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wondering on causes of valve issues...

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I have a few questions for all of the people that have valves failing. How often have you been changing your oil? What brand and weights of oil are you using? How often do you change your oil filters? How many of you are riding 2005 vs. 2004 models? I was wondering if their is some sort of common link between all these valves breaking.

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So nobody is posting what all happened before they broke their valves. Why not? I think that if it's such a big issue, then maybe we all need to put some real ideas on here instead of just complaining.

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Heres what I can tell you we have a 04RMZ I just replaced both X-valves but this wasn't at all the bikes fault, The conditions that led to the fauile...

1. The muffler bolt came out and I couldn't pull my son off the track in time and he wound up cracking the header pipe right at the bend, there was a crack on top that we tig'd but I didnt see the crack on the bottom..ie sucked cold air I think and burned the valve right in front of the exhaust I replaced both to be sure, didnt have the x-tra cash to do the intakes.

2. I think is the Problem with the failing valves is the heat generated to the valve springs, our springs have already lost half the spec. in 20 hrs. I contribute some of this to the fact that my son didn't turn the rad cap all the over, in practice one day and he started to over heat, but still with how hot these bikes run I think it's weaking the valve springs.

3. My plan to try and correct this is to pull the head every 15-20 hrs. and look at the valves and replace if any inperfection exist, and make sure to replace the springs. Checking into dual springs but they haven't been proven on this bike yet so @ 180.00 a set compared to 32.00 stock I'll just replace with the stockers. Pulling the head isn't as bad as I thought it would. This is our first 4-stroke always had 2-strokes but I did the head in about 7hrs the first time, but know that I have a clue on how it to do it I should be able to cut this down to about 4 hrs I think.

4. As everyone keeps point out maitence is the key to keeping your bike working properly. I can't speak for all but we race this bike so expect if I don't pull the proper maintence it will fail, and then it's not the motorcycle thats at fauilure its the owner/mechanic..Don't blame the bike for something you could have caught and fixed. Valves and springs are a lot cheaper than dropping one and taking out the whole engine. Maintenance...Maintenance...Maintenance

And thats all I got to say about that.

Hope everyone else can contribute the facts not the hype.

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issac I forgot we change oil after every ride 10-40 valvoline oil filter every other oil change, small price to pay to keep everything working properly....

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2004 KX250f, ridden in 125c and youth class by 115 lb. rider usually finishing in the top 6 out of 20 riders.

Since the wear is on the face of the valve I doubt the oil question is relevant. No oil is ever in that area. We use Amsoil 100% synthetic motorcycle oil.If the valve clearance was getting bigger then maybe some part that gets oiled could be wearing. That is not the case. The valve face wears where it contacts the valve seat and the clearance goes away. Once the hard coating is gone off the valve face, shimming is useless. I am leaning more toward the cause of the problem being very fine dust making it past the filter when the bike is ridden in very dry dusty conditions. The people I know locally who have had no or few problems usually only ride on prepped mx tracks. Ours has had proper air filter and oil change maintenance but was sometimes ridden on our 1 mile practice track in very powdery conditions. The left intake has been replaced twice under warranty and the right intake replaced once. I rebuilt the top end and replaced both valves again along with the springs prior to starting the Alabama Fall MX series. The original springs still were within .020" in length to the new ones. I found evidence of dust in the top of the carb during the rebuild. All the intake tract was inspected and no source of the dust could be located except that it is making it past the filter. Stock Kaw filters are used, well saturated with Bell Ray filter oil worked into the foam. The bike is no longer ridden on our track when it is dry and dusty.

I also rerouted the cooling flow thru the head adding a outlet where the factory casting plug was between the left intake and exhaust valve. The coolant now flows from that outlet to the left radiator. The factory outlet on the right side of the head still goes to the right radiator. I dummied the whole assy together on the work bench and flow tested it with a garden hose to find the proper restriction to place in the factory outlet (right side) to equalize the flow thru both radiators. The outlet from the top of the right radiator (which connected it to the left radiator) is plugged. A vent screw must be installed in the top of the right radiator tank to allow air to escape when filling the system with coolant. Both radiators seem to warm up equally from a cold start, bike has not puked any coolant with the stock cap even though it is filled to the top. Time will tell. :cry:

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I know there has been some pics posted on the re-routing issue..but do u have any pics? Thanks

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Thanks for the great input. I think the more we look at stuff like this, the causes might show up. Just some questions:

suz459: is your header pipe stock? I think FMF was looking at the sealing as a possible air leak and burning the valves when they made their head pipe. Has anyone seen that thing yet? It has about 4 2-stroke pipe springs holding the pipe to the flange plus the flange.

4strokesrule: I don't know if I agree with the dust causing the problem. Where I practice it is usually very dusty b/c we have a lot more quads then bikes, however I have been using a clean filter every ride. And I've not (fingers crossed) seen anything (knocked on wood) yet. So I'm just tring to figure out if I'm sitting on a time bomb, or if maint. will keep this away.

I haven't been changing my oil as often as every ride, but I keep it at about every 3 rides and the filter at approx. every 10 hours. So far no problems. Are these valve issues happening on one coast more then the other? What is the normal riding temperature when you see the valves go? I don't know what else we need to look at as far as facts go.

