Bigbore

[Steve R]

My Z1A has z1000 barrels and pistons. I know when you fit 1075 wisco pistons to a z1 you need to open up the holes on top of the top crankcase.
So my question is since I already have z1000 barrels on will some one have already done this? And therefor can I now bore out to 1075 without having to take the crankcases apart?
Any one know?
Regards Steve R

[Rich]

you should already have the crankcase opened out for the 1015 barrels and the 1075 is a straight rebore for the barrels.

[hanskloss]

I have 1015 barrels on my Z900A4 now and they fitted straight in with no mods to the cases, I recently bought 1075 wiseco kit with bored ex1015 barrels and that will just bolt on, all the Z1 cases should be the same I guess, I know you can not rebore 903 barrels to 1075 but that is because of cylinder liners not the crankcases

[Jeff Saunders]

Some 900 crankcases accept the 1015cc barrels fine - others require a small amount of clearance help to get the sleeves to drop into the cases.

[Garn 1]

Agree with Jeff, I have heard of some 1000 sleeves dropping in to 900 cases and others that require removal of metal from the top case. I seem to recall the earlier Z1 cases need no modification (metal removed).

In any case Steve, (excuse the pun) if you have 1000 barrels in your Z1A then the job has been done or doesn't need to be done! Feel free to bore out your existing barrels

RegardZ

[Steve R]

Excellent ,
Thanks guys, now its just down to the usual problems Time and Money!

[Pigford]

Surely, a thread with this title 'BigBore' should contain the main subject - Paul Doran!? :p