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Has anyone replaced their Valve Seats?

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I may need to replace my valves yet again :devil:. I've read theories that softer valve seats may cure the cupping problems that so many of us are having. Of course SS valves were supposed to do that too :thumbsup:. Has anyone actually replaced their valve seats with a softer material with positive results?

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James, how many miles/hours did you get on your SS valves? Did you replace the springs with aftermarket high quality springs also? I'm having ESP replace our valves with kibblewhite SS valves and springs. They say that the seats will probably not need to be replaced with softer material, but they may or may not need to be cut. Their claim is that it is a spring problem that causes the valves to suck in. It's hard to find a definative answer. Hoping that they last this time.

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I've only got 2k-3k miles on these valves. I won't get to pull the head until this weekend but I can tell by the kick that I'm at 0 clearance or very clost to it.

The valves were installed before it was a common fact that they shouldn't be lapped so they were lapped when I installed them. The springs were not replaced and I didn't have any work done to the seats. The seats didn't have any defects that were visable to my untrained eye :thumbsup:.

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Hey Bill, I looked on the kibblewhite website and only saw the White Diamond valves listed for the 300. From looking at the website, it appears that only the Black Diamond valves had the hard coating to help prevent cupping. Do you know if this is correct and that your valves will be uncoated which would mean that they should be lapped?

My understanding is that coated valves shouldn't be lapped because it ruins the hard coating. I would guess that it wouldn't make a difference with uncoated valves.

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James, if you had put in new springs and not lapped them, maybe you would have gotton some more miles - maybe not. Who knows, but probably. Still, 2-3k miles is pretty good, considering the Honda and Kawazuki valve woes.

I wasn't aware that Kibblewhite had different kinds. I'll have to call the shop on Monday and check it out. I'll try to find their website also. Thanks for your input.

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Bill;

You may want to consider Kibblewhite's oversized intake valves. IF the stock valves are seating near the outer edge of the valve face, that could contribute to the cupping of the valve. Large diameter valves would relocate the contact surface a bit closer to the bottom of the valve face where the valve is thicker. Isn't that what FourStrokeWorks is doing??

Wrench on

Brewster

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Still, 2-3k miles is pretty good, considering the Honda and Kawazuki valve woes.

I know the new racing 4 strokes are having lots of problems with valves but I don't consider 2-3K miles "good". I haven't heard that the KTM's have these problems so I would think that there is a cure.

BTW: I did use a 50/50 mix of leaded race gas for a while after the install. I didn't notice any real power difference so I quite using it. Also the gas I used (VP C12) was really overkill for what I needed. I may have seen better results with a race gas that didn't have such a high octane rating. This may have been why I got that many miles on the valves ... who knows :cry:

Here is Kibblewhite's website: http://www.blackdiamondvalves.com/products.htm

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