The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 1946-1950 => Topic started by: fffcycles on 17.02. 2021 19:59
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Hello Folks,
Now that I found a new cam for this from Feked, gasket set from Draganfly and the correct bushes from Baxter's I have started on the engine assembly this morning. I have some questions on a few things and would appreciate some guidance on a couple of points.
Got the rivets I needed and replaced the gearbox oil seal, no problem; but is there no drive side oil seal on the crankshaft ? All my Nortons have them and many others I have done, though not the Ariels, so need to confirm this one.
For this age of machine I understand the castellated nuts with split pins but since the PO put this together I will open these up and check shells and clearance again. Any tips on the crank shells and experience with the split pins?
Frank
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No seal on the crankshaft, Frank. Just a slinger between the bearing outer race and the case.
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Frank, All engines before 1953 Model Year do not have a crank oilseal.
These engines have an oil slinger outboard of the main bearing, clamped against the inner race by the cush drive sleeve. it's a simple flat washer with a pressed edge Part 67 349 listed as a bearing shim. Offer into the bare case before fitting the bearing (early ball race type) or the outer race used in the later demountable roller bearing type design. These bearings are different sizes and do not interchange.
The drive sleeve on these pre-oilseal early engines is a close fit to the crankcase, and most have a scroll cut onto the outer edge, others are reported to be plain. Trev nailed it that bit quicker.
All is detailed in Service Sheet 208, here the A7 references are mainly for your early engine, which confuses owners of the later redesigned versions of the A7 & A10. Service Sheet 207 details crankshaft journal dimensions which are the same for all small journal split conrod type cranks.
WARNING!!!! No if's or buts, the crank needs the blanking plugs removed and the narrow oilway between the big end journals cleared out, this so called sludge trap really needs a clinical standard excavation. This is a known weakness in drive side big end lubrication, obstruction of oil flow here is the cause of many catastrophic engine failures. Big end bolts for this Longstroke engine are unique and not readily obtainable, so preserve them if you can.
Most aspects of assembly are the same as for the later engine, all have been featured on the Forum and it is a matter of having a good dig into previous posts.
Swarfy.
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Hello Swarfcut,
Got out my bulletins looked up some of the details and testing crankshaft end float today.
I always clean out sludge traps on all engines I rebuild and this one was plugged on the gear side really badly. Explains why the PO had to weld up the case from a thrown rod but all is good now.
Frank
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It is always the way of rebuilds to go sideways I say. Had the sludge plugs removed by welding on 1/2"nuts, torqued them out with an impact gun, cleaned up everything then went to install new LS plugs I had ordered but these are too small it would appear. I have ordered a set of the large plugs but have to wonder why these holes/plugs are different (7/8" ?) than that listed in the parts catalog. Another week or so transit for the latest order from Drags, Oh Well, better get on with the '68 Thunderbolt or Trident clutch while I wait.
Frank
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Frank. Reckoning all small journal cranks have the same plugs, just measured a 1949 L/S (steel rods) plug. Its the same as the later small journal alloy rod crank type, plug is part 65 615, same plug both sides.
Searching the L/S parts list on the Forum Literature section, can't find a plug listed for the L/S crank. Having said that, the early parts books are an all in one format, so not easy to navigate.
So, another conundrum that no one could have seen coming. Evidence of previous attempts to remove the plugs, wrecking the threads and an oversize plug to suit? Who knows?
Swarfy.
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Thanks Swarfy,
I did find 65 615 in the parts catalog listed as “crank complete” so something wrong in that. Also looked at what I had ordered and Feked had it marked as 0615 and my presumption this might be correct has led me astray? I have ordered the hex type and a pair of straight slot type for this next try and will see what fits in correctly.
Frank
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Frank Feked list 65 615 Crankshaft Oil Hole Grub Screw as 5/8"/ 16mm, I've measured the crank thread ID at 15mm so that's the one for my small journal L/S crank. Crank Oilway Plug is what it is.
Part 67 615 is indeed a complete crank listed just 3 lines above in my parts book.
