Author Topic: 1953 b31 plunger gearbox  (Read 203 times)

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andy1953

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1953 b31 plunger gearbox
« on: 27 August, 2017, 07:21:40 »
hi hope some one will be able to help i am in the process of putting my dad,s bsa back on the road and i am having trouble with the gearbox 3rd gear will not engage properly it seem to need 2 stabs at getting it in gear all the others work fine i have had the box apart and looking at the manual it looks like its all there  is there anything else i need to look at
regards
   andy1953 ;)

chrisgoodwin

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Re: 1953 b31 plunger gearbox
« Reply #1 on: 29 August, 2017, 11:48:09 »
Assuming all the internals are correct and in good shape you could try the gear change control rod which has an adjusting yoke, I set mine up by trial and error.

Greybeard

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Re: 1953 b31 plunger gearbox
« Reply #2 on: 29 August, 2017, 11:48:34 »
Hello, Andy.
As you might've guessed by the number of responses, diagnosing a problem like this isn't always straightforward without a hands-on looksee. I have a 53 plunger B31 myself, but thus far the 'box has maintained BSAs reputation for rugged reliability. This morning I came across a useful article on rebuilding the A and B series gearboxes in a March 1990 issue of British Bike Magazine. It has quite a few good pointers on things to look for. If you think it may help I'd be happy to scan it and email you a copy. Let me have your email via a PM and I'll get on the job.
Steve

I see that Chris has also posted a reply whilst I was typing this one  ;)
« Last Edit: 29 August, 2017, 11:50:45 by Greybeard »
Steve from East Yorkshire - Not the Greybeard of the A7/A10 forum who was not actually registered on this one when I signed up ;-)

Greybeard

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Re: 1953 b31 plunger gearbox
« Reply #3 on: 30 August, 2017, 17:06:55 »
Folks,
I've sent out a couple of copies of this article - only 4 pages. If anyone else wants a copy as it covers the gearbox used on both the A and B series bikes, please ask. Just let me have your email address by PM.

Steve
Steve from East Yorkshire - Not the Greybeard of the A7/A10 forum who was not actually registered on this one when I signed up ;-)

GBonduel

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Re: 1953 b31 plunger gearbox
« Reply #4 on: 30 August, 2017, 22:53:44 »
PM sent, I also have a B31 Plunger but haven't had any problems with the gearbox yet.