The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: Gasket4450 on 08.12. 2013 13:24
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Hi Musky.
We have communicated before on this Forum under my post ' Refuses to Run ', which was traced to a dodgy magneto. All now fixed, thanks to Ken Targett at Brightspark . However, although the mag now sparks better than I've ever seen, my A7 engine is still very erratic, and won't run properly on both cylinders. It still sounds as though the timing is way out. Then I had a sudden flash of inspiration *idea* - I remembered that when I put the engine together some while ago, the only camshaft I had to hand was a brand new 357 !!! I remember thinking to myself at the time: " Must remember - different valve timing ". What I have, therefore, is everything set up for a 356 cam. When I happened across your figures in the above post, I realised that I had seen those figures somewhere before, at the back of Roy Bacon's book, the 'Bible'. Am I right in thinking that a 357 cam with valves set at degree timings for a 356 would cause the worst possible running imaginable ???
I suspect this may have been part of the starting problem from my original post in the first place ( ...although, of course, I now have a nicely refurbished magneto, so some good's come out of it ). I have a degree disc mounted on the crank with plasticine, and I presume I now need to adjust the valve timing by some judicial adjusting of the tappets - would that be correct ?
Can't believe I've been such a bonehead. Doh !! *doh*
Norman T
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HI Norman,
I'm not 100% sure I can follow your logic??
Regardless of which cam is fitted, just make sure the pinion timing marks are lined up when assembling the engine
The pinions are not different for 356 and 357 cams
(Beware if building an engine from parts as I believe longstroke pinions are marked differently) *????*
As stated because of the intermediate idler/ dynamo driving gear size the marks only line up every so often
(in engineering terms this is called a hunting tooth arrangement)
To check the valve timing in degrees theres a wider clearance specified, so as to avoid the opening and closing ramps
As the cams and followers wear these figures alter somewhat, so its difficult to be accurate
Thats where checking the "lobe centre " method comes into play,
Theres no need to bother with this unless racing the engine
I just noticed that my last post has been edited *ex* *ex* *ex*
The engine I was talking about was a 1920's J.A.Prestwich (J.A.P) and not some product from Japan *eek*
Regards
John
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Norman, theres no way of adjusting valve timing on an A10 without some custom engineering work such as a vernier pinion.
I believe you're talking about tappet clearances. Altering this makes small differences to valve timing & lift, but nothing thats going to affect running more than the adverse effect of wrong gaps.
A 357 works fine set at .008 intake and .010 exhaust.
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G'day Norman.
Please take note of both John & Briz's replies.
The two main culprits for uneven running are carb (bias) and timing.
Is yours a manual or auto advance? Have you checked your timing with a degree disc and strobe light. I recently checked a mates A7, he set it up with a fag paper and said it was spot on. I checked with the disc & strobe, timing at full advance was 55 deg instead of 35 deg.
You will need to attach the disc with a bit more than plasticine *eek*. Between the cush nut and spring.
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I recently checked a mates A7, he set it up with a fag paper and said it was spot on. I checked with the disc & strobe, timing at full advance was 55 deg instead of 35 deg.
My magneto timing took a big leap forward from the static setting, at higher revs, when the points pivot and the pivot hole were worn.
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My thanks to all for your advice. I think maybe I got the wrong end of the stick with the different figures quoted in Roy Bacon's book, and by yourself Muskrat. My engine is a standard 1959 iron head A7, with auto advance and retard. Everything that was worn I have replaced. I have timed it at 5/16" BTDC on the right hand cylinder, with points gap set to .012, and .002 when just about to open at 5/16 BTDC. Auto advance bolted up in fully advanced position ( the famous wooden-clothes-peg-in-the-arms dodge ) ( and yes, before you ask, I did take the wedges out before putting the timing cover back on !!! , although I do know of someone who didn't ).
I set the valve clearances according to the Haynes manual at 10 inlet and 16 exhaust, set when cold ( .....it's always cold 'cos it doesn't run . ha ha. ), although I will try 008 and 010 Briz, thanks.
The carb is a 376 monobloc, with 210 main, 25 pilot, and 106 needle jet, with new float needle kit, including one of those Viton tipped needles.
