[remedy08]

Hi all,

I'm new to the forum, but I'm sure I'll become a regular, as I finally decided to start doing my own repairs and maintenance, instead of paying someone else to do it. It makes the sport even more interesting. Anyway can someone help me out on the compression specs for my bike. I checked the compression and it is at 90psi, I just can't find any place that shows what is the correct compression. I just reshimed the bike to specifications, but it won't start, valves and springs seemed to be in good shape, and I have never had issues with the carb.

Thanks all for your help!

[crfsonly]

welcome to CRF's Only. stock compression is 12.5:1. when changing pistons you should consider increasing the compression if you are looking for more torque.

ken

[remedy08]

Thanks Ken,

I was hoping to find out if the 90PSI that i got from a compression test that I did is good, or if I have to replace perhaps the piston rings. The issue is that my CRF overheated, and now is not starting. First thing I did was to check the shims, and now they are up to specs. I also changed the spark plug since it was a bit old, checked the timing. It did start for about 5 seconds, but after that, I haven't been able to start it again. I am thinking maybe the compression is too low.

[crfsonly]

You need to do a leak down compression test to get the correct reading. if your valve clearances are in spec then verify the timing. if clearances and timing are correct then look to verify spark. if you have spark then make sure you have fuel. check AP squirt, replace pilot jet, and clean main jet.

report back

[remedy08]

thanks!