The larger 7/8" plug is used on the later big journal cranks, A10 and A50/A65. Big Journal plugs are somewhat different. One has a locating tit for the sludge tube, other plug is plain. All Alloy Rod A7 cranks use the same smaller plug as do small journal A10. I assumed you had ordered correctly supplied plugs that did not fit because the holes in the crank web were not as expected.
Thread size for the smaller plugs is 5/8" X 20 TPI. Use the search bar above, look under "Sludge trap plugs" in the Entire Forum, tells all.
Swarfy.
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Mystery to me how this has come about but the 5/8" plug was too small so ordered 7/8" plugs but as these are 11 tpi won't fit the 20 tpi(?) thread in the crank. Having a bit of a time measuring the tpi but it seems the crank has either been modified or built up with different parts. I will search through my Triumph bits from the last motor I did and see if the Triumph plug will fit. Certainly hope I find the right plug as this is the only thing holding me back.
Frank
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Gentlemen,
Working away at the A7 engine rebuild and waiting for what I expect will now be the correct sludge trap plugs and meanwhile turned up what might be a spare crank in the boxes for bits that came with this motorcycle. I have a few pics here to show what puzzles me about what I have for cranks. Second two pics are the crank that came out of the engine last two are the crank from the bits I got and first photo is the two together. First crank has shorter splines for cush drive bearing and 7/8" sludge trap plug, suspecting this might be the wrong crank I have been assuming was correct and second crank has longer splines for the cush drive bearing, 5/8" sludge trap plugs (one is driven too far) along with a stamping on the crank R010 (needs a good clean before I can get proper readings but might have been reground??). Any bits of wisdom will be greatly appreciated and will continue to look using the search tool but nothing definitive yet.
Frank
ps At least I have the R.E. insured and ready for a ride while waiting.
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Frank. The crank for the Longstroke engine is wearing the ball race on the drive side. Other characters to note.....
Extra widening of the flywheel adjacent to the webs, looks like bit extra added each side extending round almost half of the rim. The mystery crank certainly has this feature, but is lacking the usual Flat Bottomed Cut Out on the flywheel periphery between the big end journals.
These features together are only found on the Longstroke crank.
Drive side shaft measures 98mm web cheek to end of cush nut thread. Splines extend to the thread, there is no plain area as on the mystery shaft.
Drive side bearing size and type differs from later model A7/A10
Other bushes and bearings are the same as later small journal cranks, fitted with split cap alloy rods. Longstroke steel rods with split caps use the same big end bearing shells as the small journal later engines.
Swarfy.
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Thanks Swarfcut,
Finally found a picture of the long stroke crankshaft on Mike's site and it looks like the spare one I have. Now to clean it up measure everything and confirm if I have the correct shells for the connecting rods. The one that was in the engine "as assembled" looks awfully close and the rods fit well but I suspect is from an alternator(?) version of the A7 engine with the clear area on the shaft but will keep on looking until I figure it all out. At least I have the correct sludge trap plugs now so I can clean that up and will get ahead with this one as weather is allowing some riding, above 15C today, so I can get this one out on the road soon.
Frank
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Well, sludge trap plugs came out pretty good and someone has been there already. Real plus the bearing surfaces were clean and well greased R010 stamped on the flywheel must be 10 thou under as measurement with decent calipers is 1.448 vs 1.46, need to get out my decent measuring tools to be certain, so where do I go for 0.010 under shells?? Draganfly only list to 5 thou for 67-0226 but I will search some more as it appears 67-0320 at -0.010 might be suitable.
Existing crank that was in there reads 1.419 and con rods have correct shells for that dimension so have to dig through the boxes some more to see what else is hid in there.
Frank
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Cleaning the supposedly correct crank and found one of the bearings has no second oil passage. If this is what came out of this engine then no wonder it threw a rod !!! Off to my good friends at Speed Valley shop for a little remedial machining will be next.
Frank
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Seeing as BSA were concerned the timing side didn't rob all the oil from the drive side (hence the drilled rod) maybe that was intentional?
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I have quite a few other BSA cranks, amongst others, and never seen anything like this before. Everything I learned in my electro-mechanical career says there must be an even supply of oil to maintain the oil dam and film effect for good bearing performance.
