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2006 crf 250r

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Doing a complete rebuild on. My 06 250 everything is good just the stock crank end bearing seized no damage to motor at all valves look to be OK and re used I'm curious on what to go with for bottom end OEM ? Wiseco ?;hot rods what have any of u guys run and how did u find the life of them

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Stay away from wiseco cranks. Oem, pro x, hot rods all good. Make sure you do the main bearings, id be suprised if the stock valves on a 2006 were still "good".

Edited by nzgsr

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This will be my first time doing bottom end I did the top end on my 2 stroker last year used a wiseco piston there pistons seem to be good I was just curious about the cranks thanks for the tip

The valves seem to have a bit of build up but don't seem to be bent just prob need a cleaning there's no chips near the seats. Another question with the can chain if it doesn't look worn should it be replaced any way ?

Edited by ktm_125sx

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Definately replace the cam chain and tensioner. Dont try and clean the intake valves, as they have a titanium coating strips off easy. As long as the valves seal (check by filling the port up with gas) and you have the recommended clearance then your all good. But early crfs had big valve/seat issues with the valves recessing into the head, as soon as they start to move and require shimming, its about time for a valve job. Welcome to the world or 4 strokes. $$$$

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I will install them and check for that I bought the bike as is and looks like they've been done considering the looks of them I whent for a 250 4 stroke for more power and to get out of mixing gas doing a valve job do I need to replace the seats even if there not damaged or just clean the hell out of them and install new valves

Edited by ktm_125sx

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If installing new valves the seats need to be cut at a machine shop, if there damaged or have been cut too many times you then get new seats installed, or get a new head. You have to use a shop that specializes in this and ideally a 5 angle seat cut, ur local machine shop may not have the tooling/equipment to do this.

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OK the bike is completely stock don't think it has ever had work done the shims look to still be big and there is no play in the guides should I just re install my valves and just clean the bottom of the head and valves ? And check clearence

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Do yourself a favor and replace the cam chain, tensioner and at least the valve seals while you're in there...

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Yup getting stock chain stock springs and tenssoner and seals are comeing with my kit just have to double chck my valves dont leak but everytging looks really good thanks for the tip

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The cam chain wear is determined by how much it has stretched. The honda service manual specifies the maximum stretch allowed before the cam chain needs to be replaced. Will pull the manual and look up the specs if you would like to know..

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Replace the stock cam chain tensioner for an aftermarket manual one, the auto ones are known for randomly failing.

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Im also trying to find out but my manuals dont telll me the measurement that my forks sit above my clamps anyone no ??

I'll go to my bookshelf and look that up for you... Be back in a minute :-)

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Thank you !!! I was surprised my books didnt have this info!! So the forks barely pop out the top!! And manual tensioners i havent really looked yet i ordering oem intake and exh springs cam chain and a couple other small parts today i figured a oem cam chain would be better than aftermarket the only aftermarket one ive foubd was wiseco dont no how good they would be

Edited by ktm_125sx
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