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mattf450f

Valves out of wr450f 07

10 posts in this topic

If I take the valves out of the head to replace the valve stem seals n check the valves over,since I carnt lap the titanium valves back in do I just put them back in were they came from or do I have to have the valve seats re-cut

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If I take the valves out of the head to replace the valve stem seals n check the valves over,since I carnt lap the titanium valves back in do I just put them back in were they came from or do I have to have the valve seats re-cut

You sure you even need to change the valve seals.

If so you should be able to mark which valve went where and check them for leaks with some fluid.

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In the gasket kit I got the valve stem seals so thought I might as well replace them while I'm in their.replacing the piston,rings and timing chain

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With the head still assembled, pour gas into the combustion side of the head and see if you have any valve seat leaks......you probably will, and you should get them re-cut

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If I buy steel valves can I lap them in and not have to cut the seats

 

Your asking for more grief with SS valves as they require a different spring. Still usually cut the seats for new valves.

 

Check your valves for leakage as mentioned. You could change the seals and install the same valves in the same ports. It's running that way now. If the valves have too many miles or are cupped they need replacement. However I imagine there might be many 07's running around with original valves.

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I found out the reason u carnt lap the ss valves in is because it will take of the nitride coating on the valve same as titanium

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I don't think it is a problem to lap SS valves. They should have no coating. My Kibble Whites did not.

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It depends on the manufacturer.  Older OEM Yamaha valves were not coated and can be lapped.  At least one producer of aftermarket SS valves uses TiN coatings instead of a hardening or other treatment, and should not be lapped.

 

If you need to replace a valve, you NEED to refinish the seat. Period.  Lapping won't do anything except transfer the wear pattern of the seat onto the new valve.

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