Compression readings

[egsols]

I'm wondering how much elevation changes the compression readings.

Crazcnuk says his bike measures 120-125 psi at 3500 ft.

I recently measured mine, I am close to sea level (800 ft +\-) and get an average of 160 psi. (42000 km's on motor)

My manual specs the min to be 128, the max to be 156 and the normal to be 142 psi (when measured at sea level)

Is there that much difference when measuring compression at a higher altitude?

[TopCatGr58]

Hey Ernie,

Believe it or not, it's been discussed before:
Compression vs. altitude thread !
T.C.

[egsols]

Originally posted by TopCatGr58

Believe it or not, it's been discussed before

I believe it and I thought it was, by my search didn't find it...I was probably searching using the word atitude which would explain the high number of unrelated results.

After reading that post Craz's numbers don't seem too low, I calculate 125 based on 3500 ft and 142 psi at sea level.

http://www.uigi.com/Atmos_pressure.html