classic motorcycle forum
Motorcycle Discussions => British Bikes => Topic started by: ramwing7 on April 08, 2026, 09:58:05 PM
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I have a 1949 BSA B31. The gearbox is a mess so I got another hoping to use two to make one serviceable.
I've come up with a situation that I cannot find any information on.
In one gearbox the mainshaft gear (24-4231) slides on the shaft easily. In the other it took 5 tons of pressure to remove the gear from the shaft and if it goes back on, it will take a press to get it there. The easily moveable one will not slide on the other shaft either.
Question is: Which it correct?
Does the mainshaft gear move along the mainshaft in normal operation or is it supposed to be fixed and stationary during operation?
Many Thanks.