Crf250x 2004

[benq]

Hi Guy's,

Last year I bought the new 2004 CRF250X, at approximately 1500 KLM'S I put it for a service and the mechanic told me that he found the airbox wasn't air tight as when he washed it, water trickled inside the air box, subserquently this would of let dust in and yes the intake valve had drop considerably. the mechanic went on to say that I would need new valves not to far into the future. Because the mechanic made note of this and also sealed the airbox Honda are doing this under warranty and so they should. My worry is that this might happen again which i will be very disappointed with to say the least. Apparently here in Australia our dust is only 4 microns, which i have been told the bike are designed to deal with 8 microns, so i guess we are behind the 8 ball to start with.

A friend advised me after I get the bike back, I should use the air filter stockings and run a few tanks of av gas through the bike as he believes this will avoid work hardening the valves, yes I have been using valve guard.

I would appreciate any thoughts and ideas on the above and I also realise that CRF250X is a race bike and needs much more attention than my trusty XR400, and it seems worth it when your Riding the little red Roosting Machine.

Thanks in advance
Ben, From OZ

 

[Tony Eeds]

Ben:

Your question is highly technical in nature, so I am going ro move it to a more appropriate forum that you will get better information in.

Come back and tell us about yourself. We have amny members in OZ, hopefully they will pop in and say hi.

 

[Rich Rohrich]

A friend advised me after I get the bike back, I should use the air filter stockings and run a few tanks of av gas through the bike as he believes this will avoid work hardening the valves, yes I have been using valve guard.

Ben - All CRFs both 250s and 450 wear the hard coating off the titanium valves which leads to rapid valve failure. There are lots of theories about why it wears off, (dust being one of them) but none of these theories hold up under real investigation.
The bottom line is the Honda OEM titanium valves wear quickly as do the valve springs. Keeping things clean will help extend their life but it won't cure the problem. Adding lead, avgas or any chemicals to the fuel will do nothing to extend valve life..

On the CRF450s the fix is to change the OEM valves out for a set of high grade one piece stainless steel valves and a high grade valve spring set. This gives the CRF450 the same valve life as the old XRs. The aftermarket companies are still working on a similar solution for the CRF250 R & X models. Until then all you can do is replace the valves and springs on a regular basis with OEM parts unless you want to go a much more expensive route and update the head with bronze valve seats. Going that route isn't cheap and still isn't as reliable as the stainless steel valves and good springs.

 

[cjKTM]

Aren't you concerned of the extra weight of the ss valves and the stiffer springs that they will require? I am hearing that there are very durable Ti valves available although expensive.

 

[Rich Rohrich]

Aren't you concerned of the extra weight of the ss valves and the stiffer springs that they will require? I am hearing that there are very durable Ti valves available although expensive.

Valve springs properly matched to the weight of stainless steel valves have proven to be incredibly reliable. Even a quality titanium valve from Del West or Xceldyne would still have to deal with the low quality OEM valve springs (they cost $3.00 each because that's all they are worth) and the valve seat insert that has proven to be incompatible with a titanium valve. PVD coated titanium valves show a lot of promise, but at $200 per valve it's not much of a solution for most people.

 

[Tony Eeds]

Thanks for the great responses Rich. Also thanks for moving the thread. I was guessing ... :)

 

[Vic]

This gives the CRF450 the same valve life as the old XRs.

WOW! :cool:

 

[mafols]

So...Rich, the SS valves for the 250 aren't a viable solution??? :ugg:

 

[Kevin B]

Hey, that talk about dust being only 4 microns in oz got me thinking. Does anyone know what K@N filters filter down to? Just that they are a popular filter in oz.Wonder if they do the job. Thanks