When I tried to fire it up, the left hand cylinder ran very sluggishly, the right didn't fire at all, just blew out some white smoke occasionally. Opening and closing the throttle made no difference to the engine speed whatsoever. It ran for about a minute, and then died. Same thing happened on each occasion, with the occasional cough from the right hand cylinder. When the engine died, the left hand exhaust was red hot, the right hand was tepid, so something must have been happening on the right. It sounded as though it had to be timing. That's why when I read the difference in degrees of rotation of the crank for the different camshafts I thought I had solved it. I was forgetting that since the cams have different profiles, valves will naturally be fully open and closed at different degrees of rotation of the crank. I have not tried it with a strobe because it will not run long enough to check it.
My thanks to John and Briz for your wise words. Unfortunately, it looks as though I will have to trailer it in to my local Brit bike garage, Roadstar Cycles at Dover, who are most helpful, and who know a thing or two about old Brit iron.
I don't like to admit defeat, especially when my last project, my 1960 A10, went from scratch without too many problems.
Thank goodness I still have one bike that works !!! I will keep at it, however, and report back in due course.
Thanks once again
Norman
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Hey Norm,
I did read it all,I have a A10 Plunger with 357 , S/R big valves, 7.25's, 389 experimenting with 25/30 idle, 250 main, 105 needle jet(which made a massive difference), and for now, it's running fine without even a (serious)thought of the valve timing but can't recall if you said you tried a different set of plugs....?
If not might be worth a go, even new ones can be dodgy...?
Also had to screw the idle mix a fair bit with jet changes (check for blockages too,which I had)
Just my thoughts, good luck, duTch
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Have you done a compression test, done with the throttle wide open? Have you swapped the leads, caps and plugs? What do the plugs look like?
It will end up being something really silly causing it. *conf*
Cheers
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Thanks for your views duTch. Sorry it went on a bit, but I was trying to give as full a picture as possible. I will try a different combination of main and needle jets, and see how we get on. Yes, I have tried swapping plug leads and caps. I use B6HS, and have also found they can be crap straight out of the box, so have half a dozen or so I can play with.
Musky, yes you are right, it will be something silly, which is why I am annoyed I can't find it. Plugs look OK, the left side is a dry dark grey colour, which would be right, I guess. The right hand plug appears spotless and brand new, and although it smells of petrol, it is bone dry. Have not tried a compression test as can't lay my hands on my old gauge at the moment ( although fingers in the plug holes work reasonably well....) ( ...somebody else's fingers, that is.....! ).
Do I remember reading somewhere in this splendid Forum that brand new Amal carbs have been known to contain swarf ?
Just a thought, as the one I have is straight out of the box. I do have a couple of old ones I can experiment with, so that should keep me out of mischief over the winter. Will get out the ultrasonic cleaner again, although I usually poke out the holes with a piece of lightweight fishing line where I can.
Thanks again. I will not give up, even if I have to rebuild the damned thing all over again !!!
Norman T
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90% of all carburation faults are due to the magneto, and most magneto faults are due to the carburettor ;)
The problem will be something so simple, you'll be laughing about it afterwords, as I know from recent experience. I spent half a day tracing problems with my bike (A10 plunger) after a recent rebuild. It would start fine, but as soon as I took it for a spin, it wouldn't accelerate, ran intermittently on one pot, and was a right pig. After about 5 hours of trying everything I could think of, I noticed that the air slide (choke) was down. As soon as I put the air lever back in its correct position, the bike started and ran perfectly.
A clean plug smelling of petrol - could it be flooding on that side?
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Hi shabashow, thanks for joining this saga.....!!
Yes, I tried altering the position of the air lever at all points of the operation, but without success, I'm afraid. When the choke slide was closed the engine died altogether. Since opening and closing the throttle didn't make a blind bit of difference, I wonder if maybe the needle is set too low, and is not clearing the needle jet sufficiently (....is it even the right needle, I wonder ? ). The Amal service sheets suggest a ' C ' needle for the 376, and a ' D ' for the 389, and either position 2 or 3........ does anybody have any alternative ideas please, just in case ?
I suppose the only good thing about this is that winter is upon us, and at least I won't be wasting time in the workshop when I could be out riding with my mates *smile*.
All the best
Norman
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Hiya Norm,
If, after switching plugs, leads, caps and cleaning pickups, brushes and slipring or trying different pickups-, doesn't change any, did you try re-timing it 180˚ around... ( L<->R )....?
