780/925 Compression solutions

[Sako7STW]

I have a 780 that has been bored to a 925. It has some really high compression and I have to run atleast AV gas. I want to take the compression down some to run premium. I can stand to loose a few HP to save 60% on fuel costs.

I was thinking about stacking head gaskets? You can make them seal if you do it right. What other things would work? Withought a complete top end rebuild.

 

[DWHalverson]

There are no head gaskets on those engines, just O-rings in the head. The base gasket can be varied. Ski-Doo makes ones that are different thickness, so you shouldn't have to stack them. If you already have a thick one installed then a call to Mike Sauer @ Cometic Gaskets would be the next place for a custom one. They are cheap and have fast turnaround. The first thing you need to do is mic out the one you have to find out it's thickness.

 

[triple7]

What he said, or you could machine the dome. Alot of times you can remove material from the head dome to create a more 'soft head' type chamber and actually gain power while allowing you to run pump gas...just a thought