valve adjustment question


7 replies to this topic
  • Just_a_trail_rider

Posted June 08, 2009 - 05:09 AM

#1

Posting this message here to hopefully get more input...

I was doing my much needed maintenance on my wr450, including checking the valves. I've got countless miles on it. But I cannot imagine that it more than 4000, probably less. Power seems down a bit, but maybe that's just me really used to the bike now and able to control it better.

So I get the valve cover off and start checking my clearances.

On the intake all is good. The .102 guage slides smoothly under all the intake cam lobes. The .127 (or so) gets under the lobes with some pressure from me. I can't get the .152 feeler guage under the cam lobe no matter what I do... So I seem to be in spec.

On the exhaust however, I am checking for .20 to .25 clearance. I get the ..203 guage under the exhaust cam lobes, I have to apply a bit of pressure to get the .229 guage under the lobes. But then... I can apply some pressure and get the .254 guage under the lobes. Hmmm.... this is curious... :thumbsup: So I then start looking for the gauge that I cannot get under the cam lobe, but it turns out that I can get any of them under there by applying some pressure. Even the biggest one .635 fit under the cam lob with some pressure.

So what's the deal here, am I that strong that I'm compressing the valve springs.? Or are the valve springs soft enough where I could apply pressure from the top with a feeeler guage and compress the valve spring enough to get almost any size feeler guage underneath the cam lobe.

I guess I was expecting that it would be stiff enough that it would eventually reject a feeler guage of a certain size, just like the intake side. I did race (enduros) for a couple of years on this bike and ran it hot once or twice.

Can my valves really be that far out? It starts and runs just fine, although its down on power. But then again, I don't recall what great power should feel like.

Someone please advise me on this.

btw... I've got another more serious problem that i'll discuss in another thread.

  • matt4x4

Posted June 08, 2009 - 05:56 AM

#2

Maybe you're just that strong....
Valve clearances get tighter with time so it's not bad valves causing this - it's probably you.
Measurement is correct with almost no resistance when you slide the feeler in.

  • grayracer513

Posted June 08, 2009 - 06:31 AM

#3

So what's the deal here, am I that strong that I'm compressing the valve springs.? Or are the valve springs soft enough where I could apply pressure from the top with a feeeler guage and compress the valve spring enough to get almost any size feeler guage underneath the cam lobe.

Yes. The larger gauges are stiff enough that you can wedge them under the cams against the valve springs. You can fairly easily shove a screwdriver in there and open the valves 3~4mm if you want to.

By the sound of it, your exhaust valves are at .21~.22mm. The feeler gauge is used to determine how big the space between two parts is, not how big an object can be jammed between them.

  • Just_a_trail_rider

Posted June 08, 2009 - 07:24 AM

#4

Thanks for the info and perspective.

I'm trying to figure out why I am down on power these days. The valve check was the first thing I looked into. I'll have to start paying attention to see how much oil I am burning. I can't see any residue near the pipe nor does it smoke.

Oh well... I can't get my spark plug out, so it looks like I'm going to have to remove the head anyways. :anghead: :thumbsup: Who know what the hell else I'll find. This worries me.

I'll ride it as is for another month and then I'll tear into it. I'm hoping that I won't have any need to change the spark plug while out on the trail.

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  • KJ790

Posted June 08, 2009 - 10:18 AM

#5

Thanks for the info and perspective.

I'm trying to figure out why I am down on power these days. The valve check was the first thing I looked into. I'll have to start paying attention to see how much oil I am burning. I can't see any residue near the pipe nor does it smoke.

Oh well... I can't get my spark plug out, so it looks like I'm going to have to remove the head anyways. :anghead: :thumbsup: Who know what the hell else I'll find. This worries me.

I'll ride it as is for another month and then I'll tear into it. I'm hoping that I won't have any need to change the spark plug while out on the trail.


It sounds like your valves are in spec. It is the beginning of summer time, so warmer weather is upon us. Have you leaned out your jetting at all since it was cooler? If your jetting is too rich it will cause a decrease in power.

  • Just_a_trail_rider

Posted June 08, 2009 - 12:32 PM

#6

It sounds like your valves are in spec. It is the beginning of summer time, so warmer weather is upon us. Have you leaned out your jetting at all since it was cooler? If your jetting is too rich it will cause a decrease in power.


I'm going to do that. Now that my 450 is for dual sport summer riding only, I now ride at an average of 3000-4000 feet higher elevation. I'll lean it out using the jetting guide and see if I can regain some of my missing low end grunt. I really need this bike to pull a lot stronger up the hills.

  • clutchless

Posted June 08, 2009 - 12:42 PM

#7

http://shop.thumpert...tkit&Click=7996

  • Just_a_trail_rider

Posted June 08, 2009 - 05:22 PM

#8

http://shop.thumpert...tkit&Click=7996



:thumbsup:

have it already. thanks.





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