2009 kx450f hesitation?

My 2009 FI hesitates and is slow on the power in 1st and 2nd gear. Fine in 3rd and up. Any suggestions on what it could be? FI unit?

Is this a new bike? How many hrs.

Without knowing much more info then whats posted, Check the easy things. Is the air filter clean, How old is the gas, water in the gas, how old is the spark plug, etc. Go through all of your general maint. before getting into the meat and potatoes. I have a F/I bike and have not had to touch it. I do have a Dyno Jet P/C 5, but having that or not should not effect your bike.

Probably 100 hours on the bike, new gas, new plug, valves and timing are good. Electrical is all hooked up, no water on it. Gaskets are all good, no pinching cables, good top and bottom end. have not checked stator and I do need to clean the air filter.

This is a new issue, right? What happened between when it last ran properly and when it ran poorly. Did it:

Sit a long time?

Get washed?

Fuel tank filled with Mexican gas?

Slowly got worse over time?

This is a new issue, right? What happened between when it last ran properly and when it ran poorly. Did it:

Sit a long time?

Get washed?

Fuel tank filled with Mexican gas?

Slowly got worse over time?

Forgot to mention that i have never had it running, bought it with a shot crank. Had it repaired and reinstalled by a certified mechanic. It took about a month between the time it broke to getting it running.

Have not washed anything except the tires, used an exhaust plug and plastic to cover other parts. It was running 89 octane gas from chevron, just went to get 93 and see if that helps.

Forgot to mention that i have never had it running, bought it with a shot crank. Had it repaired and reinstalled by a certified mechanic. It took about a month between the time it broke to getting it running.

Have not washed anything except the tires, used an exhaust plug and plastic to cover other parts. It was running 89 octane gas from chevron, just went to get 93 and see if that helps.

That low octane might be your problem. Only run premium. I run Sunoco 93.

Seems to have helped, but i cant really try all gears at my house now, road is too curvy and not enough land, i dont want to eat it on pavement :thumbsup:

Any tips on how to test if the hesitation is still there, even if the slightest bit is still there?

(yes i know this sounded kind of dumb)

Bad news: still doing same exact thing, even with higher octane gas. I found the the oil pump idle gear was installed wrong and broke, but that was replaced and installed correctly, still no difference.

It feels like its just missing, but the timing is dead on, im starting to think its the fuel pump?

Could well be.

Would you like me to move this thread to the KX450 forum? I vaugely recall (not my fault if I am wrong) a spate of fuel pump problems and those guys are more on top of the nuances of your bike.

Could well be.

Would you like me to move this thread to the KX450 forum? I vaugely recall (not my fault if I am wrong) a spate of fuel pump problems and those guys are more on top of the nuances of your bike.

That would be fine thanks

Alright guys, had this in the jetting section, but can anyone help me out with this?

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