Using a Z1000J transmission in earlier crankcase?

[Bevelhead]

I'm told that a Z1000J transmission can be used in an earlier engine, ie Z1000A1, if the bearing on the output shaft is changed.. from OD 68mm to 62mm. Anyone know if this is the case, and if so does anyone know the spec of a suitable bearing?

The only reason for doing this is that the J transmissions seem to be a lot cheaper than those of an A1.

cheers, Lee

[zed1015]

Been there, done that and it's not that simple..
You need the output bearing, a spacer and seal which is available as kit from APE.
The bearing is a special with a groove for the half moon locators so not available anywhere else.
BUT that isn't the whole story.
You also need to machine the shift drum to clear one of the input gears and do the same with the shift fork too.
You also have to reduce one of the input gears diameters to clear the drum as you can't take all the material of just the drum as it would leave the selector grooves too shallow..
After that you have to shim the cluster to ensure the shift forks sit central in their grooves otherwise it's possible for two gears (2nd and 5th) to engage simultaneously and destroy the motor and because of the different ratios and tooth form you also lose the kickstart function too.

It's been a while since i did the last one but off the top of my head that's pretty much it.

Oh! you also have to bore out the J input shaft at the threaded end to take the ball bearing and clutch pusher.

It's not really worth the hassle unless you are drag racing and use the Unitrack gearbox which is stronger and factory undercut which again uses a different tooth form and ratio to both the early zeds and the J..

[r3sc]

I don’t know anywhere else you could go and get that level of in depth technical information. It’s incredible!

Your skills and experience Rob are second to none and I for one am so glad that you support this forum.

[Bevelhead]

Thanks for the detailed reply.. think I'll source a A1 transmission instead.

[Bert]

I don’t know anywhere else you could go and get that level of in depth technical information. It’s incredible!

Your skills and experience Rob are second to none and I for one am so glad that you support this forum.

What he said! Hardcore for sure.

[Z1streetfighter71]

I don’t know anywhere else you could go and get that level of in depth technical information. It’s incredible!

Your skills and experience Rob are second to none and I for one am so glad that you support this forum.

Agree 100%.