RM250 will not kick start

[weimedog]

unless you put a little gas in the spark plug hole...then it pops first kick. It has good compression, a hot spark (new ignition), new reed valves, clean air filter....but I can not for the life of me get it to kick start cold. When hot...its a first kick starter...and it will bump start (hard) when cold.

I've had the carb apart and set the float bowl height etc. Jets are clean....

What can go wrong that I am missing?

 

[dirt bike dave]

I know you said it has new reeds, but the only time I've had that difficulty it was a (slightly) warped reed.

FWIW, I've found some bikes really like to be laid on their side before cold starting. Get that fuel really running out the overflow tubes for 5 seconds or so before picking the bike up. Kick over slow a few times to prime it, then find TDC and kick hard (choke on, no throttle or maybe just a tiny hint of throttle). If that does not work, I'm at a loss.

 

[weimedog]

You know..I do exactly that on my 1979 KTM with a bing...but I never tryed that with the RM.thanks!

 

[FatBiker]

I had to take my SP out the other day and spray it with starting fluid (it was what was handy) to clean it and then it started on the first kick. The plug was wet. I think I have a jetting issue. Is it raise the needle to lean or lower the needle?

 

[2strokerfun]

lower the needle (raise the clip) to lean.

 

[FatBiker]

Thanks. ;)

 

[whenfoxforks-ruled]

The engine is unable to pull a sufficient charge of fuel, or it is hindered somehow from drawing it into the combustion chamber. It only does it when its cold. My guesses, rings are out of spec, or the bore is slightly out of round, or the reeds are not closing.