Check valve clearance with engine at TDC. (Compression stroke) Intake .006" (.15mm) Exhaust .010" (.27mm) +/- .0019" (.05mm) Engine cold.

later[img]i/expressions/face-icon-small-wink.gif[/img]

 

Finally an answer, I picked up a good compression tester and dry it had 30 [img]i/expressions/face-icon-small-mad.gif[/img] then I did a wet test and it came up to about 120. Time for a piston and rings or at least bare minimum just rings. Oh well that is part of the sport????? This is what I was afraid of.

 

This engine has built-in decompression components. Compression readings will vary in proportion to cranking speed during the test. Average compression is about 85-90psi@400 RRM. A smooth idle generally indicates good compression. Low engine compression is rarely a factor in running condition problems above idle speed. Abnormally high compression can be caused by carbon depposits in the combustion chamber or worn, damaged exhaust cam lobes.

later

 

Wouldn't 30 be excessively low even considering decompression?

 

Again, everything you have said is the same as my brothers Z-400. He had only 25lbs of compression. He thought it was his piston or rings too. He was about to take the top end apart when I talked to a Suzuki mech, and he said it sounds like you jumped a tooth in your timeing. We checked, and sure enough, it was off a tooth. It might be worth a look before you take it apart. Just a thought.

 

well i beleive you need a valave adjustment. i'm a polaris certified master tech. and we have been running into problems on the predators with the valves getting stretched from hard break ins.and poeple over revving them severely.
your best bet is to take it to a dealer or if you're capable set the valve clearance at 4 thousandths between the cam and the bucket @ TDC. you will need to get shims from your polaris dealer.

 

killerkx327, I allways thought that a wet test would only seal the rings???? But now that you mention it when doing the test I did notice oil misting out of the carb mount (the carb was off during the compression test). The weird thing is that I can rotate the buckets so there cannot be that much tension on them????? Also, will a modified airbox void the warranty?

 

well get the valves adjusted, as that needs to be done anyway, then check timing as well.you should never have to pull start a quad. and it's hard on the motor as well. so i don't recommend it. how old is your machine? if it's still within 6 months get it covered under warranty.

 

When my wife bought the bike she bought the extended warranty and the maintanance agreement. They said that it would cover the major services and mechanical breakdowns???

 

so my 2003 predator is doing the same thing....it has thirty pounds of compression cold and 95 when its warm.....its starts and runs fine. when i bought it the guy told me that the battery was dead from setting for awhile. we pull started it and drove it for a while and had no problem when the motor was hot. three years later and it still will only pull start. ive had it at a few different shop and still cant figure it out. the guy i bought it from said the local polaris shop rebuilt it 10 hrs before i bought it. any suggestions?