Could’ve someone’s thoughts on balancing flow on this but we will see.
Frank
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How were the little ends? One of mine is a bit stiff so I will need to find someone with a reamer. There are scuff marks on the piston but I think they will polish out. I previously had a short stroke A7 and the thing that stuck me with the long stroke is the much smaller cam followers. They seem to work OK though as the cam and followers are in good condition. I had to renew the followers on the short stroke as they were well worn on the contact faces with the cam.
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Hi,
A Monday morning or Friday evening job??
If it was intentional to not have the hole there they would not have ground the relief in the journal...
A few years ago I saw sorting out a C15T and found the breather hole in the cam bush/ timing case had never been drilled
No wonder I ***** oil out every joint on the engine
John
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Small ends are fine and thus should go together without any more drama, I hope.
Yeah, football was on the telly and Clive wanted to get home on time! Fixed now and just have to drop in and pick it up.
Frank
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Another few days of work and I now have the crankcase tightened up but as I got the bolts done up it is now very hard to rotate the crank. Oh well, guess I take it apart pull the bearing and take the .010” spacer out then reassemble again.
First time doing this particular style of engine but not unexpected.
Meanwhile good weather and the Norton have kept a smile on my face.
Frank
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Fit the drive sleeve and retaining nut. Tighten down hard with a peg spanner. This will settle the ball race against the crank. May save dismantling if the race moves towards the crank.
Swarfy.
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Good advice, did not give me much, so crank moved but with the help of a strap wrench. Not the worst job and I have the tools so half an hour I have it apart then it is just chilling and heating to get everything back in place.
The bushing thrust face is only showing a rub mark in one small area so might just pop that out and check if it is machined correctly as this is one of the plain bronze types and is a little thicker at 0.135” compared with 0.125” for the steel sleeve ones I have as well. That would make a world of difference taking that down as an alternative to taking the bearing off again.
Frank
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To add a little more to comments about the crank oil holes.
Found a Longstroke Crank, split rod type, nicely greased up and with no major scoring or damage to the journals.
Big end journals measure 1.45". Looks to be 10 Thou down, so should shine up OK.
Timing side big end journal has the two ground out slots for the oil hole, but as pictured above, only one hole drilled. So, to drill or not?
Swarfy.
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Hello Swarfcut, after a good while recovering from illness and surgery I am back up and at it again. Have the transmission and crankcase installed and working on the clutch and timing side in progress. Having a problem with clutch adjustment as I have it all assembled, operating the clutch lifts the plates fine but there is a terrible groan from the gearbox as I operate the lever. New plates and well lubricated cable, pushrod and plunger. Guess I will keep looking as this is taking a lot of effort to operate the lever.
I have drilled out the hole on my crank as I could not find anything more on this anywhere, curious that you have one with a single hole drilled but I am going to try this one out and keep a close eye on oil pressure and performance once I have it running.
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Clutch action should not be a gorilla fist requirement. Rigid/Plunger clutch is a sound design, but a few things to check.
The split collar 67 3251 on the mainshaft supports the thrust washer, which to my mind hangs on by its fingernails, the collar groove in the shaft is minimal, even on new shafts. Failure of the split collar or its absence lets the thrust washer run against the oilseal rivets.
Aftermarket clutch rollers can be oversize lengthwise, this will lock up the basket and centre when the mainshaft clutch nut is tightened.
First plain plate into the basket is a thick one to support the spring load against the other plates.
All plates should slide easily in their respective positions, and not all aftermarket plates are made equal. Here a wider manufacturing tolerance is perhaps better. With a stiff action and a groan I'd expect witness marks here and there where components are binding.
Noise from the rotating gearbox with the clutch lever pulled is is likely to be a bad ballrace in the inner gearbox cover, as this is loaded axially as the pushrod is trying to push the clutch and mainshaft towards the driveside.
The main failing with the design is that the basket is poorly supported laterally and even with new components a degree of shake on the chainwheel is expected. They all do that, Sir....
Longstroke assembly of timing covers, magneto, dynamo and front engine plates are a bit of a jigsaw. Assembling the gearbox/engine as a bare unit into the frame is easier, otherwise it's a step forward and three steps back. Trust me.
