The valve fix... I hope

[dirtmachine]

hey i don't have a problem with you getting rid of the bike. just don't go around saying that the bike is full of problems if you've never had any.

[mike_perry]

Regarding the spring pressure/valve face recession issue, and the decreased amount of effective running time after a valve replacement:

Most folks only change the valves when they have a valve face recession problem- there is a good chance the springs are toast too- and if they are, you stand a good chance of only getting 50% of the service life out of the 2nd set of valves. Valve bounce on the seat will kill any valve face, stainless, titanium, inconel etc.

Hard coating:

The OEMs are using a DLC (diamond like coating) that is deposited onto the titanium in a vacum,and creates a shell around the metal. Titanium is soft, and this is the OEM's way of trying to defeat its natural tendancy to deform under impact. However, no matter what you do to the surface, the titanium is still soft and will deform, causing the coating to fail. It is nothing like the carburizing done to steel. That is a process that actually reacts with the material to surface harden it to a specific depth depending on the application.

Soft seats-

The bronze seat material we use for seats contains 5% nickel, so it isn't as soft or as suseptable to chemical wear as the bronzes being used in the 70's. This material is designed specifically for for use with titanium valves, and while soft enough to give some cushion, it's not so soft that it just deforms like mad. We have several shops installing our bronze seats in heads to extend the life of the titanium valves.

The problem with extending the face life of a titanium valve is that titanium has a finite fatigue life. It breaks. If you quadruple the time that the valve face lasts, the stem may come apart. At that point you have what's known as an "energetic disassembly".

As far as the power vs spring pressure issue- The amount of increased spring force required to control a steel vs titanium valve in a well designed combination is not great enough to create a problem. In most cases you couldn't tell the difference.

Now think about this- even if you had a measureable loss- say one full horsepower at peak power, compare that to how much power you lose as the valves go away, and you begin to lose cylinder pressure in the middle of your race. The valve face recession will create a greater power loss than a well designed stainless conversion.

Now at some point as the ignition boxes are changed, and power output increases, and sustained RPM for a given model moves up, it may be that the only way Rickey C. is going to get the last 1000 RPM out of his 14,000 RPM machine is with titanium valves. 98% of the riders and bikes out there aren't going to be riding at that level, and they'll opt for something that will give them longevity at 13,000 RPM. Or, switch to a bronze seat and run the titanium valve.

Hope this answers some of your questions-

Mike Perry

KPMI

[MTRACING]

Bob at WMR has put a great amount of time into testing, and lucky for us he has taken all the ? work out of the problem and came up with a great fix. we use wmr cams there je 13:1 piston, and we are waiting on there new spring kit with a set of there one piece Ti valves. Bob thamks again for all you hard work on all your 4 stroke development. WMR, the way to go

[Jim_bo]

Bob at WMR has put a great amount of time into testing, and lucky for us he has taken all the ? work out of the problem and came up with a great fix. we use wmr cams there je 13:1 piston, and we are waiting on there new spring kit with a set of there one piece Ti valves. Bob thamks again for all you hard work on all your 4 stroke development. WMR, the way to go

I'm sorry, but we are not all racers. I bought my KXF for my son to ride recreationally. The $800+ WMR fix is just not an option. I would gladly sacrifice a bit of power for reliability and longeveity. I hope the new springs and stainless valve solution will do that.

Jimbo

[dirtmachine]

jimbo has it covered, for us rec riders out there, that money is just too much. Not to mention all the 13,14,15 etc. year olds out there riding these things. their pockets are even less deep.

[Aaron_Silidker]

My opinion....and it will make alot of people mad, if you have a high performance MX machine and can afford to buy one, you should be able to afford 800 dollars worth of engine parts. At my last yearly count when I rode a kx125 and had to run race gas...replace the crankshaft every year, rebuild suspension, top ends, etc, I was at nearly 2000 dollars for a season of riding and I do not race, only ride a few times a week recreationaly.

IMO, the 13,14,15 year olds riding these didnt buy them for themselves, and if they did have that much cash, they can also afford the engine fix. Motocross is one hell of an inherently expensive sport and I chalk the valves and springs up to just another one of those motocross expenses.

[Suz459]

I just called Ferrea to find out about there valves and to get a price on the internet the only valve offered for RMZ/KXF was the the Titatnium they have not started to produce these yet they are waiting on materials, the SS Valves everyone keeps talking about must be a custom order. As far as pricing go's the Tech I talked to said that pricing for the RMZ/KXF was not avaiable yet but should be the price range of the CRF450 which is aroung 80/ea. they will also offer a 1mm oversize valve. I'm new to this 4-Stroke Stuff but the price didn't seem to extreme to me. At this point they don't offer a spring kit, but they do for the Honda so maybe in the near future they'll have one.

