How to accurately check cylinder compression

[greg the pole]

As long as the two cylinders are close, seems to run strong/evenly, no smoke or starting issues I wouldn't worry about it. Ride it keeping an eye on oil consumption and you can retest at next major service for piece of mind.

They are close. Both batteries were in decent shape. I didn't try boosting the bikes.

 

[greg the pole]

No direct S10 knowledge to add. 8) I agree those numbers given for compression are low, low by comparison to other bikes I've had. I think they are accounting for the design, thus the low spec number. Comparative data is good too. It would be interesting to see what, if any, difference a little oil makes in your reading for the new pistons.

That said... we know the Gen 2 rings are thinner/lighter and the Gen 2 pistons are different. The crankshaft and con rods are the same, but the cylinder has been updated in some way, (interchangeable revision though) However, the cylinder heads are different and not showing as a revision that is interchangeable. 23P Vs 2BS.

Just thinking out loud that they may have manipulated the head to keep the compression ratio the same with a different piston design. Altering the combustion chamber in some attempt to reduce carbon build up or ???

That's a long winded way of saying if the bike runs well, forget about what the new numbers are. ::021::

My carbon buildup was huge. Likely due to my valve seals leaking oil on the pistons.
Bike runs very well