Have a 02 yz250f with 03 cams and athena 290 kit.the problem is it dont want to start at operating temp valves are in spec!what else could it be
Going crazy
- Thread starter dwaynemichael
- Start date
I need to pull the carb and check
if it starts decently cold, and doesnt when it is hotter look for an overlyrich condition. being about 12 years old and probably not having the float set since the carburetor left the factory, it is where I would start. the condition gets magnified when you put a stronger vacuum to the existing carburetion. warmer weather, more vacuum, etc etc.
i havent bought an athena kit for a 4 stroke, but they were vague on two stroke suggestions for actual jet sizes. going to an 82 mm piston on my crf (rpm kit) didn't need a change in actual brass, for startup anyway. (hot or cold)
Most companies are schooled well enough by the other conditions listed not to go out on a limb with an actual jet size. For my 4 strokes since time started for me I learned that when you shut one off, I turn the fuel off before I kill it. Fuel expands greatly and you can boil it in the bowl really easily once you shut the engine off and there is no air movement. Fuel comes right up the fuel passages and runs right down into the intake area and if the valves are closed gathers there and tries to evaporate. If it does dry up you usually dont have a start up problem. On the other hand if you try to start again in a shorter period of time, it is too rich.
Makes it worse when you have a years old rising fuel level due to the way floats go out of adjustment.
i havent bought an athena kit for a 4 stroke, but they were vague on two stroke suggestions for actual jet sizes. going to an 82 mm piston on my crf (rpm kit) didn't need a change in actual brass, for startup anyway. (hot or cold)
Most companies are schooled well enough by the other conditions listed not to go out on a limb with an actual jet size. For my 4 strokes since time started for me I learned that when you shut one off, I turn the fuel off before I kill it. Fuel expands greatly and you can boil it in the bowl really easily once you shut the engine off and there is no air movement. Fuel comes right up the fuel passages and runs right down into the intake area and if the valves are closed gathers there and tries to evaporate. If it does dry up you usually dont have a start up problem. On the other hand if you try to start again in a shorter period of time, it is too rich.
Makes it worse when you have a years old rising fuel level due to the way floats go out of adjustment.