dirt bike pops real bad

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1972Challenger

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« on: January 27, 2012, 09:56:36 AM »
i have a 2004 kx250f
i am having a prob with it.. when i go up to el mirage it pops really bad and i can tell there is no real power... does anyone have any sugestions???
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msrn702

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« Reply #1 on: January 27, 2012, 10:52:28 AM »
The valves may need adjusting or jetting.

SLCKREG

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« Reply #2 on: January 27, 2012, 12:50:32 PM »
The valves may need adjusting or jetting.
I thought a kx was a 2 stroke....2 strokes have adjustable valves?? 8)

mobboss

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« Reply #3 on: January 27, 2012, 12:54:35 PM »
its an f model, those are 4 stroke. sounds like it could be any number of things i would start with looking at the plug. 
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1972Challenger

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« Reply #4 on: January 27, 2012, 12:56:46 PM »
brand new plug in it. im also thinking it can be the jets or i need a valve adjustment
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SuperJet

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« Reply #5 on: January 27, 2012, 01:46:36 PM »
Is it running hotter? Sounds like altitude is leaning it out.


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Mine was stiff when working it back and forth on the trailer.
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1972Challenger

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« Reply #6 on: January 27, 2012, 02:01:13 PM »
should be a difference from running it in pomona (where im from) up to el mirage.. i mean, is that altitude change going to affect the bike that much?
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SuperJet

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« Reply #7 on: January 27, 2012, 02:26:57 PM »
should be a difference from running it in pomona (where im from) up to el mirage.. i mean, is that altitude change going to affect the bike that much?
[/quote

I wouldn't think so. Is it popping when you let of the throttle or all the time ?


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Mine was stiff when working it back and forth on the trailer.
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GlassCutter

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« Reply #8 on: January 27, 2012, 02:30:34 PM »
Valves are too tight. 

Shoulda bought a 2 stroke.  8)
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« Reply #9 on: January 27, 2012, 02:39:31 PM »
its the pilot jet dirty if if the bike sat for any time the pilot jet gum up easy fix  i just fixed one and i live in the high desert factory jets work fine up here 

1972Challenger

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« Reply #10 on: January 27, 2012, 02:49:20 PM »
when i let the throttle out it pops.. and it wont idle up in the desert. but when im home it does idle..
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SuperJet

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« Reply #11 on: January 27, 2012, 02:59:12 PM »
Yeah carb would be my guess.the pop off the throttle sound to me like a lean pop. Just check the mixture an like someone else said check your jets if they are dirty they might cause that also


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Mine was stiff when working it back and forth on the trailer.
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berkbryan

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« Reply #12 on: January 27, 2012, 03:04:41 PM »
clean the carb thats what it is

msrn702

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« Reply #13 on: January 27, 2012, 03:22:22 PM »
If its one doing it when there's a elevation change I would think it'd the jetting.

Nixonnow

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« Reply #14 on: January 27, 2012, 05:09:07 PM »
Definately lean pop. Or you have an exhaust leak at the head. It's not going to hurt anything. If you have a fuel screw adjust it to richen it up a bit. Remember how much you turned it so you can put it back to where it was when you get home.
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SuperJet

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« Reply #15 on: January 27, 2012, 05:26:02 PM »
Definately lean pop. Or you have an exhaust leak at the head. It's not going to hurt anything. If you have a fuel screw adjust it to richen it up a bit. Remember how much you turned it so you can put it back to where it was when you get home.


Oh didn't even think of an exhaust leak, yeah if it is a leak it can be fatal. You risk burning down a valve. But I am almost positive it is a fuel mixture issue


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  • Boat #1: 1978 Sanger SuperJet
Mine was stiff when working it back and forth on the trailer.
Once I got it on the water and under power, it was amazing!

 


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