Z1OwnersClub GB

Took the head off of one of the motor's from my GPz stockpile today. The bike had originally been turboed, so I expected to find something 'low' compression. But I found these little beauties. It appears the motor has been rebuilt, but not run for long, if at all. The oil is still clean! Bore diameter is 75mm.
Come on boy's what do you think I have uncovered

Looks like Wiseco????? Hi-comp

the head must have really deep combustion chambers
those are High compression piston's and if they were run with a Turbo
the max boost would only be a very low 5psi

swap ya fer my low comp ones.

Defo wiseco 1170cc pistons (XG on the crown denotes ring type). Wiseco only list 10.25 to 1 now in the 1170 kit but they look more like the 12 to 1's i've got under the bench.

Just had a dabble on the wiseco site & found these http://www.wiseco.com/ProductDetail.asp ... AppID=7867

The four digit code is the same, but the suffix if different

Is there a spacer between the barrels & the crankcases This would help reduce the comp ratio for a turbo.

No spacer that I've noticed, not had the barrels off yet, but nothing obvious.
My thoughts are these were perhaps fitted when the bike was de-turboed. They seem to have been hardly run. The oil in this engine is still clean!
I was wondering if they are the 10.25:1 comp pistons, would I have any trouble running them. Ie pinking, or any other complications?

I had a similar "nice surprise".E mailed Gremlin the info off piston crowns and he sent back exact spec`.

GB, take a look at my Lawson project - page 5


http://www.z1ownersclub.co.uk/forum/vie ... c&start=60


Wiseco 1170 - 10.25 : 1 in my motor

Cheers Piggy, those pistons look the same as....... Just sort yours out & I'll happily use 'em. Just don't want all that 'hanging up/spitting back grief you have had

Check the head, the combustion shape changed in later models and the wrist pin height changed as well, you may have a later head with an earlier crank and hi/comp pistons to compensate.

had a turbo technics escort rs1600i that kept detonating and eating the head so had it skimmed and stuck 2 headgaskets together and sold it

Bear, have a buthcers: http://www.oldskoolperformance.com/foru ... =12&t=1067