[dirtmachine]

80 bucks a valve is reasonable. However, not almost 200 bucks as WMR asks for. same with springs, stockers are 8 bucks and wmr is asking 50 for theirs. Now is that spring 6 times better than the stocker? Is the material 6 times more expensive? i think not.

[WMR]

(quote)

I'm sorry, but we are not all racers. I bought my KXF for my son to ride recreationally. The $800+ WMR fix is just not an option. I would gladly sacrifice a bit of power for reliability and longeveity. I hope the new springs and stainless valve solution will do that.

We couldn't agree with you more Jimbo, Thats the main reason WMR has been working so hard on our Stainless Steel valves and new Conical valve springs. Our goal is to run a Stainless Steel valve while keeping the performance of Titanium. With our new Conical springs that has become a reality, we are able to keep the effective valve mass to within 1 gram of stock. Stainless valves are easier to make, therefore less expensive but without the right springs they would have developed their own set of problems. Finding the correct spring has been the reason it is taking so long for aftermarket companies to release stainless valves. We have finally released our Stainless Steel valves and New Conical springs, check out the Tech Tips section of our web site to learn more at www.wmr1.com

All of our early testing with the stainless valves and Conical Springs has been in heads with bronze seats, however We are in the early stages of testing only the Conical springs in a brand new 2005 RMZ250 and Honda CRF250 stock head with, stock seats, stock valves, and stock retainers. We need some time on the motors before we will know for sure, but by eliminating valve spring surge and valve float from the equation and lowereing operating temps, all indications are that the stock vale train life of all four stroke motocross bikes will be extended. So don't give up yet,the goal is to keep opperating costs down while improving performance and longevity. ?

Jimbo

[Aaron_Silidker]

Spoke with Ferrea today, they will custom make the stainless valve for the price quoted in the first post but do not have a titanium valve available because of the tiny stem size...they wont for 4-6 months, price will be 80 each the guy claimed. They also do not recommend running the stainless valves with stock springs and keepers because of the weight issue, but that is where the WMR spring comes in play for me ? .

Wish I was home and not at school so I could get these parts and beat the crap out of my bike to test them.

[Jim_bo]

WMR,

I'll have to read your website to learn more about your conical springs, but I am concerned that if you are shaving weight off of the spring, you will be compromising spring life. From everything I have read and researched, I think the spring has more to do with the problem than the valve material. Valve float allows the valve to slam shut causing the cupping. Therefore, I am not fond of the idea of compromising on the spring. I would much rather allow a bit of power to be robbed from the engine to push valve springs than to replace valves. After all, the yamahas have almost NO valve issues, and they run 5 titanium valves.

Any comments??

Jimbo

[TexLaBo]

I had to special order my SS valves from Ferrea. They were still $34 a valve. It took them 8 days to arrive at my door. Well worth the wait and the money in my opinion (...no offense to the WMR guys).

It only makes sense that a company that does nothing but make valves will be cheaper than a company like WMR that only sells a limited number of valves. Ferrea doesn't have a part number for them at this point. They have the specs and the blanks, and if you can wait 7 - 10 days, they can make you a set.

UPS will be dropping off my WMR stuff tomorrow, and believe me... I'll let you guys know how it all works as soon as I get home from the first ride on Saturday. ?

~Tex

RMZ+ssv

[Aaron_Silidker]

Jim-bo, the weight of the spring has nothing to do with the valve floating. From what I understand and from what seems to be the general concensus, the springs vibrate so badly that they have no control over themselves and cylinder pressure as well as the piston closes the valve at high rpms. The WMR spring supposedly eliminates this resonant frequency through some clever engineering. The technology is borrowed from F1 cars and comp cams uses it in their new top of the line springs for cars.

[CanadianKawi]

I'm definetly not trying to complain here, but some guy's are saying $800 isn't bad for these high performance machines. The problem is you shell out X amount of dollars for the bike, and then have to rebuild the engine in order to ride the thing ? I think something is wrong here, no? I haven't had any trouble at all with my bike (25 hours on it) but I am also starting to think that it is only a matter of time before I replace my valves as well. Now if the $800 fix would be the end all then I would do it with no further complaints, but will these new valves,springs,seats and whatever be the cure??

