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Anchslayer

Valve Clearance & temperature

10 posts in this topic

I just checked my valves for the first time at 270 miles. Intake are @ .102 and spec is .10 - .15. Exhaust are @ .178 and spec is .20 -.25. So I have a few questions for all you gearheads out there:

1. I know the manual says to check the clearance "cold" but my garage is near freezing @ 46 F. Will this affect the reading?

2. Assuming these clearances are accurate my exhaust is way off so it obviously needs adjustment but what about the intake, since it is right on the edge of spec should I adjust it to the middle of the range?

3. Is it normal for the valves to be this far off after just 270 miles?

Thanks to all.

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They mean check your valves when the bike is cold, meaning don't run the engine for a day then check.

It is normal to have your valves off after break-in. I adjusted mine at 500 miles now I have 4000 miles and there still good,

so, while you have it all apart and ording shims might as well make them all in the middle range (and I believe loose is better than tight)and avoid having to do it again later.

What tool are you using to get .001 accuracy?

I have the MotionPro ones and they are .10,.12,.14 ect..

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I am using a feeler gauge that has those sized blades. They are odd increments because they are equal to a normal standard measurment.

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I just checked my valves for the first time at 270 miles. Intake are @ .102 and spec is .10 - .15. Exhaust are @ .178 and spec is .20 -.25. So I have a few questions for all you gearheads out there:

1. I know the manual says to check the clearance "cold" but my garage is near freezing @ 46 F. Will this affect the reading?

2. Assuming these clearances are accurate my exhaust is way off so it obviously needs adjustment but what about the intake, since it is right on the edge of spec should I adjust it to the middle of the range?

3. Is it normal for the valves to be this far off after just 270 miles?

Thanks to all.

Dude...sounds like you are very close to spec...Your exhaust clearance is tight but its not far off. I'll bet that your exhaust is actually more like 0.202 since its so dang fresh. Even if its not you fall just a little below the clearance required so ride it and it will fall into place.

Guys at the Yamaha shop tell me that they have found clearances usually falling out of tolerance after more like 8-10,000 and really not ever before then unless some Jack doesn't take care of his bike. I put 12000 on mine before adjusting and I only needed to go up 1 size on my shims. Granted I am no gearhead and that was my first time ever...its more of a pain in the butt than its worth.. Just leave them alone for at least a few thousand miles and enjoy the ride.:cheers:

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Your clearances will generally shrink, tighten. Adjust them to spec now and they should be good for a long long time. If you adjust the intakes you will need honda shims for a crf450. They come in .025 increments while the yamaha shims only come in .05. The comments about the dealer on the other reply are just one more reason to do it yourself, most of them don't know jack and would probably charge you a bundle and adjust nothing. One more thing. A good shop might swap you shims for nothing.

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Ditto on the bike being cold, not the temperature. As to valves. Do them to the minimum of what the clearance is and it will run and produce better for you. As to being in the middle of the clearance - you can but I wouldnt. You are in there so do it right the 1st time. A tight valve will provide the highest lift, which will make it breath better. If they are all adjusted correctly at the minimum it will give you better response. It is worth the time to measure them out to thee closest you can. Once they are in, it will give you probably thousands of miles before going out of adjustment again. When the go out of adjustment it is usually tighter. Also, be sure to use a torque wrench on the cam caps and make many small adjustments to build it to the, I think 7 lbs. of torque. Good luck, Jason

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Ditto on the bike being cold, not the temperature. As to valves. Do them to the minimum of what the clearance is and it will run and produce better for you. As to being in the middle of the clearance - you can but I wouldnt. You are in there so do it right the 1st time. A tight valve will provide the highest lift, which will make it breath better. If they are all adjusted correctly at the minimum it will give you better response. It is worth the time to measure them out to thee closest you can. Once they are in, it will give you probably thousands of miles before going out of adjustment again. When the go out of adjustment it is usually tighter. Also, be sure to use a torque wrench on the cam caps and make many small adjustments to build it to the, I think 7 lbs. of torque. Good luck, Jason

Why would you shim on the tight side of the spec when given a choice? Like you said, these things tighten up as they wear, so don't you think you're somewhat defeating the purpose of the re-shim? Unless of course, you like tearing into the engine more frequently. The textbook sign of tight valve clearances is hard starting, so I'm confused as to why you'd want to invite this problem sooner. Granted, once they're re-shimmed after break-in, the next time you do it is likely going to be a long way off. Is that your point? If so, it sounds like something of a gamble to me :cheers:...SC

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Ditto on the bike being cold, not the temperature. As to valves. Do them to the minimum of what the clearance is and it will run and produce better for you. As to being in the middle of the clearance - you can but I wouldnt. You are in there so do it right the 1st time. A tight valve will provide the highest lift, which will make it breath better. If they are all adjusted correctly at the minimum it will give you better response. It is worth the time to measure them out to thee closest you can. Once they are in, it will give you probably thousands of miles before going out of adjustment again. When the go out of adjustment it is usually tighter. Also, be sure to use a torque wrench on the cam caps and make many small adjustments to build it to the, I think 7 lbs. of torque. Good luck, Jason

You are REALLY optimistic if you think that setting your valve clearance to the tight side of the specification is going to yeild you increased performance. In laboratory test maybe. In real life Please. The whole point of valve lash adjustment is engine service life. Besides you dont have that fine of adjustment with Yamaha shims anyway. If you want to go faster buy an exhaust system otherwise service the valves and go ride.

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I'm going off of what those greater than I have stated and from a small amount of experience. Of course, if we are taking good care of our bikes, then, well, wouldnt we be into the engine anyway. We must be checking the valves more frequently than believing that once adjusted we can go 5 or 10 thousand miles without an adjustment. The putting in of shims or pads is only a little more work than a valve check and I would hope we will do it somewhat frequently. Hey, the guy asked my opinion, and well, I gave him one. I do think small increments will make a difference in the way the bike responds. It made mine a little quicker on the response, and by the way, I do plan on getting an exhuast system someday when I can afford one. You are right though, I am guilty of being optimistic! Please dont tell anyone! Thanks, Jason

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