Squish Test on Tri Z good or not?

[1972mercury]

I'm doing a total rebuild on my Tri Z engine and since I shaved the head .5mm I did a squish test to see what it was this is my first time doing this found this website how to do it http://gasgasrider.org/html/measuring_squish.html so I did the solder test twice to make sure and with the shaved head I'm getting 4mm (0.157) I bought a full Athena gasket set it came with a 3 piece metal gasket the Yamaha wrench report said a minimum of .75 Will this run okay yet or do I have to get it lower?

[RIDE-RED 250r]

OK, I figured out what you are saying... sorry if my initial post was misguided....


From the sound of your measurements, you still have too much clearance, and by quite a bit...

I would try to get it down close 1 layer at a time with the 3 piece gasket....

According to a conversion calculator, .75mm equals .030". And you are currently at 4mm or almost .160". I don't know how thick each layer of your gasket is, but I would try to reduce the thickness by about .120" if possible. I would rather have about .010" safety margin than be right at the minimum squish. When you re-torque the top end after a couple of heat cycles you might be right at the limit....

[1972mercury]

OK, I figured out what you are saying... sorry if my initial post was misguided....


From the sound of your measurements, you still have too much clearance, and by quite a bit...

I would try to get it down close 1 layer at a time with the 3 piece gasket....

According to a conversion calculator, .75mm equals .030". And you are currently at 4mm or almost .160". I don't know how thick each layer of your gasket is, but I would try to reduce the thickness by about .120" if possible. I would rather have about .010" safety margin than be right at the minimum squish. When you re-torque the top end after a couple of heat cycles you might be right at the limit....

Yeah I just went out in the garage to measure the head gasket I had the old one yet which was the same thing a 3 piece metal gasket that was 2mm thick then I measured my new one that's 3mm but from that website they say to snug tighten the head so that's why this new one is just a hair thicker.

[RIDE-RED 250r]

I would definitely give myself a little leeway then....

I know that there is not a "1 size fits all" universal squish spec for all engines. They are all a little different based on the design of the squish band. But I would certainly make sure and not have less than the minimum squish clearance... That will jack your compression and give you all sorts of headaches... Better to be a little bit more clearance than the minimum...

Did the wrench report list a max squish spec?? Just wondering what the ideal working range is....

If they list a max, then I would try to shoot for the middle.... Just my opinion....