Compression numbers from a 99 750 and a 02 620.

[drewbabich]

Just got the compression numbers from a 99 750 and a 02 620.

The compression where both done on cold engines.  I noticed that both bikes had higher compression on the the lower cyclinders.  I wonder if this has to do with oil more likely to sit in the rings or something.

Also the 620 runs great, the 750 a little sluggish, but since the 620 also has a higher compression ratio I'm guessing these numbers are acceptable for the 750?

I will also retest with warm engine later to see if there is a difference.

The 750 was :

Lower cylinder:110 psi
Upper cylinder:103

The 620 was:

Lower cylinder: 120
Upper cylinder:115