gearbox help needed.

[weedossmc]

Hey all need advice on a consistant gearbox problem. When in sixth gear it keeps jumping out and then goes straight back in again constantly, it makes one hell of a grinding crunching sound when this happens. I stripped the gearbox about six months ago and could,nt find any thing wrong apart from some slight wearing on the geardogs and slots for the geardogs on both second and sixth gear, but the wearing does,nt seem too bad.
Bought another gearbox in the hope that i can make one good gearbox from two, but any advice/help would very much be appreciated.
So i,m going to strip it again once it passes it,s M.O.T.
I know second gear going kaput is a common fault on nc29,s and this meshes with sixth gear so could this be the problem?
but for some reason i,m not convinced that it is the gearbox, it only seems to do it under hard accelaration.
I,ve bought everything from new clutch, chain and sprocket kit and rear wheel bearing,s and so on just in case it,s somthing else, but i,m at a loss and need help before i start.
P.S the person with the winning ansewer can place a donation to 400 gb on my behalf and generally feel pleased with themselves (LOL).

[tanuki]

just out of interest how easy is it to get to the gearbox on a 29?

[weedossmc]

so long as you stick to a haynes manual and take your time, it was suprisingly easy?. but i,m weird and love doing this kind of thing. some of the things that the haynes manual tells you to take off, you don,t have to.
best peice of advice i can give you is constantly double check everything your doing and take as many photos as possible just in case.
best of luck if you go for it.

[tanuki]

do you know if you have to split the casings?

[weedossmc]

Yeh you need to split the casings, but it was no great hassle. It,s just taking off all the other parts so you can separate them thats a bit time consuming, suppose it means you can give them a check over when you take them off anyway. If you do go for it, just take your time and read and re-read the manual and you can,t go wrong???.
(if i can do it, anybody can do it), granted i made a mistake in not checking all the gearbox components hence why i,m doing it again.

[tanuki]

I am not to bothered had the head off and cams and stuff out last year but I think my gearbox is on the way out (I will find out at cadwell on the 2nd) but I have a good gear box here so I think in the winter I will swap the gearboxes and may as well re ring it while I am at it.

[weedossmc]

Don,t do it when you,ve had a few beers, that,s probably where i went wrong. Still it was fun, just like a giant jigsaw with out the picture??? :D