I've got my 89 kdx 200 I recently acquired up and running and was able to track down from the guy I bought it off of the guy he bought it off of and it seems just before the guy I got it from bought it it was rebuilt with a 0.020 wiseco piston and replated some mild port work annd the head was milled bt he didn't remember how much good news!so when I got this thing home I originally did a compression test and as it sat got 155psi,I then squirted a little amsoil down the plug hole since it had been sitting the guy said and it went to 185psi.I then used a borescope to look inside and it looked brand new with a quarter sized spot of carbon on the piston.well I've been tuning and riding the piss outta this bike and did another compression test tonight while cold again with the same snap on gauge as I used before and got 200psi.that's without a squirt of oil or anything in the cylinder which seems a little high to me when the books call for like 118-185psi.the only thing I can see to explain the jump would be the rings setting fully?I can't see the milling not showing up on the test before unless the motor was so fresh the rings hadn't seated yet correct?I did a plug chop and its spot on with the jetting and I ended up using a CGL jet needle 2nd to bottom clip with the 45/158 and the bike hauls ass and is a beast for 200cc's.on the trails and river this thing will stay with and even embarass my bros rm 250 (the few times its been out) unless you go for a straight line run the he's a few bikes ahead.
this ever happened to anyone else?
- Thread starter Budget_Blaster
- Start date
Blaner
Your Friendly South African Ambassador
could be that the rings had gunged up and gave u lower readings, OR your compression gauge wasnt screwed in properly the first time,...strange tho!
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