valve replacement

i have my original valves from 03 believe it or not. im looking at kibble white valves wich i used in my 01 yz426 motor. they are saying you have to buy the spring kit as well to use them in a 450. has anybody replaced with aftermarket valves at a decent price? with that spring kit its the same as factory.

I believe the kibble white valves are steel not Ti like OEM, The steel having more mass needs different springs to compensate. So you will be paying the same price for less preformance.

IMO, when the seats are correctly finished, there is no advantage in longevity or performance to using stainless valves in a YZ450. The OEM Yamaha Ti valves last a very long time, as you can personally attest to.

SP is correct that the extra weight of stainless valves requires something to be done about valve springs. The Kibblewhite spring kit is so pricey because they try to avoid using much heavier spring pressure by substituting titanium spring retainers for the stock steel ones. It's a cool idea, but it runs the price up to the point that there's no cost advantage to the KW setup.

Aftermarket Ti valves are either more expensive, or not as good. There are some other sources of SS valves, and you can probably find a set of springs to use with the heavier valves.

I lean toward OEM replacement parts on this.

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