Swarfy.
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Hello Swarfcut,
All good info, the gearbox and crankcase are in the frame and up on the lift, which does make things easier.
Yes, I pulled all the plates and remeasured the ears on the plates which showed quite a bit of variation in machining so I passed a file over some that had witness marks of dragging. With that done and the cable lubed a third time it is now working quite reasonably but I think I will order a new cable as that is where the noise is coming from. With the cable off and activating the clutch with the gearbox lever it is easy and silent.
The puzzle of the timing side is made worse by the plethora of lock washers that are used but I have the inner done now.
It will get easier I am sure.
Frank
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Well, I placed the rear mudguard along with all the bolts and spacers quite a while back but now it was time to fit the chain, chain guard and ensure alignment. Rear mudguard is too far to the primary side so does not allow the chain guard to fit properly by half an inch so I will have to unbolt, select new spacers re-align mudguard supports and hope it all comes into line somehow. Hah, such fun and it all looked so good before trying to get the chain guard in there
Frank
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Just a quick question on pistons for my A7 LS. Putting in new rings and readying barrel to install but now I notice right hand piston is Hepolite 10030 standard, good but it will not fit in the LH barrel which has a BSA piston 67-196 which is a little loose in the RH but fine in the LH. Question is I do not find anywhere a reference to the 67-196 (yes tried 67-0196) anywhere ! Does someone here have an indication of what this is ? I have a mutitude of parts manuals and BSA piston reference charts going way back but nothing on this particular number. It is going together pretty good although the new Wellworthy oil rings have a gap of 24 thou on them straight out of the box so a bit big but I will figure that out with the supplier.
Frank
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See the 1950 parts book page 238 (available on this forum)
The number is for bare piston 6.6:1 comp.
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Thanks, great addition to my information. It's going back together today then timing and head on. Be done in time for riding this summer, can't wait.
Frank
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Timing done, covers in place. Barrel on then head, looking really good but putting on the valve covers and exhaust installs fine but intake won’t sit properly. Figured out the right side intake pushrod is sitting about 3-4 mm higher? What the hell have I missed something, did I mix up the followers and they are not absolutely identical? Did a quick comparison on the pushrods before sliding in and they looked the same to me.
Guess I will tear everything apart to investigate.
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at least one has to sit higher , me thinks, opening a valve *beer*
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Or the pushrod is jammed beside the cup rather than in it..?
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Have rotated the engine a few times but every time it comes down it still sits higher than the left hand pushrod at rest. Pushrods and armed move well following the cam rotation properly I believe but I will check a bit mor before I lift the head
Frank
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My researches give a pushrod length of 180mm for inlet, 205mm for exhaust (again, do your own checks) In his book BSA Twin Restoration, Roy Bacon says valve caps were fitted to the longstoke engine, but does not state whether they were fitted only to inlet, exhaust or all four valves. However an exploded line drawing on Page 38 of his Twins Restoration shows caps on all valves. Help from the parts catalogue in the Literature Section lists caps 65 209 fitted to all valves on the A7, but none to the Star Twin....The actual valves listed for the two models are different.
Drawing also shows pushrods fit cup down, plain end up to the rockers. The valve gear itself is broadly the same as later engines which do not have caps. Worth checking the rocker arms are the correct parts, match as pairs and one has not been strained.
Camshaft and followers with ball end tops reappear on the later unit engines, Page 95.
Longstroke Rocker Part Nos... Left Side Right Side
Inlet 67 45 67 46
Exhaust 67 47 67 48
Methinks a pushrod from any old school OHV car engine could be adapted in the absence of the genuine article. Your local engine reconditioner may have a few in the junk pile.
All the followers are the same. Overall length 76mm. Unworn tappet block is 12mm deep, Shank of follower from top of the block to top of ball end is 64mm. Caliper and eye, measured on parts to hand.
Swarfy.
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Thanks for that info Swarfy. I found that a rocker arm was not rotating all the way and appearing like the pushrod was sitting proud. Loosened the rocker shaft placed the Thackeray washer correctly and valve cover sits good now.
