Compression Test - Snowmobile Forum: Your #1 Snowmobile Forum

yamahabob · 02-05-2005, 06:03 PM

Today i went out to the local canadian tire and baught myself a compression tester. As it doesne exactly tell you how to use it for a snowmobile, i put it on and gave it 1 pull and looked at it and it said 90.....i thought this was kinda low so i pulled it again to see what would happend and it went up to 120 and wouldlnt go any further.

Is this the proper way to check compression? I hope it is because i hope to hell its not 90.....

**smallengineguy** · 02-05-2005, 06:25 PM

Give it full throttle and pull it 3 times to check it correctly.

yamahabob · 02-06-2005, 11:55 AM

ok, so my compression turns out to be 120 on both cylinders.......my sled is a 99 yamaha v-max 600 twin with 7000 km on it.......what do you thik about the compression?

Snow Freak · 02-06-2005, 11:56 AM

Well SEG always says anything under 120 is low, so it sounds like you are good to go!

yamahabob · 02-06-2005, 12:16 PM

Ya, i think i remeber him saying that in another thread now that i think of it......
I stumbled upon something interesting on the net today.....aparently the 600 twins from 96-99 have poor compression from the factory due the the 1.4mm head gasket.....lucky enough i found http://www.maxxperf.com/Vmax_Twin_Gaskets.htm this website which sells a smaller one that increases compression quiet a bit..the gasket comes in .6 mm that need 91 octane fuel minimum or .8 that i can run regular fuel with...for $40.00 its sure worth the try and i might as well replace the exhaust gasket while im at it......

**smallengineguy** · 02-06-2005, 12:17 PM

That compression is good! They'll run OK at 110 or so, but 120 is what you're looking for.