[yev121]

I have a 2004 crf250r that I just put in new kibblewhite intake valves and set all the valve clearances. The bike starts when the carburetor is completely drained (hard to start if its not drained) within 3-5 or so kicks. Once it gets running for a few minutes and I shut it off, its nearly impossible to get started back up even with the hot start lever. I just replaced the head gasket as well and cleaned out the carb which has stock jets. Any ideas what maybe causing this issues? My only guess at this point is either my mixture screw or idle screw isnt set properly.

[JimDirt]

Welcome to the site !!

We have a carb expert here , hopefully leardriver will chime in , but in the meantime , some more details are needed ..... I am guessing the bike sat for a few months ??? , less/more ?? , , also when you "cleaned" the carb , did you spray carb cleaner in it ??? , if so where ?? , and was the carb completely apart when it was cleaned or together ?? , it is possible that the O-Ring for the fuel screw was compromised and that is allowing the mixture not to be able to be adjusted .... it is also possible that the needle/seat , is damaged and the carb is flooding (does gas drip out the overflow tube ??) ....... Did you adjust the fuel screw at all (did you remove it ??) , if you removed it did you get the O-ring and washer installed correctly ??? , also what did you set it at ?? (turns out from gently seated) , are you sure all the jets are not loose ??

There is no reason the carb would need to be drained of gas to "lean " the mixture , so either there is a air blockage only allowing large amounts of fuel without air to atomize ..... or ..... the fuel screw is set wrong or the O-Ring for it is compromised , or , the bowl is draining into the intake because of a float issue and its actually flooding the engine (check to see if there is a gas smell in the oil by smelling at the oil filler cap (with it off) and/or draining the oil and smelling it or seeing if there is more volume than you put in , indicating fuel going past the rings from the cylinder filling with gas and it drains into the oil/crankcase ...... Those would be my first guesses ...... hopefully leardriver chimes in soon and can give his knowledge input .....