Im not sure you should go by just a number like 120,130..etc. Every compression gauge I have ever used has always shown a different number and two of mine (decent quality) are off about 15 pounds from each other. The only time you can safely use the numbers on your gauge is when you have another known good (fresh/new) engine to take readings against.
The best rule of thumb to go by is to take the measurement on a cold engine, then take it again on a hot engine. This is what Dynamo Joe (Has great clutch kits, and great to deal with) has to say about it.
Taken from www.mxzx-revzone.com
"Take a Cold vs. Hot compression test.
1] Start the sled and let it run for about 30 seconds and kill engine.
Take compression with 6 pulls at wide open throttle.
What are the values?
2] Start the sled and let it run until the coolant is at operating temperature and flowing. Go take it for a run if you can and out there when engine operating temperature, shut it off and check the compression with 6 pulls at wide open throttle.
What are the values?
It does not matter if your gage is accurate or not as long as you use the same gauge when cold vs. hot temps.
Indications of rings going bad:
cold compression - 5lb(35kpa) or greater difference from mag to pto.
Hot compression - 7lbs (48kpa)(or more less than when it was cold then you need rings.
Hot compression - 10lbs(68kpa) or more less than when it was cold then you need pistons.
Example:
Cold @ 145lbs (999kpa)
Hot @ 138 lbs (951kpa) or less than...
Value difference more than 10lbs (68kpa)"
The test should tell you the real condition of the motor. Too much difference between jugs = bad, and too much difference between hot and cold = bad....Im sure you get the point.
Besides the standard REV pre-purchase checks...Do a search on 800r, Im sure you'll find plenty of reading material. Be careful though, you will need to sift through some crap to find the good. Dont let anybody tell you they are crappy machines, but some had some issues.
The biggest things with the 07 800r that most would agree on...IMO
Stock track sucks, some like it but most dont.
Enough crank/engine failures for Doo to offer a free 2nd year engine/clutch warranty. (check behind the torque stop for an "R" stamp in the case. These are the "better" replacement cases for the ones with tight tolerances)
Clutches had some issues with rollers, bushings, helix sizing, rollers, bushings, rollers, bushings...etc.
If your a guy that likes to tinker and spend some time to tune and dial it in, it could be a great sled. Some guys claim to have never had any issues, many others claim to have all the issues. Ive had my fair share (07 XRS) but mine has turned out to be pretty good overall, and a blast to ride! I wouldnt trade it in on an XP right now unless It was a straight across deal.
These are my opinions, and if you dont like it.......
Do some research, and you'll come to the right decision.
Joe