Frank
Carb, exhaust and tank. Might give this a kick this weekend.
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Good luck! 🤞
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Hah, it is always the little things. I took it off but the PRV is nowhere to be found in my workshop, it must have rolled off the bench and found a really good hiding spot. Oh, and of course I have no carburetor mounting studs on hand so have to order those from Britain.
But soon though, very soon, I will start this bike and go for a ride.
Frank
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Can I suggest not using studs for the carb. I find fitting the carb with gaskets, heat insulator, drip-tray and air filter connector much easier using screws. Take care though that the screws are not long enough to protrude into the inlet manifold.
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Two full days cleaning my workshop, vacuum even came out, there it was sitting between tool boxes on a shelf below the worktop.
Used a couple of Whitworth cheesehead screws with appropriate size lock washers to hold the carb on but had to loosen off the air filter/battery tray to get it all in place as there is no way to squeeze the carb in place.
Took off the sump plate as it was leaking oil and that was with a new gasket and hylomar as a precaution. Will have to consider thicker paper or two layers for the next try.
Exhaust pipes and mufflers went on a treat and it is looking good.
Frank
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Getting close to the starting stage but of course it is the little things. Made up new gas lines, filter in place, original taps from my cache of parts but the banjo bolt seals/washers for the float bowl leak horribly. Back into my horde of carb parts and dug up a few new ones which will go on today and then the kicking begins. Of course there has been a lot of kicking already to prime the oil system and that found a fractured oil line to the valve gear which brings up a question about where can I purchase the banjo fittings so I can make a new line? It will all come together soon I am certain.
My only concern is getting up on the centre stand ! What a horrendous effort this is. I use a ramp to get the rear end up 3” then it is alright but I will have to pack a wedge shaped piece of block around all the time. I will have to modify the bolt-on side stand so it works properly then re-install and that will be handy.
Breakfast is done and now for some exercise!
Frank
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The centre stand is yet another of BSA's design errors. How could they make so many on such a beautiful bike?
Anyway, a while ago (under a year if I recall) I posted some words and pics about shortening the centre stand so the rear wheel is only just clear of the ground when on the stand. By adding a lug to the side, heaving the bike onto its stand is no longer required - just put a foot on the lug and the bike rises onto the stand with no help from arms required.
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Now that is some information I could use. I had a quick search but did not find anything right away so might have to look harder. My thought is to fix the side stand then I will take the centre stand to my son-in-law’s shop and have it chopped a bit then re-welded and a foot lug is a good idea for levering it up.
Any notes on how much you shortened the stand length?
Frank
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... where can I purchase the banjo fittings so I can make a new line?
I enjoy plumbing; I would be inclined to remove the damaged pipe and solder new pipe into the old fittings.
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fff- came up straightaway (usually I struggle with this forum's search facility) - presumably this will take you there? https://www.a7a10.net/forum/index.php?topic=15800.msg134906#msg134906.
If not, pasting 'centre stand' in search should.
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You are right Neil, easy enough to replace the pipe. Was just wondering if there is a source as I need to make a few others and would just cost less.
RDfella, I did not recognize the topic correctly when I was searching. The centre stand on the long stroke bike has feet shaped different than the later bikes but I will figure something out. I have to as it holds the back wheel much too high at 3”. The concept has been proven and it looks easy enough.
Frank
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You are right Neil, easy enough to replace the pipe. Was just wondering if there is a source as I need to make a few others and would just cost less.
Small copper pipe should be available but hydraulic brake pipe might be an alternative and would bend safely.
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Getting the bike off the stand can be just as difficult. Plunger stands have a poor stop arrangement for the "Stand Down" position. The stand itself has two small ears which bear on the two flats formed on the underside of the footrest mount frame forging. These parts wear over time, and the stand will then allow the bike to sit lower when on the stand, hence the hernia inducing effort to lift it up and off the stand. The ears can be built up with weld, as can the frame forging. Easy to do as a first restoration step, not so as a final overlooked detail.
