what compression numbers should I be looking for with a head gasket mod? I was a little suprised last night at 9000 miles I have 129 psi (cold) on all 3. I was expecting it to be lower but how much does the head gasket mod bump the compression? first time I ever bothered to check it.
daman
New member
9k....i'd be re-ringing and checking spec on them pistons,that alot of miles
if it's stock yet.
if it's stock yet.
Alot of guys will say that the number you get is subject to your comp tester. Being some testers may read higher/lower. The good thing is that they are equal. Can't help on the other questions.
dnale said:
I tried 2 guages because that exact thought came to me. They both read 129 on the digital and regular guage. I am going to rering it as I have never done it and I am definitely going to mic it. anyone got specs on the pistons?
daman
New member
BBlueSRX said:
Not shure on the specs somone will jump in
but post back with your findings.....
NORTHMANSX
New member
Your compression is fine at 9k, thats only 5000 miles.Every tester will read different but if you got two that read the same thats good. Mine with 9400k reads 134psi. I think you could expect about 5 psi for every layer of gasket you remove. I would not rering unless you have it apart and/or you have low compression.
Do you think every guy that rides at polaris rerings at 5000 miles, i don't think so.
Do you think every guy that rides at polaris rerings at 5000 miles, i don't think so.
135 is about what a 97 sx(same motor) would show with the center layer removed. I'd say those are really good numbers. Maxdlx
yo northman... thats 9000 miles not KM. anyone with specs on the pistons?
NORTHMANSX
New member
oops, that definatly makes a difference. i guess i would do like your talking about and measure to see what the clearances are.
daman
New member
BBlueSRX said:
If no one jumps in give your dealer a call, i'm shure they would help ya...
Piston Specs
The cylinder bore should be 70.5 -70.52mm (2.775" - 2.776") Taper limit should be no greater than .05mm (.0019"), Out of round limit should be no greater than .01 (.004"). Tracy
The specs for the 700cc from the manual call out to measure the piston up 15 mm from the base or end of the skirt and measure from Front to back of the piston (exhaust side to the intake side). Diameter should be 70.425 - 70.430mm (2.7720" - 2.7728")<-- NOT a typo. Piston to cylinder clearance should be .070 - .075mm (.0028" -.0030").BBlueSRX said:
The cylinder bore should be 70.5 -70.52mm (2.775" - 2.776") Taper limit should be no greater than .05mm (.0019"), Out of round limit should be no greater than .01 (.004"). Tracy