2018 compression numbers

[DKP]

Just wondering what these came as new, broken in, for compression? I just got a good tester, finally tested mine 120mag 121pto 4500Km MTN riding. Wondering how much she dropped off? I know I should do top end. But what was the starting point? tested at 1200ft elev. cold engine as well

 

[mtncat1]

compression on a 2 stroke motor is quite abit lower than on a 4 stroke 120 is not a bad number , but altitude makes the numbers vary a lot .

 

[seef158]

I'd buy a leak down tester, cheap on Amazon. You can also get a look at pistons by pulling exhaust valves and y pipe

 

[Spiderman]

Just wondering what these came as new, broken in, for compression? I just got a good tester, finally tested mine 120mag 121pto 4500Km MTN riding. Wondering how much she dropped off? I know I should do top end. But what was the starting point? tested at 1200ft elev. cold engine as well

My 850 with 500 miles had 120 on both with engine cold at the same elevation which I think is average for a cold motor.

 

[gtwitch]

My experience after 20+ years here in Laramie at 7200 ft is a 2% drop in compression per 1000 ft in elevation and like said other places do, Use a L:eakdown tester, I have done this on aircraft engines for years also
gtwitch in wyoming

 

[DKP]

Yeah. 3 rides after. The pto rod decided to escape the asylum through the basement. Got picked up by the feds in the belly pan. Good news. Still have warranty on my 2018!!!! So new motor!!!!!