Hi folks, can anyone suggest what would be an appropriate amount of side to side play (endfloat I guess) for the selector shaft in an S29 3 speed gearbox ?
I've just done a brief test ride after reassembling the box with a replacement selector shaft (the original fractured at one of the fork collars) and find its a bit uncertain when shifting into 2nd gear. 1st and 3rd seem OK.
When 2nd is engaged with the engine stopped, bike on the stand and the inspection cover removed, I can lever the selector shaft towards the ks end so that I can get a 30 thou feeler gauge between the shoulder on the shaft and the bushing at the clutch end.
Seems like quite a lot of play, so was wondering if that could be the cause of the dodgy 2nd gear engagement.
Cheers, Bevan
Hi Bevan. I have had a 1929 BSA Sloper for over 40 years. There should be very little play /movement of the selector fork shaft. If you have say more than a few thou then the face of one or both of the bushes are probably worn. Shimming from one side or the other will cause gear changing problems. The only shim/washer in the gearbox is the hardened steel one on the mainshaft on the shoulder of the mainshaft where it goes into the final drive gear inside the gearbox. Try adjusting the length of the hand gear change linkage. An 1/8 of an inch longer or shorter can make a difference to ease of gear changing. Hope this helps.
Thanks Alan,
Things have gone backwards since my posting unfortunately. I took up a bit of play in the control arm and went to go for another test ride, but as soon as I put it jnto gear, it locked the gearbox and stalled the engine. I have a suspicion I know what's happened, but am away for a few days, so probably won't get back to it until next week. I'll make a video of things since it saves a lot of typing and put a link in this thread if you (or anyone else) would be good enough to take a look and provide an opinion.
Cheers, Bevan