Gear box

feetup · Post by **feetup** » Sat Sep 01, 2012 5:07 pm

I have a 1960 Matchless G12 and it jumps out of gear as soon as I set off any suggestions and advice would be a great help,Thanks.

GOLDSTAR · Post by **GOLDSTAR** » Sat Sep 01, 2012 5:14 pm

I had a similar thing with a Burman box, turned out to be worn dogs on first gear, mind you pretty difficult to see anything wrong but changed gear pinion and all was O.K.thereafter, kind regards

should have asked if it is a recent experience or not, could also be timing incorrect or plunger spring weak, eliminate the easier bits first.Edited by - GOLDSTAR on 01 Sep 2012 4:17:02 PM

dave16mct · Post by **dave16mct** » Sat Sep 01, 2012 5:18 pm

It's usually the detent plunger spring broken, rusted or weak. Or it could be the plunger itself rounded off. Look underneath the box for the long dome headed nut. The oil will drain out when you remove it. Dave.

feetup · Post by **feetup** » Sat Sep 01, 2012 5:30 pm

Thanks for your advice and suggestions,Oh the gearbox is an AMC and I have been riding it on short runs using 2nd,3rd and 4th. I hope I have not caused any damage.Thanks again.

GOLDSTAR · Post by **GOLDSTAR** » Sun Sep 02, 2012 9:38 am

probably given the clutch a hard time, I took my' three speed' Burman box fitted to my hybrid G80cs shortstroke to Normandy on a rally a few years back, all was O.K.until the convey was snaking it's way up a steep but very narrow Normandy back lane and we met an opposing car, all had to stop, I can tell you trying to pull away in 2nd at this particular point when it was virtually impossible to turn let alone do the old cyclist trick of side to side, made a very interesting moment, I fixed it when I got home ! later fitted an amc box, fix yours before you have the same experience, kind regards