2000 KX 250 Won't Start

[wills4nv]

I recently bought a 2000 KX 250. It was freshly rebuilt, both top and bottom ends. I took it for about a 30 mile ride just after buying it. Ran the carb dry after washing it and put it away. Decided to start fixing it up and over the past month I installed a new Boyesen water pump, clutch and mag covers. re packed the pipe, put on a Clarke desert tank, and a bunch of other cosmetic stuff. So I have a ride planned next weekend and go to start it and it won't even try to start. I took the carb apart, cleaned it and put a new plug in and nothing. Seemed to have good spark however I bought a new coil and a carb rebuild kit. Changed the main jet, pilot jet, air screw, needle and float jet. Set the air screw at 2 turns out. Once again nothing. I check the spark last night in the dark and it is blue and seems strong. I am stumped. Thoughts????

[WR250F]

How's the compression? Check and see if the top end gaskets are in good condition. Did you rebuild it or a shop. Pull the head off and check the piston,rings and cylinder condition. I had an RM 125 that run one day and not the next. Did all the checks and pulled the head and found the cylinder with a deep groove. Check the flywheel for loosening and woodruff key.

Edited July 19, 2015 by WR250F

[Westoz_]

Spray some crc or fuel through the spark plug hole and see if it fires if not it could be the stator or could be something to do with the float level as well

[wills4nv]

After checking the compression and everything else suggested I brought the carb and had it dipped in a ultra sonic tank. Blew it out with compressed air and the thing started on the first kick. I really thought I had cleaned it thoroughly however that wasn't the case. Thank you for the tips. This was a great learning experience.

[turbo dan]

Some of those tiny passages in the pilot circuit can clog with varnish or debris.  You may want to install a fuel filter or clean out the gas tank.

[Scooter1m]

Def install a fuel filter,I got one on each of my dirtbikes

[wills4nv]

It's really tight with the new Clarke desert tank I put on it.