Gearbox Parts Availability

[OlyMoto]

Apologies for the ignorance, I'm still in the "getting to know you" stage with Morinis. Further, this question is necessarily vague.

I've been on the hunt for a 3 1/2 in the US for quite some time. I might have an opportunity to fetch one as-is, with the caveat that the transmission is "not quite right". That's all the info I have on it. The bike is in otherwise good shape.

I'm not naive enough to ask for solutions at this point, but perhaps there's a short list of common gearbox issues. More importantly to me, is what parts availability is like for anything that might need replacing in the gearbox. Clearly, I'd not expect to find much here in the States - but are gearbox components still available across the pond, or are certain parts now unobtanium?

Thanks.

[morini_tom]

New gearbox parts are hard (impossible) to come by but generally speaking they don’t go bang in a major way so used clusters and components should be ok to source.

Can you find out more about ‘not quite right’ means and we might be able to give more specific advice.

Very early gearboxes had aluminum selector forks which wear and give selection issues. The factory changed to bronze forks quite quickly and the bronze ones are interchangeable with the aluminium if you found that to be the cause. Although I’d be surprised if many bikes were still running the aluminium forks.

Selection issues can also be caused by broken or dislodged return spring. Although a trivial component to replace in itself, this does need to split the crankcases to get to.

If the engine has been recently rebuilt then selection issues can also be caused by incorrect setting of the selector pawl stop plate. The blue book describes the process to do this using a cutaway crankcase (which most people won’t have). Again, it does need an engine strip to check/reset.

On the other hand, selection issues can also be caused by badly adjusted gearchange mechanisms especially if rearsets have been fitted or a left foot gearchange. Slop in the linkages, worn rose joints, bendy rods, or parts touching the frame or engine cases will cause issues. All these things can be fixed easily with some careful observation of what’s going on and fettling where required.

[OlyMoto]

Appreciate the detailed reply, Tom - thanks!

I'll try and get more info on the symptoms, but I'm not being led to believe a "bang" occurred. It sounds less dramatic than that.

[simonnorthroad]

Have lots of gearbox spares if you need them, though I am in the UK

[OlyMoto]

Have lots of gearbox spares if you need them, though I am in the UK

Thanks! Good to know, I'll be in touch if needed.

I'm being told the bike pops out of third gear under reasonably hard acceleration. If riding is less spirited, it's usually fine.