(I think you can swap pickups over, 'cos I had two the same for a while- don't fit the same but for a test, be ok?)
If the situation reverses, it suggests maggie related, if not- suggsests valves or mechanical....?
Did you say if the points are opening the same both sides...?
Hard to understand how it can be fuel/carby related with a single carb...?
cheers, duTch
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Hello.
Red hot pipes are a sure sign of very retarded ignition.
raindodger
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I would concur with the retarded ignition timing prognosis. Last time I timed my bike, the magneto pinion must have slipped or moved (that's my excuse, and I'm sticking to it) when I put the timing cover on. It was also misfiring and not responsive to the throttle. It could be something as simple as that, as our engines aren't too complicated, and if your getting fuel and sparks, the next logical step it to ensure the sparks happen at the right time. Could you have timed the engine after tdc instead of before tdc?
You must be close to a solution, as there's only a few variables that can alter.
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did you try re-timing it 180˚
I just had a sudden dyslexic thought that my previous idea may be the same as switching leads, but that would need to be done also anyway
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including one of those Viton tipped needles
could be a factor, off the top of my head I can't remember which is right but some carbs have a fibre washer under the fuel filter housing on the float chamber and some don't, I'm thinking along the lines of float height, if yours has a fibre washer remove or fit one if it hasn't
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I would concur with the retarded ignition timing prognosis. Last time I timed my bike, the magneto pinion must have slipped or moved (that's my excuse, and I'm sticking to it) when I put the timing cover on. It was also misfiring and not responsive to the throttle. It could be something as simple as that, as our engines aren't too complicated, and if your getting fuel and sparks, the next logical step it to ensure the sparks happen at the right time. Could you have timed the engine after tdc instead of before tdc?
You must be close to a solution, as there's only a few variables that can alter.
Aha ! Now, here's a thing. When I tightened up the sleeved nut in the centre of the advance/retard mechanism, it didn't feel quite right, as though it was about to let go, or strip the thread, so I didn't do it up to 10,000 lbs of torque like you are supposed to.
I wonder if it is slipping on the armature spindle ??? The A/R unit was second hand when I got it, so I wonder if the spindle taper doesn't match the centre of the A/R gear ? I have had to lap two together in the past to get them to seat properly. Following on from that, does anybody know, therefore, if it is possible to buy a replacement nut ? I would think it is more likely to be the nut than the threads on the spindle. Maybe a spoonful of Bearing Fit would help ?
However, having thought about that, I think those nuts perform the job of a self-extracting puller on the A/R, so I suppose they must be conical in shape - does that mean I have to dismantle the A/R mechanism to get a new nut in ? *conf*.
I may revert to a manual mag that I have hidden away in the loft somewhere, as I see that second-hand A/R units are selling for prices in excess of £60 - £70 on Ebay UK. God knows what a new or refurbished one would cost.
including one of those Viton tipped needles
could be a factor, off the top of my head I can't remember which is right but some carbs have a fibre washer under the fuel filter housing on the float chamber and some don't, I'm thinking along the lines of float height, if yours has a fibre washer remove or fit one if it hasn't
Thanks Bill, good thinking. My fuel filter has no fibre washer under it, as I always thought they were meant to be that way to avoid altering the height of the float needle seat. However, I reckon that would certainly restrict the fuel supply, so may try one and see what happens !
Regards
Norman
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If I was a betting man I'd put some money on the timing having slipped. You could take a spark plug out and insert a straw or similar and see how much before (or after *conf*) tdc the points open out. There are settings for the fully advanced timing (11/32" for my Golden Flash) but I haven't seen any data for the 'normal' retarded timing. I'm sure that info will be buried in the vast archive of knowledge in this formum, or someone who's measured it will pipe up with the figures.
Of course, you could take the timing cover off and wedge it full advance to confirm. Not a big job, really, and shouldn't take much time.
I think taking the A/R unit apart would be difficult for me, as its riveted together. I sent mine off to get refurbished when I rebuilt my bike, I think it cost £45 or so, but that was a few years ago.
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someone who's measured it will pipe up with the figures.
Well I haven't measured it but do recall having a mild heart attack when strobe checking my timing on the Rocket God flash and saw it firing at TDC then remembering it was ticking over so was retarded, a blip of the throtlle returned heart beat to normal.
