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Yz250 running really bad

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i rode my yz250 at a freinds place about 2 weeks ago and it was fine, then i started it the other day and it sounded really bad. its 2006 yz250 not sure what size jets probably stock, vforce 3 reeds, fmf gnarly pipe and shorty muffler, 45:1 belray hr1 and 98 pump gas. also my air screw only moves 2 full turns is this normal?

here a video of my bike and how it sounds. 

 

Edited by c00kiebr0s

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If it was running fine like you said and its running that rich then thats an indicator your left side crank seal could have failed, because when it goes it pushed air and fuel into your flywheel housing and it offsets the pressure required to properly scavenge the head, then it can condense and fuel will pool. You can check and see if you hsve been burning oil which would mean right side crank seal failed. drain the oil and measure how much is there. Also check your reeds

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3 minutes ago, diesel_dean1 said:

If it was running fine like you said and its running that rich then thats an indicator your left side crank seal could have failed, because when it goes it pushed air and fuel into your flywheel housing and it offsets the pressure required to properly scavenge the head, then it can condense and fuel will pool. You can check and see if you hsve been burning oil which would mean right side crank seal failed. drain the oil and measure how much is there. Also check your reeds

Is there another way I can check cause i don't now how much oil I put in it

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Check your reeds for now and if your reeds are bad, replace those, and also run a compression test for the hell of it if the reeds are good

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6 minutes ago, diesel_dean1 said:

Check your reeds for now and if your reeds are bad, replace those, and also run a compression test for the hell of it if the reeds are good

I don't have a compression tester but it feels the same as it always has. Are you sure it couldn't be something easy like adjusting the air screw?

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How does it run after its warmed up? Did it clean up and run like a couple weeks ago?  If still running poorly after its at full operating temperature, start diagnosing carb performance. If it cleans up once warm, look for leaks into the crankcase while sitting. Leaks would come from petcock/float valve or combination there of. Right side crank seal was already mentioned. Diagnosing the petcock/float valve is easier. Disconnect the fuel line to see if the petcock is leaking. Disconnect the fuel line while stored to see if it behaves the same without a fuel source.

Cliff

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If it were me, I would track down why your airscrew only moves 2 turns. I don't have your exact carb, but the airscrew can come all the way out on my other bikes. May be an issue there.

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7 hours ago, Sofiedog said:

If it were me, I would track down why your airscrew only moves 2 turns. I don't have your exact carb, but the airscrew can come all the way out on my other bikes. May be an issue there.

I managed to fixed that, the threads were just full of dirt or somthing so i sprayed so wd40 on there and un screwed it now its fine. 

7 hours ago, Ndrorder said:

How does it run after its warmed up? Did it clean up and run like a couple weeks ago?  If still running poorly after its at full operating temperature, start diagnosing carb performance. If it cleans up once warm, look for leaks into the crankcase while sitting. Leaks would come from petcock/float valve or combination there of. Right side crank seal was already mentioned. Diagnosing the petcock/float valve is easier. Disconnect the fuel line to see if the petcock is leaking. Disconnect the fuel line while stored to see if it behaves the same without a fuel source.

Cliff

Its runs the same when its warmed up and i know the petcock doesnt leak. With the last bit do you mean let the float bowl fill, disconnect fuel and see how it runs? 

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