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What is surging ?

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My English is not perfect , trying to solve a condition similar to gas starvation at low  throttle , surging is  a lean condition from what i read here , in my case it gets worse when temperature is hotter . Thanks  

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6 minutes ago, ohiodrz400sm said:

Surging is when the engine speed fluctuates and increases while at steady throttle and load.

Sent from my XT1650 using ThumperTalk mobile app
 

So similar to gas starvation , could it be a fouled spark plug ? 

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Small throttle opening surge is usually a lean mixture.  Simple answer richer idle mixture, but this doesn't always work.

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2 hours ago, 38super said:

Small throttle opening surge is usually a lean mixture.  Simple answer richer idle mixture, but this doesn't always work.

Ok thanks 

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Unless your carb is gummed up or there is something else wrong, the 3x3 mod and JD jetting kit will take care your lean jetting issues. 

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31 minutes ago, brucen said:

Unless your carb is gummed up or there is something else wrong, the 3x3 mod and JD jetting kit will take care your lean jetting issues. 

i have fcr mx with jd kit and 3x3 , will try raising needle  , thanks .

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do not move the needle. for problems at low and very low throttle position you must check: needle diameter , pilot air jet size, pilot jet size, fuel screw

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2 hours ago, 30x26 said:

do not move the needle. for problems at low and very low throttle position you must check: needle diameter , pilot air jet size, pilot jet size, fuel screw

Thanks for helping me fix a hanging idle earlier this year , it was a too rich condition , just like you said ,a too lean or rich mixture will drop idle , first reaction would be to try to raise idle with idle knob , this will open slide too much . My surging problem was 80% gone today ( colder temp ) + i cleaned air filter , did not change anything yet , like i said in first post , it gets better with colder air ( leaner) , i only tried fuel screw in and out but no change .  Sea level , 45 pilot , no paj ( do not  like it ) jd red needle 4 clip ,  20 celcius , at 20 c surging  is  acceptable , very bad over 25 , it s no big deal because temp will soon start dropping here and i will change to blue needle , thanks 

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22 hours ago, habs said:

 My surging problem was 80% gone today ( colder temp ) + i cleaned air filter , did not change anything yet , like i said in first post , it gets better with colder air ( leaner) , i only tried fuel screw in and out but no change .   it s no big deal because temp will soon start dropping here and i will change to blue needle

better when cold and no effect from the screw usually means that  you are still rich =  you will never need the blue richer needle, even in noticeably colder climate.

try to find the correct jetting using 42 pilot, for the winter you will not need to change it too much:  less than 0.5 turns at the screw, 1 clip at the needle and 2.5 points at the main jet    

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33 minutes ago, 30x26 said:

better when cold and no effect from the screw usually means that  you are still rich =  you will never need the blue richer needle, even in noticeably colder climate.

try to find the correct jetting using 42 pilot, for the winter you will not need to change it too much:  less than 0.5 turns at the screw, 1 clip at the needle and 2.5 points at the main jet    

Fantastic , I'll try this , thanks again 

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