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2013 yz250 sputter at 1/4 to mid throttle

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I'm currently running:

 

Pilot jet: 50

Main jet: 180

Needle: n3ew - 2nd clip

Air screw: 1.5 turns out

Spark plug: br8eg, plug is wet black at threads but brown at tip

 

Fmf gold series exhaust and silencer, rest is stock.

 

93 octane pump gas mixed 30:1 with yamalube 2r oil

 

Riding strictly mx tracks at 307m (1007 ft), so bike is revved most of the time.

 

Bike sputters/hesitates right before getting into the powerband, check out this video at around 3:45...last weekend temp was around 18 deg. Celcius (65 f),

But seems to do it at warmer temps too.

 

 

I'm new to 2 strokes, is this normal? Any suggestions?

 

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have you tried a different plug ?


No, just the stock br8eg so far

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When you say 2nd position are you talking about from top or from bottom? From bottom it will introduce more fuel earlier on in the throttle range making it kinda cough up from the beginning of the 1/4 to 1/2 range and smoothen out as it starts getting more air to help out. but at 1000 feet i have seen that is okay but try ans put the needle in the middle or 3rd posi. And by any chance have you changed the needle from stock that has a different taper? If so that can cause a difference

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When you say 2nd position are you talking about from top or from bottom? From bottom it will introduce more fuel earlier on in the throttle range making it kinda cough up from the beginning of the 1/4 to 1/2 range and smoothen out as it starts getting more air to help out. but at 1000 feet i have seen that is okay but try ans put the needle in the middle or 3rd posi. And by any chance have you changed the needle from stock that has a different taper? If so that can cause a difference


I believe its the stock needle and its at the 2nd clip from the top.

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I believe its the stock needle and its at the 2nd clip from the top.

Try putting it in the middle then see if it helps

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Try putting it in the middle then see if it helps


So this would richen the mixture right? Is that sputter before the powerband from being rich or lean at that throttle range?

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Yes, what it sounds like to me is the more you open your throttle the more time it takes for it to get the correct fuel mixture in causing said bog

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Yes, what it sounds like to me is the more you open your throttle the more time it takes for it to get the correct fuel mixture in causing said bog


Ok I'll try that and see if it helps, thanks!

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Raising the needle works great, especially if you reduce the power jet to a number 40

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to the OP ,

 

you will always be chasing your tail with the standard needle 

suzuki needles work great

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to the OP ,
 
you will always be chasing your tail with the standard needle 
suzuki needles work great

Do you own a YZ 250?

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Just now, Kinger317 said:


Do you own a YZ 250?

no

 

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