OK I'm embarrassed that I have to ask this, but can someone tell me how to convert compression ratio into PSI when checking compression. :bang: Also, does anyone know where I can get an adaptor to fit the small YZ450f spark plug thread CR8E?
sea level normal air preasure is 14.7 PSI, so I would assume its 14.7 X your Comp ratio to 1. So at like 10:1 comp ratio your like 150 PSI (147). As you go up in elevation, the air pressue will fall though, @ 3200 feet above sea level your down to 13 PSI so @10:1 your down to 130 PSI, you you need to figure and compesate for altitude if you want to be a Rich about it :D
Also thats assuming a perfect seal on the rings etc.On a 2 stroke they quote a ratio for pv shut and open-this again assumes the pv seal on the piston ring, which it doesnt.
I suppose the area of the tube and chamber of the guage depending on its ratio to the comp chamber too would lower it a bit, as far as the adaptor, I would call your dealer or check an online catalog like Dennis Kirk for someting like that. That is a small thread little plug :bang: