I picked up this A65L last weekend. It is a 1967 model and has sat for 20 years in a neighbor's garage. All I've done is give it a good wash and a visual inspection. The engine turns over on the kickstart, but I have not attempted anything on it yet.
I'm curious about the front fork. The PO said something about Betor forks, but didn't know much (anything) about them. Does anyone know about them?
Also, if the eagle-eyed notice anything about the bike, I'd be grateful for any/all comments. Although I'm familiar with bikes from the 80s on, I know nothing about BSAs of this period.
If you have a lathe , make a double diameter pushing piece ( drilled through centre for 1/2" + clearance) that fits the bore of the bush and the bore of the SA, mine drew in with a 1/2 " screwed rod through the middle and some nuts to squeeze it together. Make sure the bore of the SA is shiny bright, de burred and check ID matches Bush OD. A whizz with some 100 grit wrapped round a stick in a power drill will help clean the SA bore .
The most important thing is layshaft endfloat, this should be ~ 0.003" Assemble just the lay shaft and its gears / spacers into the end plate and bolt up, check the end float with a clock gauge if you can, a crude test is a push / pull , 0.003" is just perceptible, if it clunks its too much, the spacing is set by the thick spacer that buts between the end gear and the drive side. or an accurate reading can me made by putting lead wire around the shaft between the end layshaft gear and the drive side . Bolt up to squish the lead, strip , measure lead thickness, subtract 0.003 , thats how thick the spacer should be.
Take an oil stone across the faces of all gears with dogs , stone off any raised burrs. This stop the gears trying to skip out as they enter the female dog holes. Same goes for female dog holes , stone off any raised burrs.
polish the face of the cam plate where the selector forks run. Polish the track of the cam plate plunger.
Cut two turns off the index plunger spring, if it hasnt been trimmed already. This makes the change a little lighter and more positive.
i think its important to install circlips with the open ends at the cutout, the worst way is to install then so they look like a C, they should look like an omega sign with the gap at the bottom, if installed like a C so the ends are at 90 degrees to the axis of travel then the accel, decel of the piston at each end of the stroke can cause the clip ends to move.
Some thoughts. The grease isnt helping, remove it and use EP 90. Have you replaced anything in the gearbox? If you have look there first. Until the main shaft/ kick rachet nut is tight all bets are off, this must be tight enough to set the correct spacings for the gears to slide/ clear/ mesh. might be a good idea to fit the chain , and rear wheel, with brake, this helps when tightening the sprocket and spinning the box. A 12 " adjustable spanner/ wrench can be used on the flats of the gear change quadrant to help move the cam plate, with the nuts up tight it will not move easily / at all by hand . I regret using the phrase " light" earlier. Make sure all shims are in the correct positions, use diagram B30 in the manual, I have forgotten to fit the spacer on the timing side end of the mainshaft before. This spacer is easily shed from the cluster when its been stripped and its very easy to misplace.
Heres a good thing to try. Assemble the cassette with no index plunger and spring. , does it engage all easily, obviously there is no detent but its easy to feel what going on. If thats OK , assemble with the plunger and spring, initial stiffness will settle in with use. All tests should be done with rotating the gearbox sprocket,to simulate actual working conditions, spinning the input shaft should not be needed.Its nigh on impossible to judge how the box is working with out the chain and wheel spinning it.
Some if your clutch adjusting nuts look sunk beneath the top of the cup? You want to aim for the top of the screw head being in line with the base of the flat, screwing in further will apply more pressure and weight to the lever.
I agree with Allen and the way I usually adjust the springs is to screw them in until the springs are coil bound and then back off the adjusters a couple of turns so that when the handlebar clutch lever pulled in and Kickstarter used, the clutch spins freely. You might need to screw the adjusters in or out accordingly but the idea is to get max spring pressure and minimum drag. It's probably best to err on the side of a bit too much much free play as in the real world these clutches can drag a bit when cold.
That spring is too tight or is the wrong spring. The leg closest to the plate is already starting to take a short cut. It’ll do this if there is too much tension on the spring or if it’s the wrong material (not spring steel) when you use the kick starter that leg behind will jam up.
If you back the plate off half a turn and the kick start lever is sloppy then you have the wrong kind of spring.
You’ve also put teeth marks on the kickstart shaft which might bind on the case when it’s fitted.
Find a steel tube which slides over the shaft, then fit the kickstart lever (obviously the shaft will need to be cut so it’s the correct length and butted up to the lever when fitted.
As someone mentioned earlier, your getting through this very quickly.
Firstly you need to take the head back off, 1) to anneal the head gasket, that thing will never seal unless you heat it to cherry red all the way round, you can then quench it to help remove the carbon deposit.
2) more importantly.... that’s this turd at the top of the cylinder?
It looks like something is breaking away, this needs investigating and sorting because if it gets worse you won’t have a Nice cylinder for very long.
The next one is the Siamese pipe, there aren’t any decent ones on the market unless you stumble across an original one, I have an original and I made a copy from that. However that’s not possible for a lot of people, the main problem with them is this:
The right hand down pipe hasn’t been cleared properly before the mating pipe has been brazed on. What happened with mine was the gas couldn’t escape properly and it buggered the left hand cylinder. The picture was taken after I had started dremelling all the excess metal away so it was worse than that, by the time I had finished there was no lip, but gas flow on these pipes is still poor compared to an original pipe.
Don’t know if you know or not but you’ll also need some 5/16 rod (or 8mm) to make a tie rod that fits through the tubes at the headers. The problem with the left hand pipe and why it won’t go in properly is because there is too much curve on that left hand pipe. There isn’t enough straight section. Seal it in with RTV sealing and tap it in as far as it will go then put the tie rod in.... you’ve also forgot to put an exhaust clamp on where the two pipes meet.