked and re checked the timing and I am confident it will start fairly easily.
Fingers crossed boys!
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It's alive!!! three kicks and it fired straight into life and it feels awesome! After the smoke cleared, I have a nice plume of black smoke even with the pilot air screw all the way out so I think I need a much leaner pilot jet but other than that I think it's spot on!
Thanks to all who have provided advice and encouragement throughout this whole ordeal. I will have her on the road very soon!
Cheers,
Dave.
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Great news Dave, its good that it started easily, that usually means that all is well. Well done !
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Does anyone have a late model concentric mk1 on their flash? Mine has no pilot jet, a 106 needle jet (with the two small holes in the side) an number 3 slide and a 240 main jet. I've put it all back together and put the needle clip in the top notch to see if it will help with the richness and now I can't get it to fire up. I did tickle the carb again but I don't think it's flooded.
Cheers,
Dave.
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Brand new plugs giving no spark. Changed to some spares, bike revved right up, I had to shut the fuel off as the idle stop was way to high. It now runs a treat with no smoke. Very very smooth with lots of power and a clean idle. Only thing I had to change was dropping the needle down one notch.
Cheers,
Hubie.
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Great to hear Hubie, recon she'll be a treat to ride now. *yeah*
*beer*
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wink2 wink2 wink2
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Good on you Dave glad its running it wont be long and you'll be flying down the highway. It will be worth the wait and effort. cheers Terry
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Well done - these plugs are getting to be an issue
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Hi Hubie,
Well done *smile* *smile* *smile*
I think this must be the longest thread on the forum ????
The concentric carb does not always have a removable pilot jet ( thats a long story)
in behind the air screw theres a brass bush pressed in with a tiny (0.015 or so) hole in it
On a lot of bikes this pilot jet is too small, I have found it best to ream this out to 0.020in (0.5mm)
with a jet drill. this will give better response from ow down
It is quite common for this jet to be gummed up if the carb has been lying idle for a period of time *sad2*
I think the 240 main Jet will be too small for a 650?? the Haynes (liar) book says 270 for an A7 and 250 for A10 which doesnt make sense ???? ????
I have a Mikuni on my SR so I cant check that for you!!
HTH
John O R
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240 is correct for a Flash John ( in a 389 monoblock)
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Thanks for all the kind words lads,
I did some snooping around and had a chat with a friend whose full time job is to restore bikes (british only) and he's told me that the 240 main jet will be fine in the carb. It will be a little while before I get the throttle open far enough to check that jet while she's running in. The plugs I bought were champion l82c plugs and only lasted for two runs around the block while I was fettling the carb. The ones in it now are champion l86c's.
I might have to invest in some ngk plugs I think. That crank you sold me is a cracker Terry and I also used the oil pump you supplied as well. I kicked the bike over for quite a long time before putting the carb and plugs on as I didn't want the bike running for ages without oil going to the big end. Last time it was over two minutes before I saw oil returning to the tank. This time it was about five seconds.
This is indeed a very long thread so I may start a new one for when she's registered and and being run in. Some video will make its way to youtube soon.
Cheers,
Dave.
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With the plugs Hubie your Champions are equivalent to a NGK B6HS which is right for your bike. You can go one range colder to a B7HS. With NGK plugs the higher the number the colder the plug.
I run B7HS in all my BSA twins but I live in the country so all my riding is at highway speeds. If I lived in a city or did more rallies at slower speeds etc I would use B6HS, they are less prone to fouling than the B7HS's
You can also use BP6HS or BP7HS which are the same except they have protuding tips. There have been millions of articles written about the pro's and con's of protuding tip plugs so I wont go into that area.
I have a concentric on my plunger Flash, it has the needle in the middle groove and a 240 main jet. I modified mine so it has a changeable pilot jet but thats another story.
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I've taken her for a quick run around the block since fettling the carb. No smoke, no hesitiation. Just very smooth, it goes fantastic and starts well. Cant wait to see what she's like when she's run in. Only a little throttle opening produces some very rapid movement. I just love these BSA's *respect*
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Its no surprise that your Champion plugs fouled up so quickly. Thanks to our modern "petrol" if the plugs get wet from a rich mixture and cold engine scenario they wont work. I had this on my own flash. I went to the hotter NGK B6 and the problem stopped. The B7's were prone to failure a few seconds after start up while the engine was warming up. You have 8.5:1 compression, you might need B7's it depends how it runs.
People often think that the new plugs are faulty, they probably aren't until wetted then its game over.
Good thread BTW. well done.
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I had been told that you should run the coldest plug you can without fouling. I run B7ES in the '51 (alloy head) and B8ES looking at B9ES for the cafe.
I once had a '69 Monty GPMX360 and used a 5 to warm up then changed to a 9 to race.
Hubie, I can see your smile from here.
Cheers
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G'day all, I have uploaded a quick and average quality video of the flash up and running finally. Sorry for the quality but there will be more and better footage to come. Enjoy!
http://www.youtube.com/watch?v=dFuC7SP1Iq4
Dave.
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Good on ya Dave enjoy it. I look forward to riding my old 1947 A7 everyday I never get sick of it. I just waste fuel riding until the sun goes down.
cheers Terry