Good unworn Plunger Stands have a fair value these days. I would be reluctant to put one to the axe. A low ride height will make using the stand harder to user, more physical lift required, so I'd only modify the stand as a last resort.
Swarfy
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So proud of having the original correct taps but despite new corks, boiling water, correct washers, etc ; they did not stop leaking. Okay, put another set of taps on and now that works better. Leaks at the base of the carburetor to float chamber, replace seal washers twice then realize the float chamber collar where the banjo fits is not correct. Careful dressing of the collar top and bottom has the leak at the banjo bolt all sealed.
Now we are getting somewhere! Tickle the carb, kick, kick, many kicks, pull the plug and no spark. What? The mag produced lovely fat sparks when I spun it with a drill on the bench before installation. Clean the points, recheck the cables and try again but no joy. Thank God for the rain, I have an excuse to walk away and think about this some more.
Slip ring dirty? Brushes knackered? Need to check the ground again? It will be something I have done I am sure.
I love my motorcycles! Strange but true.
Frank
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Hi Frank,
If you blocked the hole at the base of the body where the fuel leaks out you will have trouble!! Ok so fuel leaks out but when the engine starts it acts as an air inlet
Look for a sectioned drawing of the pre mono 276 on the net
John
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Oh, I have you on that one. The leak was where the banjo tightens on the collar that attaches the float body to the carb body (must look that up as there must be a proper name for it). The Mazak was dented and misshapen so cleaned that up and did not touch the breather holes (atmospheric vent holes?). But thanks for the reminder.
Today it will be a bit more valiant effort then the BBQ with the wife and girls. Good fun
Frank
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A quick update, cleaned the ground brush and slip ring, new pick-ups with brushes and wires. A few kicks but no joy…. Ah yes, reverse the leads, tickle generously and second kick it roars to life, only ran 4-5 seconds then died. Tried a few more times with same result so I guess I will tear into the carb to do a few more checks.
I was doing a jig the as sign of life made me so happy. Oh yeah, found another small oil leak that will take a little fiddling.
Frank
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Back at the bike yesterday, damn life gets in the way sometimes, oil line tightened, new washers on the banjo bolt then replace one of the tank taps. No joy, so checked for spark with left good and right nothing. Checked leads with a meter again, the plug cap on right is now showing open; new plug caps both sides, fill up the tank, tickle and the bike started on second kick!!! Ran pretty good, sounded right so after a minute or so turned down the idle adjusted the pilot and it was terrific for another minute or so then just stopped. Many kicks, pull the plugs and they are dry so I will clean the carb again, blocked jet maybe, and oh yes the oil line to the top end has another fracture so I will rebuild that completely.
Such fun, but it was encouraging.
Frank
ps I have been getting some riding in as the weather has been fair and my last rebuild, ‘71 Norton 750, is a pleasure.
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And, it starts and runs fine at last! So glad it has come to life and sounds quite good. A few minor oil weeps causing a little smoke but now to get it out and get some miles in.
Frank
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Now I am tearing my hair out fiddling with the carb. Starts well and did run quite well but now it is running much too rich just won’t accelerate worth a damn. The float just never quite stops the flow of gas and the excess is dripping from the atmospheric vent. Tried another float and needle but that does not help it seems and now to try a 1A body instead of the 1AT body the PO had on there and maybe a washer to modify the float level lower.
We will see in a day or so what is happening on this.
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Frank you need to lower the float bowl in relation to the jet block. Experiment with fibre washers added between the base of the carb body and float bowl mounting banjo. You can check the float valve works in isolation. Fuel level is just below the top of the needle jet housing in the carb body. Any higher and fuel will continue to overflow, dripping from any available orifice. Service Sheet 708 shows a cutaway and will help you get a handle on what's going on.
276 Carb can be fitted with various remote float chambers, on later models the carb sits at a slight angle and requires a chamber which sits level at rest. It's all to do with the bowl casting used, they come with the mounting set to slightly different angles. So always a chance the bowl you have is not quite correct for your early type cylinder head and manifold if someone has fitted a carb from a later model.
Swarfy.
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Yes, I have to drop the bowl along with the correct model and I trust this will make it work.
