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FCR39mx hesitant 1/4 throttle

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Finally got a chance to test my bike..

i spend a lot of time in the cruising range and around 1/4 throttle it becomes choppy and hesitant. the rest of the range has lots of power.

 

jetting:

sea level, 3x3,aftermarket pipe with open muffler-

160 main jet
200 main air jet
EMN needle
clip 3
45 pilot jet
No pilot air jet
2 1/2 turns fuel screw
safety wire mod

 

Suggestions?

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Could be slightly rich on the needle , i had the same issue . I went one step down to the leaner EMR ( I think ) .

I'm not 100% sure of the code , someone might confirm . And that someone could be Craigo my M8 .

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went for a ride today and got a chance to ride with out the air box cover. didn't notice a difference until i put the cover back on.

there is noticeably more hesitation in the 1/8 to 1/4 range with the cover on.

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I have same settings. On the 160th main jet there is a lot of fuel, I depressed it to 155, I will depress still, I wait jets.

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went for a ride today and got a chance to ride with out the air box cover. didn't notice a difference until i put the cover back on.

there is noticeably more hesitation in the 1/8 to 1/4 range with the cover on.

 

You have just confirmed a rich condition, this throttle range is controlled by the needle ...

I would go with an OCEMP needle, clip 3....

If it runs better at WOT with side cover removed, install a smaller main j as well.....158 or 155....

Edited by Craigo 485sm
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You have just confirmed a rich condition, this throttle range is controlled by the needle ...

I would go with an OCEMP needle, clip 3....

If it runs better at WOT with side cover removed, install a smaller main j as well.....158 or 155....

thanks Craigo! will swap needles this week and confirm.

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