Not too precise folks but would think if using the straw or pencil down the hole method if points are opening at TDC retarded (both sides) it should be within range of running reasonable
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I'm a bit lazy, so the last few times I've tended to the timing (while sorting out the cam ring to even up the gap), I just pushed the points around to advance with my finger- seems to work ok
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Shabashow, the more I read, the more I believe you are right - it must be the timing slipping. After all, if there was something inherently wrong, the engine shouldn't run at all, should it ? I am thinking that if it runs as though the timing is way out, but does actually run, then it probably is the timing after all. I'll take the cover off and wedge the A/R in fully advanced and check, and let you know. Unfortunately won't be for a little while due to a little bit of a ' ....right wrist contacting ground at speed on unexpected wet leaves...... ' scenario ! A10 with dented headlight rim and shell, battered front mudguard, bent gear lever and footrest, and twisted forks. Hey, ho, nothing that can't be put right though. ( Could have happened to anybody, I told myself. Doesn't make you feel any better, though, does it ??? ).
Bill, thanks once again for your help. I have one of those little screw-in TDC gadgets, with a central sliding bar already marked off at 5/16 BTDC, so should be able to work from there. Would I be right in thinking that, as a rough guide, the points would be fully open at .012 thou at TDC ? I'm also beginning to suspect unequal cam ring shoulders, so something else to check.
Dutch, yes I have used the ' pushing with finger ' method in the past, so I know where you're coming from with that one. I'm obliged to you .
My thanks to all of you who have stayed with this tale of woe so far. I read nearly the entire ' Engine ' section of posts last week, so I know I am not the only one with starting problems (.......funny, my wife's been saying that for years......never knew what she meant 'till now....!!!!!).
Will report later, when I have two working hands again
Regards,
Norman
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Good afternoon Norman, been following your post with great interest but felt you were getting such good advice I'd keep stome . I'm , for my sins ,a confirmed "pencil down the plughole " timing type person ( for timing A10's only!! he added quickly ) and thought I'd chime in now ,hope you don't mind. With her set to 5/16" btdc the points should just be seperating ,hence the fag paper between the points tag that you hear mentioned (after checking that the points are open ing to 12 thou each side etc) and that should do it so you can do your strobing .\\\\\\\\\\\\if you are goingdown that road I'd recommend a mod by one of our gurus who elongated the fixing holes of the mag body ,so that it can be turned to adjust as per the strobe ,wonderful simple but effective mod ,think it was Orabanda who did it ,if not apologises to the rightful genius .That won't ofcourse help until shes running first so hence why I've suggested going back to basics then take it from there ,best of luck BobH. PS sorry to hear of your "off" happened to me a couple of years ago ,lowspeed but on gravel not to be recommended same sort of damage ,thou mostly hurt pride ,had an enormous brouse on by thigh ,had to tell the wife I'd banged it on the workbench or she'd have had me wrapped in bubblewrap everytime I wanted to go for a ride after!!
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G'day Norman. Those tdc tools give a false btdc reading due to the angle of the plug hole.
While you've got the spanners out remove the primary cover and make up a timing disc and pointer (mine is in 5 degree increments, see pic). Use the tdc tool to find tdc and mark the disc at the pointer. Mark the disc at 30 and 35 degrees. Use a timing light (strobe) with an external 12v power source. With the plugs out but earthed and timing light pick up connected to one, get a mate to kick like mad and watch your marks. With the auto advance left in the retard (wife recons I'm one) position it should spark at between 10 and 5 degrees before tdc. Swap to other lead and note any difference (cam ring wear).
The points will be fully open at about 20 degrees after tdc.
Cheers
Just saw Topdads post. Yes it was Orabanda's mod.
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But if we knew the angle of the plug-ole we could trig it ... ?
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Hello Bob,
Always pleased to see a new face on this long-running tale of misery. Thanks for your wise words. Yes, I had the same black bruising down the right leg, had to wear jogging bottoms with dressing gown for a couple of weeks so as to avoid rousing suspicion ( ....yup, I've got a bubble-wrap missus as well !!! ). Yes, seen that magneto mod, elongating the holes either side about 1/16" so the mag can be moved slightly when running, a bit like a manual A/R. I think at the end of the day I shall swap my re-con armature over into a spare manual mag which I have, which is in good nick.
