grinding valves


6 replies to this topic
  • martyxr6

Posted February 21, 2006 - 09:37 PM

#1

I need some advice. I am putting together my '85 xr6 engine and need to re-seat my valves. i am told that some years you don't want to grind on your valves because you will destroy the hardened coating. Can I get away with grinding my stock valves? If not, what are my options. My machinist has no knowledge on Honda valves, says I should be fine unless they are ti, but his "should be fine" answer was not as reassuring as I would have liked. Any one have a definite answer?

  • Xr650rhonda

Posted February 22, 2006 - 02:02 AM

#2

I need some advice. I am putting together my '85 xr6 engine and need to re-seat my valves. i am told that some years you don't want to grind on your valves because you will destroy the hardened coating. Can I get away with grinding my stock valves? If not, what are my options. My machinist has no knowledge on Honda valves, says I should be fine unless they are ti, but his "should be fine" answer was not as reassuring as I would have liked. Any one have a definite answer?


Buy new valves! I would however have the seats re-cut if the valves are cupped, yes the seats have the same coating, but I think most people have them re-cut and lap-in new valves with a good grinding compound. Good Luck!

  • timothypg

Posted February 22, 2006 - 04:30 AM

#3

i have an 86. my mech. said the same thing about the coating on the valves. he said seats could be ground.

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  • frankstr

Posted February 22, 2006 - 05:09 AM

#4

Steel valves...grind away. :thumbsup: Find out the tolerances for the valves though...There will be a min. thickness on the valve head margin...On that old of a engine and being air cooled I'd replace the Ex. valves...
I definitely grind the seats and its OK to lap steel valves..Not titanium :thumbsup:
I've been doing this kind of work almost 30 yrs.pm me if you like, Glad to help :bonk:

  • SDBSKI

Posted February 22, 2006 - 07:50 AM

#5

Honda recommends replacing valves, but If you just do a clean up and still have good thickness on the edges they should be ok. The Honda intakes are not great quality. Exhausts are ok. Check the difference in the factory prices. I ground my exhaust valves just enough to clean them up and replaced the intakes with some kibblewhites and a three angle on the seats.

  • martyxr6

Posted February 22, 2006 - 08:24 AM

#6

Thanks guys. I accidentally scuffed one of my seats when I was polishing the ports, that is why I wanted a valve job. Everything else looks good, so I am just going to have the seats re-done and re-use the valves. In a year or less I want to cam it. Right now I am too school poor to afford hardened rockers/and valve train parts to do the job right. When I do I will buy a fresh set of valves and maybe seats. Or maybe I will get a good job and buy an xr650r :-).

  • creeky

Posted February 22, 2006 - 08:53 AM

#7

Don't forget the valve springs, they sack out from all the heat. I've had great luck with R&D springs.





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