[redindirt]

There is a knocking sound when I am kicking my crf250r and there is like one knock when I shut the engine off ..
However it does not seem to be there when it running ..
Is this normal ?

[124]

No. Your decompressor arm is sticking. Take the valve cover off and apply a liberal amount of oil to that area. Check for excessive wear or incorrect operation. If all is good, you could also try applying a small amount of assembly lube to the cam follower (#6).

[redindirt]

Thank you for your answer..

[Vanrock]

are you sure it isn't at the bottom of the kick when the kick starter hits the foot peg? i always thought something was wrong until i noticed the dint in my kick starter

[redindirt]

are you sure it isn't at the bottom of the kick when the kick starter hits the foot peg? i always thought something was wrong until i noticed the dint in my kick starter

He he ,, yes I am sure of that is not the issue..

By the way I pulled the valve cover and had a look at the decompression arm..

It is loose but it is not stuck , I am not sure how it is suppose to work differently then is does now , the knockin sound comes in each turn of the cam when the rocker arm hits the decompression arm and lands on the cam again, but that is just when I turn the engine with the kickstarter , it stops when the engine starts .. You have to excuse my english .

Did the valve check with the valve cover off
I was able to squeeze the .279 mm (.011) under the exhust but it is very tight .. should I re shim the valves ?

[Asmith]

Did the valve check with the valve cover off
I was able to squeeze the .279 mm (.011) under the exhust but it is very tight .. should I re shim the valves ?

The tolerances for valves are +/- .001". If they are tight at .011 and loose at .010 then they are still in spec.

What did you find with the intakes??

[124]

are you sure it isn't at the bottom of the kick when the kick starter hits the foot peg? i always thought something was wrong until i noticed the dint in my kick starter

He he ,, yes I am sure of that is not the issue..

By the way I pulled the valve cover and had a look at the decompression arm..

It is loose but it is not stuck , I am not sure how it is suppose to work differently then is does now , the knockin sound comes in each turn of the cam when the rocker arm hits the decompression arm and lands on the cam again, but that is just when I turn the engine with the kickstarter , it stops when the engine starts .. You have to excuse my english .

Did the valve check with the valve cover off
I was able to squeeze the .279 mm (.011) under the exhust but it is very tight .. should I re shim the valves ?

Make sure your decompressor clearance is at spec first. Apply an excessive amount of lube/oil to that area of the decompressor system.

[Asmith]

Make sure your decompressor clearance is at spec first. Apply an excessive amount of lube/oil to that area of the decompressor system.

The 250R decompressor is fixed. No adjustments. The picture posted is a 450R.

The weight might be stuck and need lube however.

[124]

Make sure your decompressor clearance is at spec first. Apply an excessive amount of lube/oil to that area of the decompressor system.

The 250R decompressor is fixed. No adjustments. The picture posted is a 450R.

The weight might be stuck and need lube however.

OOOPS! Sorry..I was getting this post confused with the other guy with the 450X. Here ya go....

[redindirt]

OK the bike is running

I shimmed the exhaust valves
right valve clearance = .254 (0.010)
left valve clearance = .228 (0.009)

Intake valves where OK

both shimmed to speck.

I covered the Decompression Arm in oil and put it together.

I measured / changed the oil in transmission an it was 600 ml. so nothing is leaking.



Bike was ok to start before but now it starts in first kick. So I am happy with the result og my first valve job.
This is very easy to do and should not take more then 1 hour next time around.

Thank you all that replied.

[fbr]

I am going to venture a guess that redindirt was describing a perfectly normal sound... the roller on the exhaust valve fork snaps when the decompressor cam rotates under the roller during kickstart. With at least idle rpm the decompressor stows and the noise goes away. On a related note, that decompressor counterweight is susceptible to damage during maintenance and servicing. I had one break off and get into the flywheel and derail the cam chain. I am just guessing that I might have inadvertantly put some stress on the counterweight at some time. The manual recommends replacement periodically.

[redindirt]

Yes well like I said I don't see how it would work in other way...


I have seen many topics regarding starting problems on Honda CRF 250 .. Checking the spark plug is something worth considering.. Mine was not pretty .. covered in carbon an gas .. cleaned it up and bike started better cold .. It getting cold in Iceland now..