Musky, does the angle of the plug hole make such a difference with the TDC gadget ? I reasoned that moving 5/16" sideways would probably equate to no more than 3/8" straight up anyway, so I would be safe. Perhaps I'll dig out my trusty pencil with the penknife marks which will stand upright, then ? I have one of SRM's ready-made discs, so will try that, as it appears to be the only trusty way to do it.
I will, however, start again from scratch. Just a thought - what does the oft-used phrase ".....timed 180 degrees out ...." mean ? If I am going back to lining up the timing marks on the pinions, can it only be done when the right hand cylinder is on TDC on compression ? Or does it not matter as long as crank, idler, and cam marks are all aligned ? Does the " 180 degrees out " refer to valve timing, or the position of the points in the end of the mag ? When setting my points, I have always used the right hand cylinder at 5/16" before TDC, and checked the points which are roughly in the 5 o'clock position, i.e. just before the heel moves on to the widest part of the cam, using a .002 feeler gauge. Can't afford a strobe at the moment, as just bought a Colourtune gizmo, in case my plugs are not performing under pressure ( ...bit like me, then... ). I had one donkey's years ago for my Ford Cortina ( ...remember Cortinas, some of you other old Greybeards out there ??? ), and I remember they were an excellent bit of kit.
Regards
Norman
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.timed 180 degrees out
Means the plug leads have been swapped around
Now just to perhaps input a bit of realism, the slope of the plug hole will make a difference - a small difference as will the backlash on all the gears that drive the magneto as will the tolerance allowed in the build of the A/R unit and the eye sight of the tuner and even the thickness of the pencil used to mark the stick stuck down into the cylinder.
all these small things can add up one way or another but in general BSA made bikes for Joe Bloggs to ride to work on all week and tune with his fag papers if he needed to while his wife made Sunday lunch, the bike would run if he was anywhere near right.
Some may point to he fact that most of the time any backlash will be taken up, this assumes we are in acceleration all if the time, not true most of the time while cruising we're on a steady throttle setting and the backlash will shift one one extreme to the other with every overrun
I have a notion the best tuners are to be seen track side blipping throttles and staring into the sky (you've seen them) but listening to the engine.
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Sorry to hear about your acrobatics, and hope all heals up ok. Sounds like a desperate attempt to get out of decorating the christmas tree ;) Too bad our machinery wasn't self healing (though I believe 'smart' plastics are in development which can self repair minor tears - hints of star trek science or witchcraft!) Anyway, back to topic - I raid our kitchen drawers for a wooden kebab stick to do my timing. I bend a couple of bits of wire into some small loops to keep the stick upright and put a pencil mark at the appropriate distances. I then put the bike in top gear and use the rear wheel to rotate the engine, going in the normal direction to get tdc, then rotate the wheel back to below the timing mark to take up any backlash, then slowly forward again to stop just when the mark is correct. Then I move the points hither and thither until the thinnest of fag papers just starts to release. Rizzla blue or silver are the thinnest, I think. If you want to check the timing of the other pot, repeat, but this time make sure the points are on the opposite side, i.e. when the other piston is firing. I think the lower HT lead goes to the right pot, but to be sure, disconnect the ht lead from the mag. If you see the brass bit in the slip ring, that HT lead is the one that will be sparking. I'm 99.99% confident that once you get the timing right (and make sure it doesn't slip again) you'll have a bike that'll start first (or at least second) kick.
John
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And in future don't listen to anyone about maggy overhauls until you've tried everything else. I've only had one done in 40 years.
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Great News, Great NEWS !!! *yeah* No, not the Second Coming, but nearly as good. I have been wielding the spanners as best I can, and have finally confirmed what I think we knew all along. Apart from taking the covers off ( and destroying my lovely oil-tight gasket work again .... ) to check timing marks, which were spot on, I removed the magneto, taking the auto advance retard unit off the end of the armature shaft. I removed the armature from the mag, and replaced the A/R unit on the shaft without the nut, and gave it a couple of sharp taps with a hide mallet to seat it on the taper. I turned the armature upside down in my hand, and what do you think happened.....? Yes, you guessed it, the A/R unit just dropped off the shaft. *eek*. Top marks to all of you who saw that one coming!!!
