My 52 BSA B33 is from time to time popping into neutral when shifting. It never slips out of gear into neutral when under load but it seems to happen only when upshifting. On my list for things to work on in the fall is sending the mag out for a rebuild and taking a look at my gearbox to see if I can find the source of the problem and have a good look at the insides of my gearbox. The bike is new to me in the last 6 months so finding things out as I go.
Photo attached show my gearbox, I have been told by a friend that knows a bit about BSA's (mostly prewar) that I have a Burman gearbox but he is not sure what model the gearbox is. Before I take the gearbox apart I will want to know what year the box is or some kind of identifier for the gear box if I need parts or support literature for guidance on the rebuild. So a couple of questions please.......
1......Can anyone tell from the photo what year or model number my gearbox is?
2..... I use straight old school 50 weight oil in Engine, Primary and Gearbox. Any chance using something different than the 50 weight in the gearbox will help from the box wanting to find neutral.
3......Also when I bump start the bike I normally put it in second gear, pull in the clutch and push to speed and then off we go - but lately the bike will fall out of second into neutral on its own and it never used to do this.
My guess is the cam shaft that moves the selector fork on the lower layshaft is allowing the first and second gears on that layshaft to somehow slip into the neutral position. Any tips much appreciated........wayne
