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Hard Starting when Warm/Hot - 2008 KX250F

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A good friend of mine decided to join our fun and get a bike.  We found him a 2008 KX250F for a decent price and seemed to be solid.  The original owner set it up to ride mountains (in idaho) and we will continue to ride mountains along with the St. Anthony Dunes (4500-8000 elevation).  When cold the bike seems fine, but when its hot it takes an act of congress to get it to start.  The hot start doesnt help, choke (just checking options) doesnt help.  Tried all different throttle positions and the only luck we have had is a very slightly cracked throttle, but even then it takes 10+ kicks.  Valves are in spec (well, one exhaust valve is a little tight), carb has been removed and cleaned, clean air filter.  Current jetting on the bike is 48 pilot, 190 main.  I havent messed with the air screw yet, cause i forgot about it. :facepalm:   I wonder if the jetting is too rich, but im not jetting expert. Any suggestions?

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Is the spark plug black? U could try leaning it w the air screw. I believe hard to start/poor running when hot is a running rich issue.

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my 2010 kx250f was the same way and after a month of playing with jetting cleaning carb and even trying a new carb and checking valves with no help. I tried a coil just because it was cheap and easy and it has stated with 1 kick hot every since. I never would have thought it would have been the coil.

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It might just be your starting technique.

 

I see so many people kicking 4 strokes like its a 2 stroke.

 

If you open the throttle while kicking hot you flood the bike, that is why it has a hot start to make the mixture very lean.  

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