Frank
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Right, proper 1A float chamber, extra washer to drop it down, lo and behold the float works properly. One job done so on to starting which was third kick but running on right hand cylinder only. There is good spark, plug is wet with gas, compression seems good….. what is happening here? Cleaned the slip ring on the mag, tried another plug but no firing on the left hand.
Will check the points gap, install another set of plugs then I will consider this in depth.
Frank
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... running on right hand cylinder only.
Some people want perfection. You'll be wanting the moon on a stick next. 😉
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Could be a poor pick up/lead. Swap plugs over, together with the leads. Leave pick ups for now. If fault changes sides, mechanically it's fine, the problem is the lead/plug. Stays the same? Plug and lead good. Suspect pick up. Sparks in the open air are a guide, HT does strange things under compression.
Swarfy.
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Sparks in the open air are a guide, HT does strange things under compression.
I remember using a testing and cleaning machine for plugs. There was a sand blaster section and a test section. The plug could be seen through a little window. When the plug was energised you could see a nice blue spark. Compressed air was blown onto the plug and the pressure was increased. If the plug was no good, the increasing air pressure would stop the plug from sparking. I found this picture.
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Thanks guys, I have new pick-ups, leads, caps and plugs installed and it ran quite well for two sessions of 10-15 minutes while setting the carb. Tried going down the road but it just would not go and carb leaked gas continuously so changed the float chamber, lowered the fuel level with an extra washer so things are good but now it does not fire on the left cylinder.
I have used the plug testers a lot, army workshops did not have them but every garage I worked at after that had them.
I should have another set of plugs delivered today, I will swap leads over and I am going to check compression properly again (finger in the hole is not a proper tool) as I have had head gaskets blow at start before.
There is something I have missed here and I will find it. I am hoping this one puts a smile on my face as I have another ‘48 waiting for rebuild and I want to feel it will be worth it.
Meantime it is worth airing these problems among like-minded riders.
Frank
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Hell, I said a finger down the hole was not a good tool. 75/ 116 lbs compression left/right so off with the head and see what has gone wrong. I suspect a sticking valve, broken rings? I will see what is up in a day or two, have to take my wife for surgery this morning (not too serious) and that is more important for now.
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Easy stuff first. Tappet clearance...if it's not what you expect it's the valve/guide or a mis -placed pushrod. Or simply a poor locknut. Rocker boxes off to check freedom of movement of the rockers on the shafts. Leakage test on valves- as a quick test put an airline on the plug hole and listen, cylinder set to TDC, valves closed. Custom adaptor useful here*. Ring problem unlikely, but worst case jug has to come off.
Swarfy
* Made one years ago from old plug, steel tube, airline connector. Used to hold valves closed to change valve stem oilseals on OHC vehicles without major dismantling. Beats the old rope trick.
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Yes, take it in stages and I have an air line adapter for my compression tester with quick disconnect. Done a few jobs like that myself. Just a process of elimination and tracking down the fault.
Just to add insult to injury the back tire went flat on the last ride up and down the block, just have to laugh!
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Health was an issue for a few months but doing better again so back at a few bikes over the holidays. RE Bullet is coming along fine thanks, Thunderbolt rebuild started and parts arrived for the Ariel’s but the best was installing the repaired rear tire and cleaning up plugs and points then starting up the A7. Okay six kicks, but once it fired up it ran terrific and sounded so good. Now if there was not two feet of snow and -6C I would have tried a ride out. May have to wait a month or two for a test ride but we will see.
Happy New Year to all !
Frank
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Well, health issues again but it seems they have put me upright again so better get back in the workshop again.
Maybe I am a little bit wrong in the head but I have in mind to take on the rebuild of my second ‘48 A7 LS. Very little missing from this example so should be a quick job, right? I need something to keep me occupied this winter also I will try and keep up to date posting.
Frank
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April of 2024 now and cancer bother and surgery done. Back on the mend with good drug therapy’s under way which should allow me to get back in my shop by mid May then I will update where I am going with my second ‘48 long stroke I hope. A good friend of mine is quite interested but he has a ‘69 Norton ‘S’ I just gave him to finish up first.
Frank