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starfish

07 wr 450 valve life

15 posts in this topic

Hey my 9 month old 07 wr 450 has 1800 miles on it and thinking of freshing it up.

Most of those miles are mid rpm single track. But about 500 miles are high rpm gp racing. I have changed the oil before every race and after three trail rides. Fresh air filter every two rides or more if needed. And I NEVER rev my engine cold!!! So I figure I will do a piston and ????? So what is valve life? I would rather replaced the valves and keepers now then after it breaks off a valve head. Yes I will be moving up a class and racing next year. Opinions please.. Thanks

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Hey my 9 month old 07 wr 450 has 1800 miles on it and thinking of freshing it up.

Most of those miles are mid rpm single track. But about 500 miles are high rpm gp racing. I have changed the oil before every race and after three trail rides. Fresh air filter every two rides or more if needed. And I NEVER rev my engine cold!!! So I figure I will do a piston and ????? So what is valve life? I would rather replaced the valves and keepers now then after it breaks off a valve head. Yes I will be moving up a class and racing next year. Opinions please.. Thanks

1800 miles i wouldnt touch it....i went 11k miles on my 06 before i sold it and it had hard baja/dual sport and desert on it....this is not a honda for crying out loud!

at min if you want to spend money, just re ring it and call it good!

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Between the four 4xx's that I've owned I've put literally tens of thousands of miles total. Probably well over 10,000 miles on my '03 plated bike and never had to do more than a minor shim adjustment on any of them. Check the valve lash, adjust as needed and then go ride. Like 123BigcoopDawg576 said it ain't no Honda!

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10,000 miles of street & dirt use on my 2003 WR450f and only required a single valve adjustment.

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Me and my son ride the piss out of Yamahas. Just change the oil, and oil filter , and clean the air filters. We try to ride every Sunday. Going on 2 and half years and no major problems. Just fork seals, tires, chains and such. But the motors are great.

You want to replace valves, by a Honda CRF. That bike will give you plenty to do.

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I lunched my trans at 3800 miles and had to split the cases. Doing so I checked everything and found all was good. I did put rings in, even though the old ones were still in spec, cleaned everything and put it back together. Keep track of your shims when adjusting valves. When you are a couple of sizes from stock, then worry about it. At 1800 miles, you still probably have about 8000 to go.

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Yeah... what are you thinking Starfish ?!?!?!? :thumbsup:

Hey, we have a nice little winter series going on up here at Pacific Raceways in Kent / Auburn starts 12/20 - MX, woods, grass and enduro-x sections included... check the NW forum for the flier... you should bring some guys up and hit it:thumbsup:

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Hey don your the guy to ask. How miles,hours, racing on your wr?

I am most worried about a valve head breaking off and destroying everything.

I talked a nationally known yamaha engine builder and they said just check for cracks in the valves them self. They are probably ok. I have held the throttle wide open in 2 and 3 gear at eddieville alot......I was on the rev limiter in 5th at the tought as nails. Yes i am worried. It seems better to replace now then repair later.. ....jim p.s I finally won at eddievile in oct. Moving up next year.

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I am most worried about a valve head breaking off and destroying everything.

I've heard of that happening at the most random times on other makes...but its usually the 250fs.

IMO if you've never needed to shim them, they're good to go. 1800 miles is still breakin it in :thumbsup: Hell I've got 1100 miles on mine to start and there is still a butt load of resistance on the kickstarter.

To the guy that lunched his trans at 3800 miles: Do/did you do clutchless shifts under power ???

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Hey don your the guy to ask. How miles,hours, racing on your wr?

I don't know:bonk: - 2 full race seasons in the NMA + 1,000 or so miles logged in the Desert at Odessa + another 1,500+ miles trail riding.

Copied post from Grayracer on the subject -

The danger with YZF's is in running any valve that has needed shimming .10mm or more smaller than its original shim for any length of time. Such valves are at risk of breaking the stem off, which can do a lot more than ruin a head.

I have check / adjusted my valves 3 times since Jan 07' and have never had to adjust more than .050 at any given time... most my adjustments were due to cam swaps (in and out:banghead:).

I never took the cylinder off to check anything... as stated by another poster, I had put thousands and thousands of miles on my 4XX's and have never had to do a "top end".

Congrats on the win! So now it's Senior Expert in the OMRA series? Long course rules... get in shape:banana:

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I've heard of that happening at the most random times on other makes...but its usually the 250fs.

IMO if you've never needed to shim them, they're good to go. 1800 miles is still breakin it in :smirk: Hell I've got 1100 miles on mine to start and there is still a butt load of resistance on the kickstarter.

To the guy that lunched his trans at 3800 miles: Do/did you do clutchless shifts under power ???

Thought I was unloading as I shifted,:thumbsup: but fifth gear shift fork thought otherwise. I now do my best to use the clutch all the time.

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I checked mine in my 07 450 at 3500 mile they were fine . it has 6500 miles on it now . I'm doing a complete overhaul now .I'm going to replace the valves with oversized stainless ones , but the titanium ones are still in spec . I'm rebuilding it now because I wrecked it and bent the shifter shaft . so it's getting whatever is worn in the tranny , new clutch packs , new piston and rings , and a rebuilt head .

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I checked mine in my 07 450 at 3500 mile they were fine . it has 6500 miles on it now . I'm doing a complete overhaul now .I'm going to replace the valves with oversized stainless ones , but the titanium ones are still in spec . I'm rebuilding it now because I wrecked it and bent the shifter shaft . so it's getting whatever is worn in the tranny , new clutch packs , new piston and rings , and a rebuilt head .

That SUCKS!!!!!!!!!

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I hurt too . I hit a deer while I was going 60 mph . I hit the deer right in the side . it bounced off the forks forward then I ran over it . I was going thru a sharp left hand turn while hitting the deer . anyhow when I ran over it I highsided the bike. it bent any broke a few things but really not much . the bike did not get hurt much at all . it did trash all the gear I had on . I landed on my shoulder and slide to a stop.

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