Not enough compression to start..250X

Hey i have been having a problem with my 250X, when i try to kick it over when it is cold it will not start, it is right on the verg cause it will pop a few times like it is going to go but then it dont. i have a race in 2 weeks so we are franticly trying to figure out y it wont, when we pop start it, it will fire right up with no problems at all, it hard takes any thing. it all so will not idle at all either? we got a race april 7th so any help is greatly thanked, i do not think that it could be the pistons cause i rebuilty it about 4 years ago but it might be?

Check the regulars. Spark plug, air filter, ...etc. It is possible that the rings are shot and there is no compression. Do you feel a lose in power or is it burning oil? Both of those are signs. It could be an electrical thing too. Try to clean up the contacts and spray some wd40 on everything.

if the rings are bad do u think that could be y it wont idle?thanks

Have you tried to turn up the idle. I had to on mine when it got cold out.

Start with the basics. Good blue fire at the plug, run a compression check next. 160 pounds +/- 20 psi. Plug wire off, choke on, kick over a few times, pull plug, is it wet? It should be. Make sure the valves are adjusted correctly if compression is low before you tear into it. good luck.