'03 YZ85 compression check
- Thread starter deadhead
- Start date
DKM Factory
Member
- Jun 29, 2004
- 4
- 0
Usually the bikes I work on are 160+ with a fresh top end, if 150- time for rings or a top end kit
Jasle
Sponsoring Member
- Nov 27, 2001
- 1,358
- 1
what I do is check the compression when it has a new topend...then recheck it periodically and when it gets below 90% of the original value then i do rings and check the piston. I have found that different gauges give radically different readins. I have seen one say 150 and the other say 115 on the same motor within 5 minutes of each other.
Also make sure your checking with the throttle wide open
Also make sure your checking with the throttle wide open
poffracing
Member
- Jun 4, 2004
- 2
- 0
I just put a top end in my son's '04 YZ85 last week. I checked compression last night and it was at 155lbs. Hope this helps.
- Thread starter
-
- #6
Jasle,
I agree with your approach. Unfortunately, I only recently purchased my compression tester. Had to have one.
The owner's manual for my son's old KX65 gave a psi range. I think it was 155 to 171 psi. I can't find one in the YZ85 manual.
deadhead
I agree with your approach. Unfortunately, I only recently purchased my compression tester. Had to have one.
The owner's manual for my son's old KX65 gave a psi range. I think it was 155 to 171 psi. I can't find one in the YZ85 manual.
deadhead
