Trouble Starting CRF250 with high compression piston plz help


May 9, 2007
Ok about a month ago i bought a 2004 CRF250 and it has all sorts of after market parts like white bros exhaust and high compression piston. I finally got the starting of the bike down because its harder but sometimes like after a fall or i dont put my bike into neutral when i turn it off it wont start up again for like 15-20 mins of kicking it. I called the guy that i bought it off of and he said he didnt ever have a problem with it and said it might be flooded. so i turn the gas off tip the bike over and let the gas drain out of the carb and it still has trouble. Is there something wrong with the bike or am i doing something wrong i do all of the maintenance things like air filter cleanings chainlubing etc.?


Jan 27, 2000
Like the guy said, you are flooding it. When you drop the bike and pick it back up, turn the throttle wide open and hold it there. Kick the bike over about 8 to 10 times and then release the throttle and try to start it. This will clean out a flooded engine. Do not work the throttle or it will flood it again.

Do a search. There is a lot of information about how to start your four stroke.

Also, if you haven't done so already, check your valve adjustment. A tight valve will make your bike hard to start.


Oct 21, 2006
did you jet it?- you changed the exhaust- that changes the back pressure on the cylinder,
higher compression = more atomized air to fuel- it should start easier
what does the plug look like-
black,and dry= not enough air-
wet -too much fuel
if the float level is too high, the fuel will run into the cylinder when tipped this floods bikes
do you have to choke the hell out of it when you first start it?
if so a size bigger pilot will help-
if its jetted - it might be too rich- this might be the problem - since you said it has all kinds of stuff done to it- it sounds like someone else did all this stuff??? not you?

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