What's good compression numbers??

#1
My HS40 started out as a worn out big time smoker. I rehoned and used .010 over rings file fitted. I get 70psi on the first hard pull, 95psi on the second and 105 on the third. This is a hot engine with the throttle wide open and air filter off. Im guessing this is good??
 

bikebudy

Banned - Must pay $500
#3
Most of my HS engines get 60 - 70 on first pull, they are worn and do not have new rings. They all run fantastically.

I have found that any below 60psi will not start or if they do, they run poorly.
 
#6
HOT = the engine was checked after running 10 min or so.
What did you use to determine that the engine was "hot"? (e.g., point and shoot infrared temp gun?) What was the temperature?
Just an FYI: Running the engine with the air filter removed causes a LEANER condition (more air, less gas) which WILL elevate the engine temperature.
Michael
 

MB165

Active Member
#8
Too good sounds like a broken compression release or missing exhaust bump or loose valve lash.
I hear ya.....too good....


if the valve gap is too much you wouldn't be hitting the built in bump on the cam.....maybe why they are higher than what we are used to seeing. no choke, wide open throttle is good.
 
Top