04 yz 250 will not rev all the way out

Garret_yz250
I adjusted all my jetting cleaned the carb check the power valve checked the piston cleaned the air filter new plug. From low rpm I can hold it to the bar and it’s fine but as soon as it gets on the pipe it’s like it’s in a limp mode and just spits and sputters I unplugged the tps and same thing
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Paw Paw 271
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Paw Paw 271 5/14/2018 2:57pm
5/14/2018 2:57pm
Low compression?
Fuel starvation?
Dirty pet cock screen?
Float height too low in carb?
Have you OHM tested the coil?

Paw Paw
Garret_yz250 5/14/2018 3:04pm
5/14/2018 3:04pm
Alright I’ll try these things could this be symptoms of bad reeds? Thank you
mattyhamz2
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mattyhamz2 5/14/2018 3:09pm
5/14/2018 3:09pm
Garret_yz250 wrote:
Alright I’ll try these things could this be symptoms of bad reeds? Thank you
Have you checked them for cracks, chips or if they are sealing properly?
Alec138
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Alec138 5/14/2018 4:44pm
5/14/2018 4:44pm
Could be spark plug (even if it doesnt look bad)
Wet or worn out silencer packing

Friend had his spark plug causing his 125 not to rev out....

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chillrich
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chillrich 5/16/2018 6:26am
5/16/2018 6:26am
Spark plug cap has resistor that should measure 4700 ohms, I've had one open circuit causing this exact problem.
YZed250
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YZed250 5/16/2018 11:49am
5/16/2018 11:49am
Maybe your elbow is hitting your ribs when you give it gas. Regrip the throttle, and should get out of limp mode.
FGR01
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FGR01 5/16/2018 12:06pm
5/16/2018 12:06pm
Power valve may not be opening. This is exactly the symptoms it causes. Could either be stuck with carbon buildup or a problem with the governor mechanism.
TrailDigger 5/16/2018 12:18pm
5/16/2018 12:18pm
FGR01 wrote:
Power valve may not be opening. This is exactly the symptoms it causes. Could either be stuck with carbon buildup or a problem with the governor...
Power valve may not be opening. This is exactly the symptoms it causes. Could either be stuck with carbon buildup or a problem with the governor mechanism.
Seconding this.

If the PV doesn’t open, the bike will ride normal up to the powerband, then it will go flat on it’s face.
Rickyisms
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Rickyisms 5/18/2018 12:02pm
5/18/2018 12:02pm
FGR01 wrote:
Power valve may not be opening. This is exactly the symptoms it causes. Could either be stuck with carbon buildup or a problem with the governor...
Power valve may not be opening. This is exactly the symptoms it causes. Could either be stuck with carbon buildup or a problem with the governor mechanism.
Yup, my KTM 250 EXC stripped a PV gear and wouldn't rev out.

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