gsxrjarrett

Hey everyone. Real quick question i need some help with. I have a 03 XR50 that wont run. I also have an 04 Crf50. I compared the compression on them yesterday and have about 60Psi on the XR and a little over 90 on the Crf. First off thinking rings of course. It ran fine up until recently but now won't start. Both bikes are bone stock (less baffle's in pipes).

Any advise ?

Thanks,

GsxrJarrett.

kdog22

Could be a number of things but the piston rings would raise a flag here. Check and make sure you have spark and that the spark plug cap is set on there right (stupid, i know, but i've seen it before). Make sure you go a clean carb and air filter and fresh gas. Give your bike every opportunity to fire up and run before you start digging into the engine just incase it's something little.

gsxrjarrett

Well belive it or not it turned out to be a real weak spark. I swaped plugs and the XR fired up and runs good. Still concerns me about the difference in the compression. I'm goona check the valves soon as this may cause it ?

GsxrJarrett