Gearbox woes? Any suggestions welcome..

A

avsjack

Well-known member
Hello all,

So I got my 1981 Yamaha Exciter 185cc running today (See project tutorials), and I managed to take it for a brief run up the street. Everything seems to be going OK except I had a little trouble with the gears.

It goes into first gear really well, I pull in the clutch and shift up, but in order for it to stay in gear I have to hold up the gear lever while I release the clutch, it is then engaged. This seems to happen right through all gears pretty much and also when changing down. If I do not do this, it seems to find neutral between each gear change. (Well it's kinda neutral 'no drive' but the neutral light does not come on, on the dash).

I reckon I have encountered this before, I also reckon the gearbox may be a little noisy. Does anybody have any suggestions? Is there anything that is adjustable perhaps?

Any suggestions will be very welcome and very much appreciated!

Gearbox.jpg
 
Disclaimer. I am not familiar with the details of that particular engine. What follows is generic how-it-works type stuff.

Somewhere inside that engine is a mechanism that rotates the shift drum when you operate the shift lever, and there is a mechanism with a spring-loaded lever/idler-roller and a detent wheel that holds the shift drum in position in each gear (or in neutral). I betcha either that spring is broken or some such thing, or corrosion is causing either that detent roller or the shift drum itself to not move freely when you change gears.

Generally, this shift mechanism will be accessible underneath a removable cover of some sort, often near where the shift rod goes through the cases, although sometimes it's behind the clutch basket. This is where you need to get the shop manual for the bike and find out how to get to that shift detent mechanism.
 
Hi Brian,

Yes, this is exactly what I was thinking. Almost certainly a detent type thing, unfortunately being such an old bike, there is no panels for easy access, just the two engine casings. But when I did something similar like this on an old Royal Enfield it was just behind the clutch basket I reckon. Fantastic advice on the book, I will look online this weekend. Nice work with the disclaimer, no legal action will be taken! ha

Thanks Brian, very much appreciated.
 
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