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Extremely frustrated- need help please

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So I adjusted the valve clearence on my friends 06 crf250.

Ive got the timing set right.

cam lobes facing back on tdc.

.005 intake clearence

.011 exhaust clearence.

Good spark plug

After I got it all back together it was hard to start still so id just get a rolling start and pop the clutch. It idled and ran fine but it was getting really hot really fast. Rads are good and its full with coolant.

Tore down the carb last night and cleaned the jets which had visible blockages. Tryed to start it today with no luck. It back fired a few times which had me thinking the timing was off.

I tore into the head once more to check the timing marks and they are spot on. Im really getting fed up with this bike, any help would be appreciated.

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Have not checked the spark, I will have to check asap. The valve clearence was ok on the exhaust side just .002 off. The intake side was .003 on the left and I had Zero clearence on the right valve.

The bike is 100% stock and it has the stock jetting. It got a fresh top end this past fall.

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Your cam looks good as far as being set. I personally don't use the marks and case to line things up. Pull the spark plug and drop a drinking straw into cylinder. Find true TDC and check your cam marks.

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Im having kind of the same problem i just got my bike rebuilt , the guy that rebuilt the bike messed up the timing and the valves so i re adjusted the valves to spec and timings good to , i droped the cam and broke off the decompressor weight but thats not a big deal it runs without it just cant kick it over , so i have to jump it , when it goes it runs like a diesel motor its so noisy , cant be the valves because there are in spec , idles funny and stales if u dont keep on the throttle , im getting really pissed off with the bike , does anyone have any ideas??? Thanks

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Well put it all back together got it started pretty easily. Still running super hot andb idling pretty high. Im stumped

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I have seen a few guys remove the cam chain tensioner, (2 x 8mm bolts) as soon as you remove it it will fully extend (it is spring loaded).  If you just reinstall it when it is FULLY extended.  You will be able to force it back into place by tightening the 2 x 8mm bolts,  but, if you do this, the cam chain will be crazy tight, the bike will be very hard to start. 

 

To fix this issue:  Use a thin screw driver, and release the tension on the cam chain tensioner.  (no need to remove those 2x8mm bolts, leave them tight, just take out the center bolt that covers the small blade screw undeneath that is in the center of the adjuster.  it is spring loaded, you will feel that you are taking the tension off the chain as you loosen that screw.  Once fully loosened, allow that thin screwdriver to spin under tension of the spring.  That will allow it to automatically retension itself (from full loose) now push the kick starter through, if it moves much more freely, that was your issue.

 

A buddy did that exact same thing once, he could only bump start it, very hard to kick over, and it ran hot.  2 minute fix.

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Running hot sounds like the timing could be advanced but its not , are your rads bad?

Rads are good. Didnt have an issue with the running hot until after the reshim. As soon as I start the bike you can feel heat pounding out from the header.

I checked the petcock and it isnt clogged and functioning fine..

As far as the timing chain tensioner goes I did not remove the whole assembly when doing my valve reshim. I used a flat head with vice grips to keep it in place.

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High idle and getting hot means the bike is running lean richen it up by turning out the fuel screw while your at it check and see if the spring the metal washer and rubber o ring are on the fuel screw you need those parts for the bike to run properly 

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Next thing I would check is the hotstart. Clean and lube to make sure its working properly. If its getting stuck open (lean condition) even slightly it will give you the symptoms you're having. That cable runs/routed right where you were working on the head. Moving an pushing it out of the way when re installing valve cover. This could open it and stay open if service was needed.

Edited by iMOTO189

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Well after a frantic early morning working on the bike me and a buddy resolved the issue. Turned out to be the air and fuel screw was out of whack like ericyzf359 suggested.

It ran great all day on the trails this afternoon. Thank you guys for sharing your knowledge and suggestions.

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Im not 100% sure how many turns we ended up with. My buddy starting dialing it in when I was in the house for a few minutes. We put new gas in it as well. I think it had some bad gas in it. Runs like a new bike now.

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