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jimbopitts

450 valves

12 posts in this topic

anybody tried stainless steel valves?I heard they are more durable but your bike will rev slower because of the weight.

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Are you having a durability issue with your Ti valves? Do you know anyone who has? My '03 has not yet needed its first adjustment. This is not a Honda.

But be that as it may, I would avoid Kibblewhite for a variety of reasons, and use instead valves from Ferrea, available through Ron Hamp Cycle. I don't think you will see a difference in the rev range, but you will need heavier springs because the valves are roughly twice as heavy. RHC can provide those as well, or you could experiment with springs for a 2000 YZ426, which had SS valves. I don't know if they will fit and set up correctly, but they might, and they'd be very inexpensive.

For more insight as to why not KW, read:

http://www.thumpertalk.com/forum/showthread.php?t=358006&highlight=kibble

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no, i do not have valve issues, 1 of my intakes were tight, the right side. with the bike facing forward. i haven't heard of any problems with the ti's. just wondering for the future. thank you

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it was only 1 thousanth off, or .07 mm. The stock pad was a 189 and my mechanic at my shop gave me a 185 and it put it right at .15 mm.

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That happens sometimes. It was probably a matter of a valve settling into a seat, and it should now stabilize clearance. Watch it for a little while to be sure it does.

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On reviewing this more carefully, I see a contradiction:

If you had a valve at .07mm, and went from a 189 to 185, you would now have .11mm clearance. If you now actually have .15mm, that means that you had .11mm before you shimmed, and the valve in question was perfectly fine. They are built to the low end of the clearance range at the factory. One or the other of your measurements has to have been wrong. An .04mm shim change will not move a valve .08mm.

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I am 99% sure I measured right. At TDC only the feeler gage that fits will fit. I could be wrong but, I didn't think the pads measured at .01mm per number. Either way my valve is in spec, but I will be more careful when I check next time.

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The service shims sold by Yamaha are only available in .05mm increments. Honda sells them in .025mm increments, but they are marked only down to the second decimal. What is actually a 1.875mm shim is marked 188, and a 1.825 is marked 182.

But the shims that Yamaha uses at the factory are made in .01 increments, so the odd numbered ones you see when you first open up a new YZF engine are of those sizes. Hang onto them if you can.

In checking valves, it is not the largest gauge that will fit, because you can almost always force in a gauge one size larger than the actual clearance. It is the the gauge that "feels" (there's that word) like it just fits that indicates the true clearance. :ride:

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Again, thank you for the info. Whats your local track? In the L.A. area I like glen helen or cahuilla creek.

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