Power valve - how to clean?

[ozzychris]

Hi there all,

Ive just bought a CRM 250 Mk 2 to cure my mid life crisis - seems very heavy compared to my MX'ers of 25 years ago, maybe I'm just getting old.

I've got the exhasut off for a clean out with caustic soda and thought I'd also clean up the coked up power valve.

I've removed the cables and bolts and the valve is now loose but wont come our thru the exhaust port.

Is there a special way to extract the valve?

Thanks

Chris from Down Under.

[fallenmikethebike]

I don't think it can serviced ,comprehensibly in situ . Others may know of way of removing it from the head,whilst still on the bike.
Unfortunately to get at the real carbonised bits does really require a full dis- assembly.
I'm guessing they weigh about 15 kg more than your average MXr , but look at all the extra bits its carting around , and that frame is pretty robust and built to last .
Regards Mike

[Jonorow]

I have done it but can remember which way it came out, i think it was through the barrel. it was a bit of a squeeze but this is mainly down to a carbon build up and will go back in a lot easier. Jon

[fallenmikethebike]

Hhmm , from memory, i think it has to come out through the access cover above the exhaust port, which cannot be undone with the engine in the frame still, i think .you need to undo both ends of the spindle , noting its relationship to all the other pieces , it must go back in the same way .It's a wise precaution to replace all the orings and gaskets and shaft bearings whilst your in there . Oven cleaner works as a pretty good de carboniser , be careful though that sheite burns your skin .
A heat tolerant grease is a good idea on reassembly to all moving parts.
The upside is once thoroughly cleaned and working again you are rewarded with that silky smooth power delivery again , and good for another 20k .
Regards Mike

[knackeredMk1]

Remove the shaft through from the side and the valve will come out through the exhaust port. It will take a little juggling to get it in the right position but it will come out.

There is only one way it can go back together so replacing is easy.

[fallenmikethebike]

Ah, thanks for that Steve . I had the relative luxury of having mine on the bench ,when i serviced the valve ,so didn't really look to closely at alternative means of taking it apart.
Sorry for any disinformation Chris,i hope she's all back together and running sweetly again shortly.
Regards Mike

[knackeredMk1]

FMtB

I think the system is different on the AR compared to the others.

[fallenmikethebike]

I will have to have a looksee, but from a cursory inspection i think your right, which is maybe why i decided to service all the top end at the same time.