View Full Version : Compression test

9th February 2008, 13:54
Anyone know what compression test readings to expect from a FZ 250 Yamaha. It's an older model '89' I think, but in immaculate condition. Cheers Steve

13th February 2008, 13:48
Don't know it sorry, i'm sure you already know this but anyway

Since its a multi cyl you can still diagnose problems by the difference in pressure between each cylinder. Do a test and if you have one thats out by more than 15-20psi then you have a problem, if they're all the same then look around and work out if its low across the board or not.

Why do you think it's down on compression if you don't mind me asking? :Punk:

13th February 2008, 17:59
I'm told that as a general rule, you want at least 100psi. Same source says consistency is key, you don't want more than 10% variation across the cylinders.