On early Airhead BMWs, there is an aluminum base gasket. By the mid-70's, the gasket was eliminated, and 2 o-rings were used on the top stud holes. When I work on the early ones, I eliminate the base gasket and counterbore the underside of the cylinders for the late style o-rings. This does two things-it eliminates 2 gasket surfaces, raises the compression a tiny bit, and tightens the squish band a bit. Always a happier bike.
When Norton went to 850ccs, they had trouble with the cylinders murdering the base gaskets. They worked with Loctite to develop a gasket goop that could be used in place of the base gaskets. That product still exists.
So, IIRC, there aren't any o-rings on the cylinder base. Lose the gasket and goop it up.
I believe Lancer skimmed the head and the cylinder. And used a high compression piston. Kinda tells me the bikes can tolerate a lot more compression and a much tighter squish band.
Start with measuring the squish band with the stock used head and base gaskets. Then measure the used base gasket.
In there somewhere it would be good to actually measure the combustion chamber and calculate the compression.
My guess is that the bike could tolerate about .040"/1mm of squish. If this results in a really high compression ratio, start to lose the sharp edges on the valve pockets in the piston crown.
My 2 cents.

Dave,
Was that .160" without head and base gaskets?
That's more like shoe-to-foot clearance  

Dave, thanks for taking the time to do the measurements !

Dave wrote on 02/08/18 at 03:45:38:


I hope so!!!

Armen , I might ,this guy is no joke! I first read about him in  2004 in Mechanic's Illustrated ,at that time he was just doing it to Briggs and Stratton mower engines (flat heads), but even then they produced more hp with less fuel, and ran cooler exhaust temps.(I think that could only happen with more complete combustion ) Even if the groves didn't work ,would they do any harm? I think they would only aide in what your doing by  reducing the squish zone.

Two things:
How long before the groves are full of carbon?
Are those sharp edges going to get hot in a high compression combustion chamber and provide a starting point for pre-ignition?

Armen, check out  ,Herningg.com/singh/engine , a complete test of a Geo three cylinder engine with stock head and a Singh conversion head. A stock Savage motor with 8.5:1 compression will form about 850 lbs of pressure as the piston rises , try to think about how much velocity this will create in the slot, I don't believe carbon will have a chance of forming and causing hot spots. In singh's patent the slots were v shaped, which may have caused them to lose velocity and cause hot spots ,in the motor test above they were revised( by Singh) to straight slots 3/32 wide ,starting .040 deep at the outside and increasing depth at a 4.5 degree angle as they run toward the combustion chamber. I believe this will prevent any drop in velocity and thus keep any carbon from forming.