I tried it again to make sure, this time giving it several clouts with the ubiquitous mallet to seat it properly, and the same thing happened *problem*. Well, well, well, I thought. Obviously there was enough initial grab with the nut tightened up to stay in the correct position until the engine fired up, but then centrifugal force took over and moved the pinion on the shaft, altering the timing drastically.
So, it appears that although the A/R unit seemed to be secure when I tightened up the sleeve nut, it wasn't seating on the taper at all. I have attempted to lap them together with fine grinding paste, but to no avail. I have now junked the A/R unit, which was a
'Fleabay' special anyway, and will install a refurbed manual unit after the festivities.
Shabashow, was my ploy to get out of hanging flashing icicles from the roof that easy to see through, then ???? Always worked in the past. Thanks for your advice. I use the ' back wheel, gearbox in 4th ' method to rotate the engine by small amounts as you suggest, and I knew about seeing the brass contact on the slip ring through the pickup hole from the pages of this Forum, but I think we may be almost there now. Never thought about the kebab stick, though, brilliant idea.
Wilko, I guess you must have been lucky to have a mag last that long, and it was my fault for buying untried goods on Evilbay, the ' Bay of Fools ', as my local Brit bike shop proprietor calls it. In fairness, my mag did have a failed condenser, which would have caused me problems anyway, had it not been discovered, so paying out to have it put right was worthwhile in the long run.
Now, if only I can work out how to post pictures, I 'll put my pride and joy on for you all to see (....this thread has been running so long, some of you think I don't own a bike at all......!!! ), and maybe post a link to YouTube for the first successful firing up when it happens *beer* .
My thanks to all involved in this long-running saga ( ...been running longer than ' Home and Away' by now. )
Regards
Norman
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Don't you just love a happy ending!!! Really glad your persistence paid off and Johns final advice speaks volumes about these bikes of ours and poss a few roadside repairs without any fancy tools and has a nonsmoker found the only usefull purpose for fag paper ...between the points ,best wishes BobH.
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.timed 180 degrees out
Means the plug leads have been swapped around
Yes Bil, technically correct, but in this case I mean set the timing with the points 180˚ from 5 o'clock (@ ~ 11 o'clock surprise, surprise !!) / slip-ring brass contact on bottom side, so you'll be timing the LEFT side- same procedure.
This will then necessitate switching leads, either at the plugs or pickups.
Doesn't matter TDC left or right, they're the same ('cos they go up 'n down together)
I have the notion that the plugs are @ 45˚...?
...and yes, I use the " top gear, plugs out ' method too, with a thin metal rule and a zippy tie on the oil feed pipe,(or a short length of stainless or brass filler rod) and use my foot to do the wheel so I have two hands for the Alfoil which is about 1 thou (don't do fags)
cheers
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Great to hear you've found the root of your frustrations, Norm. *yeah*
Cheers
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Alfoil which is about 1 thou (don't do fags)
I don't do fags either Dutch
I managed to track down strips of 1 thou feeler gauge steel (comes in around foot lengths ), handy as you can cut an inch or so off and if (as inevitable) it gets bent or twisted discard and cut a new bit.
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Great News, Great NEWS !!! *yeah* No, not the Second Coming, but nearly as good.
Regards
Norman
Congrats, & always nice to read good news, thanks for posting.
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Glad you found the problem. Just a note on mag rebuilds, it is required sometimes. I had A10 that would not start when hot. Rebuilt mag, including condenser, fixed it.
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*yeah* So, perhaps it is finally time to draw a line under this one. Put the accursed beast on the drive yesterday, kicked it over twice, now fitted with manual advance/retard, and away she went....!!! Kept up a fast tickover for 5 minutes or so, so I am really pleased. Doesn't pull away under load properly yet, but not worried about that, as I can tinker with air lever/A/R lever, pilot screw, throttles stop screw, jet sizes, etc, etc, to my hearts content.
Sounds really good, with a sharp crackle to the exhaust.
My heartfelt thanks to all involved in this saga of doom !!!!!! Drinks are on me. *beer*
Norman
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Ah, the pleasure was so short-lived !!! With just 11 miles on the clock, I became aware of that horrible " spitting " noise coming from somewhere near the left hand exhaust port - yup, you guessed it, a blown head gasket *sad2*. Oh, well, back to the workshop. My fault for using a composite gasket I suppose, having tried everywhere for a solid copper job specifically for the A7. Tried all the usual outlets in UK:- Draganfly, SRM, C&D, Burton, Hawkshaw, Supreme, BriTi et al, but to no avail. " No, mate, I don't think they ever made one. " was the usual response. I suspect they did once make them, but there are none left any more.
