BSA Owners' Club Forum

The BSA Workshop => Twins => Topic started by: Captain Mike on 04 June, 2021, 13:54:03

Title: Baffled with gearbox clutch
Post by: Captain Mike on 04 June, 2021, 13:54:03
Hi I recently installed new friction clutch plates on my six spring BSA Plunger clutch, once set up I left the primary drive casing off so I could make more adjustments if needed, started the bike put the gearbox into 1st, set off changed up and down as smooth as it gets without a problem, put the casing back on again and came to start the bike again the next day and could not select any gears, loud crunching but no selection, What the Hell ! is going on !

I can put the the bike in gear and then push it with the clutch pulled in and it disengages the drive, but when I start it I cannot select any gears

New clutch set up correctly working fine the day before ???

Any ideas as to what is going on ?

Title: Re: Baffled with gearbox clutch
Post by: Jim S on 05 June, 2021, 12:56:21
Hi Mike
Maybe the studs on the clutch basket are contacting the inside of the cover?

Title: Re: Baffled with gearbox clutch
Post by: DAVE BRADY on 05 June, 2021, 16:15:44

When you say casing do you mean the 'pan' cover that attaches to the clutch or the primary case?  If it is the 'pan' then if the adjuster screw is too far out it could foul the inside of 'pan' when the pressure plate is lifted.  If you do not have the 'pan' fitted then it is very unlikely that adjuster would contact the inside of the primary case.  It may be worth taking the covers off to see if there are any telltale marks.  To be honest the 'pan' is surplus to requirements. 

Title: Re: Baffled with gearbox clutch
Post by: Captain Mike on 07 June, 2021, 06:26:36
Thanks for the comments and Ideas

I will be investigating this week so will come back with the results

Title: Re: Baffled with gearbox clutch Resolved !
Post by: Captain Mike on 09 June, 2021, 14:01:53
Hi all

As per my last post and gear selection issues , I pulled the outer case and found one of the gear selector returns springs had escaped jamming the selector

The spring escaping has happened before and these were new springs, seems to me that there must be some wear in the channels that hold the springs under the selector that is causing this, anybody had this happen to them ?

I will be looking to build up any areas that I feel are worn with chemical metal then see how I go

Title: Gear change return spring escaping
Post by: Captain Mike on 20 June, 2021, 10:24:11
My gear change return spring has escaped from my gearbox outer cover, this has happened twice, I replaced the springs for new and it happened again, there was some wear on the selector spindle that holds the springs in place so I found a replacement and fitted that also, however I am not sure if there is some wear on the on the gearbox outer casing in the channels where the two springs sit, I am ready to put the gearbox outer cover back on again with the new springs and selector arm spindle however I am not sure this wont happen again, my question is; does anybody have a picture of an A10 plunger gearbox outer cover that shows clearly the two channels where the return springs sit for reference to to see if mine is worn or does anybody have any ideas why this would happen