Kawasaki ATV Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
3,550 Posts
Discussion Starter #1 (Edited)
Just like the title says, ran a comp test today. Came back kind of interesting. Front cylinder was 77 psi, and the rear was 80. I've never seen them that high before. Last time I checked it was a couple hundred miles after I put the new valve seals and (un-needed) front piston in, and the front was 61 psi and the rear was 52.
I'm not complaining, but certainly wasn't expecting what I saw.?
Front piston now has about 2000 miles, and the rear is about 11,000.
They are 11.5:1 compression pistons.
Thoughts?
 

·
Super Moderator
Joined
·
12,552 Posts
11:1 pistons will account for the higher compression.
The difference from last time could be simply checking it when warm, forgetting to hold the throttle open while doing the test, etc.
 

·
Registered
Joined
·
3,550 Posts
Discussion Starter #4
11:1 pistons will account for the higher compression.
The difference from last time could be simply checking it when warm, forgetting to hold the throttle open while doing the test, etc.
Lol, I did forget to hold the throttle open once, but not the last time I ran a test. Temp was hot both times too.
 

·
Registered
Joined
·
728 Posts
Didn't you just get a valve job a couple months ago? Leaky valves would account for the difference.
 

·
Registered
Joined
·
3,550 Posts
Discussion Starter #6
Didn't you just get a valve job a couple months ago? Leaky valves would account for the difference.
Yes, they surely would. But the valves were still good when I ran the test, I think. I'll have to go check the notes and dates in my log book.
 

·
Registered
Joined
·
3,550 Posts
Discussion Starter #7 (Edited)
Well, looking at my log book and then my receipts, I see I ran the last test after my piston and valve seal job, but before my vfj valve seat cut job. It appears I didn't run the test after I got the new seats and valves. I also forgot that they found two valve guides (one in each head) that were a tad loose, and they ordered and installed those before I dropped off my other goodies.
Thank gawd I keep good notes because I totally forgot they did that!??
Well in any event, I like pleasant surprises like that. I'm glad they are looking good now.
 
1 - 7 of 7 Posts
Top