When good it should be around 120-125
14:1 compression
120psi
60 p.s.i.
Alot.
9:1+
150psi
It should have a minimum of 70 psi.
A yamaha blaster should have at least 120psi 150 is recommended
Compression anklets, socks, or long hose should NOT cause bruising. Most likely, the hose are too tight, too much compression. Talk to your doctor for a prescription for a lower compression product.
150psi , per. cyl. J.H
Minimum is 9,7bar.after that will run poor on low rpm.
My daughters mini bike with a 3hp Briggs has 80psi compression and runs great. A motor I got "running" off eBay has 55psi compression, runs but has NO power. -Jason