Well I finally got my bike together and have two engines. One is completely rebuilt but the lower case is leaking from where my friend put it back together. But...... the one that is in is the one I bought off of ebay and I took it out for a high speed run today and it turns out that this one the gear is slipping. It will be going find then all the sudden slip then catch and keep pulling. The sprockets and chains are all brand new so that aint it. And when the other engine was broken down I had to order a 3-4th gear because the one in that engine was dog earred and worn.

So my question is does this happen often? Is this a common problem because I have two different engines and both have bad third gears....

cajun wrote:Well I finally got my bike together and have two engines. One is completely rebuilt but the lower case is leaking from where my friend put it back together. But...... the one that is in is the one I bought off of ebay and I took it out for a high speed run today and it turns out that this one the gear is slipping. It will be going find then all the sudden slip then catch and keep pulling. The sprockets and chains are all brand new so that aint it. And when the other engine was broken down I had to order a 3-4th gear because the one in that engine was dog earred and worn.

So my question is does this happen often? Is this a common problem because I have two different engines and both have bad third gears....

I have bad second gear on my last engine. The new one was RLRMotors engine - all gear is fine, but not easy to find neutral. Sorry, not too much help... but in generall not too much claim on gearbox from NC29 owners.

They are known to have a weaker gearbox than the nc23.. not sure just how weak that is.

Dodgy 3rd/4th gear is pretty common.

One thing to check when you have the gearbox apart is that the selector forks are straight. They can bend in a crash etc (I know from painful experience) and not push the gear far enough to engage, resulting in knackered engagement dogs on the gear. If your ebay engine had a crash it could be the cause.

Crap...... And the gear isn't made anymore either....

I think the gears themselves are the same as rvf400, Greggo might be able to confirm.

Cammo wrote:I think the gears themselves are the same as rvf400, Greggo might be able to confirm.

I think no.
1,2,3rd gear a different.
All other is the same.

But Greggo might be able to confirm

PARUS wrote: I think no.
1,2,3rd gear a different.
All other is the same.

But Greggo might be able to confirm

Parus, pretty sure all gears are the same. It's the 1-3 gears of the VFR400 that are different to NC29 and RVF400 (VFR400 is closer ratio).

Greggo modified his NC29 gearbox to take the first 3 close ratio VFR400 gears (an impressive bit of work!!), I supplied the gearbox.