Better Compression Numbers

[ryonker]

I finally had time to re-check my compression. BTW, don't use one of those (supposedly) helpful compression extenders. It through my numbers way off. I just hooked up the compression tester after I had driven for about 20 minutes (after taking out all the plugs of course). With the throttle open I got numbers like; 130, 125, 126, 132. I am still planning on checking my valve numbers soon.

In checking valve clearance, do you always need to replace the valve cover gasket? I know you need to let the bike sit at least over night to get accurate numbers.

Thanks!

Rick

[psyguy]

those are good compression numbers

if the valve cover gasket is lightly greased with a high temp grease it's easily removed the next time
if the po did that, i dont know

some folks use "real-gasket", a silicone permanent gasket, with good results

[Shin-Ken 1074]

Those numbers are excellent, to be that close and in that range you have no need for concern there. As for the valve train, yes it must be cold, or at least very cool to check, not even warm to touch with your hand for accuracy. I usually get two uses from the tappet cover gasket and then replace it on the third time it comes off, depends on how true the mating surfaces are and the torque applied. Sometimes one use is all you get. Love those barrel numbers hope mine are that good! Cheers.

[flyingace]

I finally had time to re-check my compression. BTW, don't use one of those (supposedly) helpful compression extenders. It through my numbers way off. I just hooked up the compression tester after I had driven for about 20 minutes (after taking out all the plugs of course). With the throttle open I got numbers like; 130, 125, 126, 132. I am still planning on checking my valve numbers soon.

In checking valve clearance, do you always need to replace the valve cover gasket? I know you need to let the bike sit at least over night to get accurate numbers.

Thanks!

Rick

I must have reused mine at least a dozen times - and it was probably stock. It never leaked once either. I finally had to replace my valve cover and went to real gasket.

I wouldn't replace it unless it leaks. But I tend to be a low budget GSer.