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06 crf 250r not starting after rebuild

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I recently rebuild my crf 250 r i have done this before the full engine crank, main bearings, piston valves etc etc...every thing seemed fined got great spark, last nite i tried to kick it gave it  few pumps of the throtle choke on kick it no.hand on throtle god knowshow many times and nothing apart from.the odd backfired so i decided to bumpstart the bike and it fired rite up idle nicely...no weird noised no knocks...switched it off and tryed to kick and nothing...what do.you guys think it could be? Going.to check the shims 

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Same thing happened to my 07 rebuild it and couldn't get it to start. Re shimmed the valve and started first kick

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@TPA-MX ..i have checked timing and its.ok.and the bike fired up after it been bumped and i will check valves. Thanks

@jonus thats what im.thinking im.going.to measure gaps and see if they out of spec...when the bike fired up it was idling sweet...thanks

Edited by pina11
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I just measured gaps and damn they out of spec apart from left exhaust is dead on .011

rigth exhaust is on .002

 left intake and rigth intake the smaller feeler gauge i can slide in is .0025 

Is this normal after a valve rebuilt?

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Yes because the valves are starting to seat in the will wear a bit at first

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@jonus thanks for the help pulled shims out one buy one and measure how thick they was. Left ex=1.85mm.   Right ex=1.80mm. Left intake=1.70mm. Rigth intake=1.40 

So after i used the a=(b-c)+D this is what i came up with  my feller gauges have inches and mm so i just used the mm measurements

Left exhaust 0.28mm-0.28mm=0+1.85mm=1.85mm

Rigth exhaust .05mm-0.28mm= -0.23mm+1.80mm=1.57mm

Left intake o.06mm-0.13mm= -0.07mm+1.70mm=1.63mm

Rigth intake 0.06mm-0.13mm=-0.07mm+1.40mm=1.33mmDid i do it rite?? So what shim.do i get r ex 1.55 or 1.60?

L intake 1.60 or 1.65?

R intake 1.30 or 1.35?

 

Edited by pina11

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Is this rebuild following an engine failure ?

If so, a spun cam sprocket is a common issue.

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If the engine seized while running and you are re-using the same camshaft,

there's a chance the sprocket has spun and the cam's timing is out versus the rest of the engine despite the dots lining up.

 

(following a rebuild, just like you another TT member here unsuccessfully recently tried to troubleshoot why his CRF wouldn't re-start

fed to the point of selling his bike until the cam timing was suggested and found to be the culprit) so certainly worth a consideration.

Edited by mlatour

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[mention=494592]jonus[/mention] thanks for the help pulled shims out one buy one and measure how thick they was. Left ex=1.85mm.   Right ex=1.80mm. Left intake=1.70mm. Rigth intake=1.40 
So after i used the a=(b-c)+D this is what i came up with  my feller gauges have inches and mm so i just used the mm measurements
Left exhaust 0.28mm-0.28mm=0+1.85mm=1.85mm
Rigth exhaust .05mm-0.28mm= -0.23mm+1.80mm=1.57mm
Left intake o.06mm-0.13mm= -0.07mm+1.70mm=1.63mm
Rigth intake 0.06mm-0.13mm=-0.07mm+1.40mm=1.33mmDid i do it rite?? So what shim.do i get r ex 1.55 or 1.60?
L intake 1.60 or 1.65?
R intake 1.30 or 1.35?
 

Go with the smaller shim for maximum clearance therefore this will give you valves room for wear

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My bike seized in the crank. After my rebuild I couldn't get it to go same as pina11. I had done the valve shims and she has now been running excellent for over 30 hours now

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@jonus thanks man...going to order then now and hope it solves it...ill let u know how i get on....

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@mlatour i check it it was fine....but Got the shims today wassnt expectin the bike to start after 4 easy kick it fired rite up...now i only have to twist throtle once and one or two kick sittin down one foot on the floor and she fires straigh up...and it never been this easy to start even when it was running great i had to prop bike up and stand up and kick it so thanks @jonus how a lil thing can make a diference on a bike lol

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Jst another thing bike seen to smoke a bit when i hit the throtle but i did put a bit.of oil arround the rings when i installed them or could it be tht i over filled the oil on the left side? If i remeber rite i put about 650ml to 700ml hope it clear up when i take it out to break.it in

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Glad you got it all figured out. Just stay on top of your valve clearances, 2006 CRF have a tendency to eat valves quickly

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Pina11 if the smoke keeps up put around a cap full or two of transmission oil into the gas it will soften up the valve rubbers

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I'm glad to see that you have it running I hope it all works out for you pina11

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