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Nasty valves theory!!!

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Right, thinking about it, those with, 'nasty valves/valve issues' etc, who has, or hasnt disconnected the breather tube from the airbox (you know the one, from the head), could it be related???? :cry:

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I just dont understand it. How can some people be on the third set and some have not done anything yet?

How many hours between valve sets?

I have about 30 hrs no problem, I must ride like a girl :cry: :cry: :cry:

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do your tits swing up and down? Cuz that's what happens when my girl rides. If so you ride like a girl. The valve issue is due to an engineering issue with the valves or valve train not the air box.

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No I have an A cup. I agree but I hope mine make it until they come up with a solution. Any posts on a cure? I am still searching. What are the MX racers doing a valve job after every race?

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go over to the rmz/kxf forum! those guys are having the same kind of valve problems and are trying some things out. :cry:

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and am on my third set of valves

Got Dust? Yes?

I,ve got 105 hours on my CRF250R with no problems.

Got Dust? No?

See this thread: Dusty conditions/valve recession??

Last I looked it, for those with valve recession it was at:

* Dusty, have valve recession: 10

* Not Dusty, have valve recession: 1

It's not 100% of the problem, but that's a strong correlation :cry:

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Interesting theory!

In my case, the bike is used for supermoto. It spends much of it's time at WOT compared to dirt riding with NO problems.

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motomadman ... sorry, but the dust theory does not explain why Ice flattrackers are having valve issues as well.

All the 4 stroked are having issues. 4 valve design seems to appear sooner than 5 valve(patented by Yamaha) because it is harder to control the mass of the larger intake valves.

It's what we get for good performance.... high revs & fast cams = valve wear

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I agree but I hope mine make it until they come up with a solution.

The solutions a twostroke :cry:

Seriously though the 4 stroke has made things impossible for the privateers... who can afford to rebuild a 4 stroke once a week/every race?

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I agree but I hope mine make it until they come up with a solution.

The solutions a twostroke :cry:

Seriously though the 4 stroke has made things impossible for the privateers... who can afford to rebuild a 4 stroke once a week/every race?

That's the beauty of them you dont have to! Just buy something reliable.

My theory on the valves and other issues is that Honda built the bike too good for the average person with the technology they give you. I think they are just putting a bike out there that is amazing but not realible and obviously don't care, as long as when your riding it you love it. I've ridden this bike and I have to say I think its a great bike. It's as good as my YZ250F but the reliability issues with the valves and the burning oil are keeping me away from it. I think if Honda put out a reliable product it would suck. They've heard about these vavle issues for about 4 years now on their 4-strokes and havent done a damn thing. What are they afraid of?

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the xr's were, excuse me, are reliable. True they're not racing machines but they don't suck either. I think honda as well as all the other manufacturers have to find a happy medium between reliability and performance. They have to start looking into street bike technology in order to get some better ideas for the valves. I personally have a rmz 250 my buddy has a crf250x. As of yesterday my valves are well in spec after 40 hrs. My buddy has had to shim after 30 hours. BTW, which valve seems to be going, or is it anyone of the valves are prone to failure?

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My experience tells me it's slightly random but seems to happen to the faster/aggressive riders. Those that run at wide open throttle and/or on the rev limiter. It's a "time at temperature" thing. Also, the CRF's seem to have a marginal valve spring, I've done 2 engines for a Pro Level rider and he has no issues when the aftermarket valve springs were installed. I've also got experience with a couple bikes that were not raced but ridden all summer/season long with just a standard maintenance schedule with no issues...........

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I definetely rev my bike out pretty well. I don't hit the rev limiter but I get pretty close. Basically I keep the engine under a load all the time. However, yes if you keep bumping the rev limiter you will run into problems much sooner than someone who doesn't. (that is saying everything else is done correctly)

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