Considering a rebuild-TI or SS valves?

[ckulzer]

Good day,

I have 132 hours on my '03 450. I am considering a rebuild before I start the enduro season.

Any comments on Yamaha versus Aftermarket (it's the fight of the year) as I ready my wallet?

Thanks

Chad

'03 WR450

'01 TTR-L

Tons of junk that could be made into another couple of bikes - perhaps the new Honkawzukaha should start development.

[jams229]

Kibblewhite stainless would be my recommendation.

Quality product; long-lasting valves.

[ckulzer]

Jams229,

Do you have any first hand experience with the Kibblewhite products? If so, please share with the group. What benefits has the product brought to you? I am thinking that I would buy new Yamaha valves - only because I know they have worked good so far.

I am considering the rebuild as a preventative measure. I have owned the bike since new and it has never given me a problem. Just like replacing the radiator hoses and brake fluid, I am thinking that the internal bits are getting tired too.

Chad

'03 WR450

'01 TTR-L

Tons of junk that could be made into another couple of bikes - perhaps the new Honkawzukaha should start development.

[fershy]

Just a quick piece of succinct advise before you unload your cash.

"If it aint broke don't fix it."

fershy

[jams229]

Jams229,

Do you have any first hand experience with the Kibblewhite products? If so, please share with the group. What benefits has the product brought to you? I am thinking that I would buy new Yamaha valves - only because I know they have worked good so far.

I am considering the rebuild as a preventative measure. I have owned the bike since new and it has never given me a problem. Just like replacing the radiator hoses and brake fluid, I am thinking that the internal bits are getting tired too.

Chad

'03 WR450

'01 TTR-L

Tons of junk that could be made into another couple of bikes - perhaps the new Honkawzukaha should start development.

My experience is with a set of their ss valves for my CRF450X.

I replaced the two exhaust valves. Noticed no decrease in power at all,

and expect them to last a good deal longer than the titanium ones.

I don't understand the use of titanium by the way.

Hope that helps a little!

[642MX]

You shouldn't need valves at 130 hours. Properly cared for Ti valves should last 400-500 hours. I would go ahead and replace the valve springs, cam chain and rings.

[Birdy426]

From a wallet perspective, by the time you buy the KW springs, retainers, etc, it's about a push with replacing with all stock (from the TT store). At least that's the way it worked when I priced them for rebuilding my 426...(I went with stock Ti for a variety of reasons, not the least of which is the stockers performed flawlessly for more than 7000 miles.

[kyle797]

KIbblewhite makes great products we use their products in our Ducati race and street heads they are very durable.However the ducati Desmodronic valve system design uses no valve springs to close the valves so valve weight is not much of a factor. One thing to keep in mind is that the valve spring pressure keeps the valve in time with the cam if it does not keep it in time then valve float can occur and the piston can hit the valve and bend it. Titanium is used because it is 50 percent lighter than steel and lighter springs can be used to keep the valve in sequence( this is why racing cams sometimes come with new stiffer springs).So in theory a heaver stainless valve should need and come with stiffer springs. The problem with stiffer springs is that more load is applied to the cam lobes and the springs can pound the valve seats into the aluminum head and cause seat migration which is seen when valve clearances tighten up. I would inspect the stock valves for pitting on the 45 degree valve face measure the valve steam diameter and the valve length all the valve dimensions are in the service manual also measure the valve spring lengths,If the tolerances are exceeded then replace the worn parts.

[crooks420]

Some good tech info there...... Nice job.

Jesse

[Fullbore4]

Yah thanks Kyle.........good info to know.

[CRF45OX]

i asked a fabricator at work and he says that titanium IS stronger than stainless steel and it is lighter.

stainless is steel with added metals that make it stronger and has non rusting properties, but titanium is a whole new element that is stronger - although i havent drilled into titanium before so i cant talk from personal experience.

Although i also know that with worked engines in cars - you can get stainless valves but all the top end race cars use titanium.

Didnt crf's used to use stainless valves? and maybe they still do? that would probably explain their dreaded valve issues.

[CRF45OX]

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