Had the r1 locost on track for the first time last week and its started to have problems with the 1st / 2nd second gear change. Basically it likes to slip between the 2 under load unless im sooper smooth with gear changes which isn't that easy.

I believe its a common problem caused by the meshing dogs on the gears getting worn to a pyramid from there usual straight profile.

The solution is to grind the dogs to a "dovetail" profile . I have a milling machine and can do this myself but would need to buy a rotary table to do it. So before i go ahead and splurge on a rotary table does anyone offer this service or have experience of doing it?

Engine is a R1 2000-2003 5pw , but should be the same as earlier 4xv engine/box.

Cheers

Paul

From memory the box shared with the 5PW is the 5JJ and not the 4XV

Also isn't there some kind of hardening applied which ones you're rounded the dogs has gone. If you machine them this will still be gone and so they'll wear quickly.

Maybe this can be reapplied?

will only be grinding off 0.1-0.2 mm , which should still be within the hardened coating . + I'll be grinding off the bottom of the dogs so there angled and effectively hold it in gear under load , the bottom won't see much load as the gear will be fully selected by then. The top initial engagement surfaces shouldn't need much if any material off them.

They could be re-hardened , not sure how i could DIY that tho.

Believe the 4xv/5jj and 5pw all very similar. I have a 5pw in the car which replaced a 4xv lump, sump/clutch/cases /mountings all the same so probably all share the same gearbox design. But as i've never had one fully apart there could be a lot of differences i don't know about.

You need to undercut them,not recut them straight.

If you look at all newer bike gearboxes they are undercut as standard.

The hardening does not matter once they are undercut.

I had a gearbox done by a company in the USA,Fast by Gast.

I bought a gearkit off Ebay USA and got it delivered to him to undercut the gears then he sent it to me.

I never used it in the end and sold all the parts I was getting together for a turbo build.