Z1OwnersClub GB

Quick question folks. I'm just about to refit the cylinder head on my gpz11 with the 1135 big bore kit and I was wondering if the four "o"rings that sit in the barrels on the outside studs should fit under the head gasket or do they sit through the head gasket? The outside 4 holes in the new Cometic head gasket I've got are 12mm diameter and it looks from pictures that the standard head gasket holes are a larger diameter so the "o"rings sit through the gasket, anybody know which way it should be? And should I just enlarge the holes in the new gasket so the "o"rings sit through ?
Cheers
Rich

The four 'O' rings go under the gasket. Reason for the bigger holes is to allow some oil through there for the head feed. The 'O' ring fiasco is a failed concept. Dont bother with them. If you want to use the fibre Cometic gasket get four 'Machine' washers (the type with a bevel on one face). Put them bevel side up with a tiny smear of silicone sealer beneath them let it dry first. Part of the head gasket will press down into the annulus created by the bevel and form a type of 'matrix' seal.
You could do yourself a big favour instead. The Cometic fibre gaskets are another failed concept. You will spring leaks before 500 miles and have to tighten the head nuts five times at least 'till it compresses enough to seal. You will also need to go to 39 lbs/ft of torque (marginal with standard studs) which also overloads the threads in the crankcase.
If you can; get yourself the new replacement MLS gasket, fit it, torque it and forget it.(i hear it can be re-used too but cant confirm as i've never done it)
Available from; Debbens, Grumpy 1260, etc, etc, etc for 1170 at least, so hopefully fit for, or available for 1135cc too.

AL

Cheers Al, I'll give that a try, think I've got some machine washers knocking about, I was just a bit concerned about squashing the "o"rings a bit too much and restricting the oil supply.
Cheers
Rich

Just found this after a quick search
viewtopic.php?f=4&t=324&hilit=92055+1148
So it may be that I have to omit the "o"rings with a Cometic gasket.

Sorry, forgot to mention scroll to the bottom of the thread