OzVMX Forum

Marque Remarks => Yamaha => Topic started by: dave on July 23, 2009, 06:35:48 pm

Title: XT500 compression testing spec's?
Post by: dave on July 23, 2009, 06:35:48 pm

Could anyone please give me the spec's for a compression test of an XT500, in p.s.i please.

Title: Re: XT500 compression testing spec's?
Post by: brent j on July 23, 2009, 10:41:48 pm

My manual says,

9.5-10.5kg/cm2 or 135-149lbs/in2 at kick starting.

It doesn't say how many time you should kick it though, I usually kick it til the needle stops rising.

hth

Brent

Title: Re: XT500 compression testing spec's?
Post by: TT5 Matt on July 23, 2009, 11:18:28 pm

and at wot [wide open throttle] with the motor at running temp

Title: Re: XT500 compression testing spec's?
Post by: brent j on July 23, 2009, 11:24:13 pm

yeah good point

Title: Re: XT500 compression testing spec's?
Post by: dave on July 24, 2009, 07:06:01 am

Oh so 55psi probably isn't real crash hot  :-\

Title: Re: XT500 compression testing spec's?
Post by: brent j on July 24, 2009, 01:00:18 pm

A bit on the low side yeah..............

Try some oil in through the spark plug hole then test it again, if the compression improves it's most likely rings.

Check your valve clearances and the decomp lever is free.

How well or badly does it run does it run?

Title: Re: XT500 compression testing spec's?
Post by: dave on July 24, 2009, 01:18:22 pm

It ran ok several months ago but not brilliantly. Didn't blow lots of blue smoke. It has been sitting for a while. Hey Brent 55psi was after the oil went in mate  ::)

Title: Re: XT500 compression testing spec's?
Post by: brent j on July 24, 2009, 02:56:07 pm

Oh...............

Title: Re: XT500 compression testing spec's?
Post by: dave on July 24, 2009, 04:25:46 pm

Hey Brent thanks for the spec's, looks like I'll be doing a teardown this weekend. Cheers digger