Never mind, I have a job lot of A10 solid gaskets from a local autojumble, so one of those will be pressed into service. Ho, hum....... all the joys of head removal and replacement, along with my favourite job, the pushrods..... *problem*.
Thank Goodness for the famous pushrod comb.
Good job I've still got another running bike. Off out tomorrow with some mates for a day at the seaside in Sussex and a pub lunch. Roll on summer, eh ?
Stay Lucky, one and all
Norman
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CoppergasketsRus is the answer .
Lanni has them instock usually and if not cuts them in whatever standard thicknesss you want.
Postage on them is now a killer as they are too big for a US standard small package so buy the max weight ( 4, I think ) then flogg off the other 2 on evilbay or even the buy, swap, sell section of this site.
Every one always needs a head gasket or two.
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I'll just add my two pence worth on this subject, I've had problems with composite head gaskets although the present one is holding up fine. The method I used this time was to torque the head down and leave it overnight. I then torqued it down again and was surprised how much more it needed, shows they compress quite a bit.
I then had the engine running in the driveway while fiddling, tuning etc. and got it up to running temp. then took it for a short run of a few miles. After it cooled down I pulled the R/C off and re-torqued the head down, yes it went a bit more, not a lot but............. Fortunately as mine's an Ariel the R/C is easier to get on and off.
I do feel (a personal feeling not based on any fact) that if there's a bit of distortion anywhere a composite gasket might??? give a bit more leeway than a copper one. I did skim the head before fitting it but not the barrel so felt I might be giving myself the best chance.
I've only done around 1200 miles since it was fitted and only the last 300 giving it some real stick, but so far so good.
Colin
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Hi just a thought I had a new Amal (wassel ) carb and the needle kept dropping out giving the same
Symptoms as you .
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Trevor/Colin,
Thanks for your views on this one. I know the " Solid vs. Composite " discussion has run and run on this site, and I think I have read most of it. Yes, I did the gradual torqueing down, but the gasket was from an old set, and was obviously past its best. I should have bought new, but got caught in the adrenalin rush of : " Summer's coming, must get it finished.......". I don't normally skimp on parts, so don't know why I did this time. Another lesson learnt, then.
Incidentally, when I finished the A10, I had the same problem, but sorted with a solid gasket. 1200 miles like yourself now with no problems.
Thanks Wardleybob for your advice. I did have a problem with the Amal at first, where the new Viton tipped float needle was sticking up in the seat, rather than falling out, but another needle seemed to work, after I did the old
' clingfilm over the float chamber ' trick, as suggested by somebody on this Forum, so that I could see what was going wrong. A good wheeze, that.......I would probably never have discovered why I was suffering from fuel starvation otherwise !
Take care, and don't get carried away in the good weather UK riders..... I had a narrow escape yesterday going into a country lane right-hander about 10 mph too fast.
Norman
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Hi All.
Well, I know its been a while, but thought I ought to bring this sorry tale to a close once and for all. I've been out of action for quite a while with a broken wrist and thumb following a low-speed get-off on wet leaves on the A10 (....caught out again. My mates managed to avoid them, but at least they came back and picked me up, as good mates do.....). However, once I had two working hands again, I decided to replace the head gasket on the A7, finding it had blown clean through at front left, and I'm not surprised - the two front cylinder head bolts were not much more than finger tight! Something to be said for checking and re-torqueing head bolts, as various contributors have advised on this forum many times.
Anyway, while the head was off, I thought I would just check the timing, being at last able to measure exactly 5/16" from TDC, and guess what......? My points gap, which, of course, I would have sworn was spot on ( ...ahem ! ...), showed .003 and .004, not the requisite .012 I was expecting !!! This must have been the major contributing factor to all my troubles in the first place.
You were right, Musky, I should have used the degree disc from the start. We now have lift-off second or third kick every time, and it sounds wonderful. I'm very happy again, and very pleased I joined this community *smile*.
All the Best to one and all,
Norman
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G'day Norman.
Great to hear the pair of you are on the road again.
Cheers