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Another couple of questions: what time of year did it happen and do you ride the clutch hard coming out of corners? I didn't hear of these problems until early this summer and someone explained to me that slipping the clutch can produce an enormous amount of heat in the engine.

I don't think the lemon theory applies. People that are having this problem are having it repeatably.

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'04 RMZ... 9 months for first intake valve to go bad. The replaced valve only lasted two months.

I'm a 150lb. Intermediate cross country/hare scramble/trail rider, and I ride the occassional MX practice.

I clean my No Toil airfilter every ride. Change my oil every ride... two rides max. I've used mostly Mobil 1 MX4T... occasionally Mobil 1 15-50 red cap. I change the oil filter about every 4 or 5 oil changes. For the first 9 months or so I ran 91 octane Shell pump gas, after that I've been running VP-Red (105 leaded).

Also, contrary to what everyone thinks might be causing the problem, I never rev my motor. I ride it like a 450. The only time I've ever hit the rev limiter, was when I did it on purpose after installing the stainless steel valves just to see how they reacted at high rpms. I'm very easy on my equipment, so I don't know what the issue is.

One thing... since I did my big tear-down (wmr head, stainless valves, conical springs, split cases) and cleaned the oil filter screens inside the motor, my bike has run W A Y cooler. I don't know exactly which part of that whole change is responsible, but its very noticeable. I suspect that it's cleaning the clogged oil filter screens in the motor.

~Tex

'04 RMZ

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We live in north central Alabama right off interstate 20. The first failure occured in about 2 months. The bike was purchased around April. Kaw replaced the head and valves. The left intake valve was the one that was bad. In about a month the left valve went 0 clearance again. It was replaced by Kaw. When I tore it down during summer break both valves were worn about the same. I replaced both intakes and the springs with stock units. I don't think my son rides the clutch alot. I have never noticed it happening at the track and I watch him pretty close during races. The stock clutch is still in there.

I don't have any pictures of the re-routed cooling system but it is different than any posted on here. The hardest part of the modification is getting the coolant piped thru the valve cover while maintaining an oil seal. I used JB weld to level the top of the valve cover, came thru the cover with a 3/8 pipe nipple which was just long enough to install a 90 degree elbow. An "o" ring fitted around the pipe nipple is compressed when the elbow is screwed on sealing the pipe to the valve cover. The elbow has a grooved washer JB Welded to it to insure the "o" ring stays in place. Use an adapter in the elbow to attach 1/2" coolant hose and route to the top of the left radiator. The rest is as explained in the earlier post.

Take the plate off the top of your carb and look for evidence of dust. It is only attached by 2 allen screws. I had never seen evidence of dust in the intake tract till i looked there.

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Do you mean 0 clearence in the the valves were too tight? What did Kawasaki have to say when they paid for the new head? I didn't think there was any warranty on them at all except for recalls. If Kawasaki is going to warranty stuff, then what do we have to worry about? And if there is 0 clearence then I can see why the valves would be wearing faster then normal.

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Another thought: what are the last 6 numbers of everyone's VIN's that have had valve problems? If there is a certain run of bad bikes that maybe slipped through QC at the Kawi factory, it could be the cause.

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Good question... how long do our warrenty's go? 3 months? Mine is def. over.... :cry:

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Whenever I got my bike they told me both verbally and in writing that the bike had no warranty at all. I don't see why a dealer would give away a head that was completely set up. That's pretty expensive when you think about how much they made off the bike. That may have been half the profit. Could we have more info on that warranty or exchange deal please?

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There is no warranty but.... if your dealer goes to bat for you and calls their service rep they may ok the warranty work, especially if it is an obvious defect with the machine.

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There is no warranty on a Mx race bike. However if you have a great dealer and especially if you "Carry the colors" ie. race and help promote them, they can be especially helpful when something which should not happen does. This is why you should not let low price "out the door" be your only consideration when purchasing a bike or any similar product. I bought a new 85 Kaw a couple years back and a bearing burst in the governor for the power valve taking out the clutch basket gear, and 4 tranny gears. Our dealer (who also is a Mx racer) got Kaw to cover all the parts.

Kaw replaced the whole head so they could get the original 1 back to analyze it to help find out what was causing these failures. Special thanks to Jason and Mike at Talladega Cycle Sales, Talladega Al for all their support and assistance! :cry:

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It mostly depends on your dealer, I can't remember an issue that kawi hasn't covered Shelled trans bearing and cases, cracked piston,broken valve and head,a new cyl on my kx250 and multible other problems with my other bikes, I deal with rainbow cycle in rogers Ark. never once has this co. failed to impress me, even if they couldn't help they still give it 100%, I live 2 hours from them in springfield Mo. and I still wouldn't buy local, our dealers just don't put out the effort.

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Hey Issac

Sorry it took so long been busy, the header is all stock like I said the Exhaust valves were totaly our fault, I do think the valve spring are a big issue, the more I think about dual springs are the way to go should resolve most of the float issues and should be kinder on the seats, and their about the same price as WMR conical springs.

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