compression readings

[awolxt]

Hi !

Anybody got compression readings for a 2003 xt600e i can compare mine to?

According to the service manual for the older model it should be around 156 psi

Mine is 180 psi warm and cold engine, these are higher than the maximum of 171 psi from the service manual.

Bike runs well , are these readings acceptable or is there an underlying problem?

Cheers
Bill

[xtrock]

Sounds a bit strange to me that you have same compression cold and warm, if the manual says 171 the accuracy on the compression tester maybe not the best? Are you sure there was no fuel coming into the engine, turn of fuel line and run empty first.

[steveloomis]

My 86 xt with 10000 miles showed about 170 lbs with a new compression tester. Manual says 128 minimum, 156 nominal, and 170 maximum. Your readings of 180 can be a gauge that is not calibrated exactly. There is NOTHING that will make too much compression so be happy it is a high reading and greater than nominal.

I have just rebuilt a top end on another bike with new rings and a honed cylinder. I am anxious to check it once the rings are seated, I have not checked it yet but have had it running.

Steve

[awolxt]

Hi guys!

Because the bike is running well i was fairly happy, but thought id get some other more knowledgeable peoples opinions. Last time i used the guage was about 20 years ago, so i dont suppose it would be quite accurate. Thanks for the help xtrock and thanks steve for putting my mind at rest!

Btw i didnt drain the fuel supply pipe xtrock, how does this alter the readings though? All i did was leave the fuel tap off.


Bill

[xtrock]

When you open full throttle and get fuel into cylinder the compression reading can rise up.

[awolxt]

Ahh i see, never considered that! Ill give it a go tomorrow with the tap off and pipe drained.

Thanks again!

Bill

[xtrock]

Originally Posted by awolxt

Ahh i see, never considered that! Ill give it a go tomorrow with the tap off and pipe drained.

Thanks again!

Bill

Yes but you need to run the bike till it stops for empty carb. And check how much the first puff gives, compared to the fifth.