Colchester student top speed problem

Hi, wonder if anyone can shine any light on my problem. I have an old Colchester Student, that is jumping out of gear, mainly when I try and run it at the two top speeds. Any ideas where I should look first, and what should I be looking for. Pictures of the offending parts would help. Hope someone out there can advise me, thanks

HI Tony, first thing I would do is remove the headstock cover and have a look inside as you select through the gears [ not when it's running ] and see what's going on , some pictures as well so others will be able to help.

Mal.

I run an old 6" Student sq top.......

found when I bought it it was coverd in a thick dried oil glue.....

partic in the notches and indents around the gear selctor (threading)

but it could be as simple as a loose nut/bolt on the selector mech.....

R the levers loose and / or moving fully ?????

try the simple things first cos it's usually them.....

I should get mine outta storage v/ soon if u get stuck pm me.....

be happy to help......

Hi, problem solved. Removed top cover and watched what was happening as I went through the gears. I noticed excessive sideways movement when engaging the gears for top speed. The gears are meshed in with dogs on the side of the gear for this speed. These are slightly worn but that wasnt the main reason. The 1/2 inch unc wedge lock nuts that secure the selector spindle were quite loose. In fact only finger tight. I think because they'd obviously been off a few times they'd lost there ability to lock in position. A combination of worn gears and movement on the selector shaft was causing the problem. I've replaced them with nyloc nuts, and so far it's been fine. Thanks for your help and hope this solution is of use to somebody else

Thanks for news of the solution! Glad that you found it and solved easily.

Howard