wr450 valves pulling thru

4 replies to this topic
  • walshy

Posted August 10, 2006 - 01:12 AM


When I first got this WR450 "3 years ago" I set the inlet valves at 00.20 exhaust 00.25 mil. Haven't moved at all till recently. Last check they were "inlet 00.10" :ride: "exhaust 00.25" :thumbsup: How radical is this as far as valve wear is concerned? How far can they move before its time to do something about it?
Thanks for any advice!

  • xr_man

Posted August 10, 2006 - 09:49 AM


so what your saying is the inlet has closed up by 4 thou in 3 years ??
no big deal ...re shim it !!

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  • walshy

Posted August 10, 2006 - 02:14 PM


so what your saying is the inlet has closed up by 4 thou in 3 years ??
no big deal ...re shim it !!

Well 4 thou in about 7 - 10 months that was last time I looked at them didn't move much if any for 2 years or more. Have re shimed to speck. Just check more often ya reckon xr_man? :thumbsup:

  • Desracer

Posted August 10, 2006 - 11:38 PM


How many hours of riding is that? I use a hour meter to keep track of how much time I have on the engine. You would be surprised on how hours add up. Some of my rides go 3 miles in an hour so I changed my maintenance from miles to hours by using the meter. I found that heat from going slow was able to affect the valves. Also lean jetting aka easy glowing headers affects the valves. Hi rpms for long periods and valve float the same. I have checked my 05 at 1500 miles and they were good. At 1500 miles on the 03 I had changed shims twice. Your bike seems to me normal wear, or the price for performance. I just finished a 450 Honda valve replacement, my Yamaha never looked better! The Honda's just go bad all at once and you have to replace valves just to be safe.

  • walshy

Posted August 11, 2006 - 01:03 AM


well I guess that I've done 3 to 4 thousand ks since the previous valve check, probably been riding the bike a bit harder than I used to also. hour meter sounds like a good thing too desracer, putting in some big days in the bush. I must have checked the valves 10 times over the years, just got a bit of a shock when they actually needed re shimming on the last occasion.


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