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2001 YZ 250 Won't Hit Powerband

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What is up beauties!

 

I'm having an issue with my recently traded for yz 250. When i traded for it, i was aware of the problem. It has strong bottom end but as soon as it tries to go mid-top end it just.. doesn't. Sounds kind of like a sorta deep bwahhhhhhhhhhhhhhh, with a constant pitch, not hitting the band. You can feel the lack of power. So here is a list of what i have done to it so far. I haven't tested it yet, but let me know of any other suggestions.

 

-Cleaned carb, was a little dirty. 

-Found out the main jet was a 175 instead of what should be a 172, going to buy a 172 tomorrow.

-Cleaned powervalve out. It was pretty sticky in there, but i'm not sure if it was sticky enough to stop it from opening.

-Ordered a new silencer, pro circuit r304 shorty. 

-Took a look at the FMF fatty already on the bike. It has a slight bend to it, but nothing extreme enough to effect performance THIS bad. I made sure to clean it out as well.

-Cleaned air filter/box

-Checked compression, was in a good range.

-Changed Plug

-Put new gas in, new fuel line on.

-Adjusted Clutch cable

-Checked piston for scores, it was pretty damn clean.

 

As far as i can remember, that is all i have done. I couldn't think of much else to check out. I guess reeds would be a good idea, but it doesn't seem like that kind of issue. Let me know if you guys have any more suggestions for me! thanks

 

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What is up beauties!

 

I'm having an issue with my recently traded for yz 250. When i traded for it, i was aware of the problem. It has strong bottom end but as soon as it tries to go mid-top end it just.. doesn't. Sounds kind of like a sorta deep bwahhhhhhhhhhhhhhh, with a constant pitch, not hitting the band. You can feel the lack of power. So here is a list of what i have done to it so far. I haven't tested it yet, but let me know of any other suggestions.

 

-Cleaned carb, was a little dirty. 

-Found out the main jet was a 175 instead of what should be a 172, going to buy a 172 tomorrow.

-Cleaned powervalve out. It was pretty sticky in there, but i'm not sure if it was sticky enough to stop it from opening.

-Ordered a new silencer, pro circuit r304 shorty. 

-Took a look at the FMF fatty already on the bike. It has a slight bend to it, but nothing extreme enough to effect performanceicon1.png THIS bad. I made sure to clean it out as well.

-Cleaned air filter/box

-Checked compression, was in a good range.

-Changed Plug

-Put new gas in, new fuelicon1.png line on.

-Adjusted Clutch cable

-Checked piston for scores, it was pretty damn clean.

 

As far as i can remember, that is all i have done. I couldn't think of much else to check out. I guess reeds would be a good idea, but it doesn't seem like that kind of issue. Let me know if you guys have any more suggestions for me! thanks

 

This may be a lean condition now that i think about it,,,, Let me know

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leave the PV cover off, ride the bike, and see if it is actually opening when you rev the bike. 

 

Doesn't sound lean to me. If anything I would think that it is too rich.

Edited by BDubb106
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I said the same thing in your other thread. Leave the PV cover off, ride the bike, and see if it is even opening.

 

Your bike is showing signs of a rich condition, not a lean condition.

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Got an 02 yz250 I traded for with the same problem. I did everthing you did except my jets were stock. In addition I checked the timing which had been retarded so i returned this to stock per the method in the owners manual. I also visibly verified the full function of the powervalve. The timing adjustment helped but the "hit" still just isnt there. Going to check the TPS in the next couple days and see where its set. I remember a KX250 I had having a stronger pull in the mid upper than this one has. I've had a yz450f for the last year, maybe its just numbed me a bit to the pull of the 250. If i make any progress with the TPS check I'll let you know.

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Borrow a different pipe and try that.  You sure you cleaned it out properly?

 

Also work out if the problem is a function of RPMs or throttle position or both.

 

There are some older threads asking the same question.

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It needs fuel to rip. Is it flat on top or does it sputter? If carb has vacuum slide the diaphragm may be bad.

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