[WMR]

One of the best things about the WMR Conical spring is that it does not compromise the integrity of the spring, the new springs design eliminates the extra spring mass needed in a conventional spring, to combat against spring surge. We are actualy providing 2 additional pounds of spring pressure from stock specs, but doing it with a spring that weighs 32% less. A conventional spring needs to have heavier wire and closer coils to even come close to the Conical springs performance, and a conventional spring can never eliminate harmfull spring surge (harmonics). Because of the Conical springs unique design the entire spring performs more efficiently. This lowers opperating stresses and allows the motor to perform closer to its full potential.

[dirtmachine]

I got nothing against you WMR but most people who buy a dirtbike aren't looking to get all these little power gains. Now while what you're saying may very well be true, is there any actual proof of this? Once again, i must bring up the fact that if the engine is revved so high, you will create problems. There is a reason why car manufacturers tell you not to redline their engines, to avoid problems such as these. If people rode the bike like they're supposed to ride a 4 stroke there would surely be many less problems.

[mike_perry]

Valves continued-

No need for anyone to get huffy, or to make assumptions about what another should be able to afford. The thing is 4 strokes are coming into the dirt bike scene full time, no way around it. We in the aftermarket are coming up with solutions that will help round out the applications to make the bikes palatable for all budjets.

Our conversion kit for the CRF450 has proven to be a very successful option for riders that want to convert to stainless. Folks that want to run ti valves and handle the issues that arise when using that material will do just that.

No judgement on what's better, just what fits the individual's needs.

The 250s have more than one valve train issue, and when we release our kit it will address all of them. We are just finishing testing with a tappet that is designed differently than the OEM and will offer increased strength in critical areas. The dual spring kit we will offer will be designed to work with stainless valves on the stock seat material with a stock ignition box, and, for an all out race bike with a modified ignition box, an aftermarket cam, and titanium valves.

I honestly believe that bronze seats should be put into any head running titanium valves, and that the rider should keep track of time on the engine and replace the valves at regular intervals so he doesn't have a catastrophic failure.

As for installing steel valves with the stock springs, I would recommend against it. The springs on these heads are barely able to control the light titanium valve. If you increase the reciprocating mass without compensating for it you are going to have problems.

That is why we have chosen not to sell stainless valves for these heads yet. We certainly have the material to make them, but it would be brutal to just take some guy's $35.00 per valve and send him on his way knowing the chances are great that he'll have a failure of some type. We won't be releasing valves until we are completely comfortable that the entire system will work together. At that point the kit components will be available from our regular distribution network, and hopefully folks will find the pricing reasonable, as they do with the 450 kit, when weighed against the maintainence cost of frequently replacing the ti stuff.

Mike Perry

Kibblewhite Precision Machining Inc.

[Jim_bo]

Well, I do appreciate that Kibblewhite and WMR are here reading these forums. It always makes me feel better when I feel like manufacturers are listening. I hope the message that they are hearing is that not all of us are looking for the "high dollar/high performance" solution.

There is a significant market of people who enjoy the size, weight and handling of bikes like the KXF. People like us would rather see the reliable solution that will provide longevity to the bike rather than the high performance solution. We especially would like to see the solution that has a reasonable price tag. Stainless valves and appropriate springs fit that bill. I don't want to spend around 20% of the cost of the bike just to get it to run. I could have bought a Yamaha instead of doing that.

Jimbo

[WMR]

I agree with you about not riding the bike at the red line, thats never good for any motor, however these bikes are equiped with rev limiters that are designed to keep the rpms from going too high. The other thing to understand is that on the Dyno these motors are still building power at 11000 to 13000 rpms, it would appear they were designed to rev that high. I think what KW, WMR and most of the aftermarket companies are trying to do is improve the serviceable life of the engine components. There have always been ways to improve OEM parts but I think we all have to admit the need has been a little greater with the new crop of high performance four strokes. ?

[faster48]

Dirtmachine,

It seems that I disagree with you more often than not. As for the revving issue, these are 125 class RACING machines. They ARE ment to be revved to achieve their full power potential. Do they need to be revved like a 125cc 2 stroke? No of course they don't, because they make more power off the bottom. But, they are not a open class bike. WMR is helping RACERS first, and if their work/parts can benefit casual riders then great.

I have been riding a kx250f modified by WMR all summer and the thing has been bullit proof and fast. Three weeks ago I had top 5 starts in all 4 of my motos at the Binghampton Vet/Vintage race at High Point... against 450's.

It's great that these bikes provide so much fun for so many levels of riders, but please stop saying they are not meant to be revved. Now constantly bouncing off the rev limiter is another story.. LOL ?