Hitchcocks Forum

Box seems to jam when changing up and pedal wont move, but eventually responds and changes. Not every time. No problem changing down. Clutch seems to be releasing okay, and I have renewed gear change ratchets, but no success. Is a box strip down next? Any help welcome. Cheers. GWR.

I'd be looking for something binding in the operating mechanism. Possibly operating shaft part FC47E. This sits in a steel bush which is sometimes quite roughly finished and sits high in the gearbox so doesn't get a lot of lubrication. Also it's matching lever FC48F which runs on a spindle and can bind sideways. While you're there, check that the detent plunger H61A, isn't over tight, this only needs to be about 1 to 2 turns in to positively locate the gears, folk often overtighten this thinking it will help select gears better.

REgards, Mark

Thanks Mark, I will investigate your suggestions. Gordon W R

Worse for any particular gear?

Hi TimNZ. Happens mostly in the higher gears, but all havedone it at one time or another, but only changing up. Going down is not a problem. Gordon.

Make 100% certain that the clutch is adjusted and freeing fully, and that the pressure plate is not lifting crocked...


Internally: as Mark said.


Otherwise it is due to undercut in the dogs on the layshaft and the sliding gears.

Hi GWR, It is also possible that the mainshaft sleeve is broken or split, not a common occurrence, but I have replaced two such items in gearboxes from big twins and one in a 5 speed 250. First and second gears usually select fine, while the higher two [or three] become difficult or impossible to select. This is one rare case where an Indian replacement part might be stronger, as they are not bored out on the insides for a bronze bush to fit inside, but have a resulting greater wall thickness and run a steel to steel [not ideal I know] fit on the mainshaft itself. Cheers, Paul.

Thanks for the ideas. There may be something in the clutch suggestion as changing at higher revs is more difficult than at lower. I'm dismantling the box anyway Thanks all, Gordon.

Problem sorted. A bowed clutch plate replaced, so clutch separating more cleanly. However, Hitchcock's indent plunger a lot better design than old one and changes a lot less notchy. Thanks all.