Valves out of wr450f 07


9 replies to this topic
  • mattf450f

Posted October 11, 2014 - 11:24 PM

#1

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

  • stevethe

Posted October 12, 2014 - 08:51 AM

#2

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.

  • mattf450f

Posted October 12, 2014 - 12:11 PM

#3

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

  • Krannie McKranface

Posted October 12, 2014 - 03:23 PM

#4

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



  • mattf450f

Posted October 17, 2014 - 10:54 PM

#5

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

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  • stevethe

Posted October 18, 2014 - 06:58 AM

#6

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.



  • mattf450f

Posted October 18, 2014 - 05:14 PM

#7

Thanks

  • mattf450f

Posted June 11, 2015 - 01:39 AM

#8

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

  • stevethe

Posted June 11, 2015 - 04:37 AM

#9

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



  • grayracer513

Posted June 11, 2015 - 11:24 AM

#10

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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