how to measure valve clearance

swest wrote: This thing has been hammered to death but carry on. :whistle: :woohoo:
Steve

Thanks for your permission, Steve. :laugh:

Here's something interesting to go with the conversation.
Steve
www.redlinecycle.com/Valve%20Shims.html

swest wrote: Here's something interesting to go with the conversation.
Steve
www.redlinecycle.com/Valve%20Shims.html

Actually, I've been to Redline in person, many years ago, for the purpose if buying shims. That page is discussing the big shim-over type. I never heard of the shims with the suffix labels. That's interesting.

But I have also found the aftermarket shims for the smaller bikes have size variances. I've never seen them crack or get that etched look, though.

I agree that this topic has been hammered to death. For my part in that I'll say I'm sorry and that this will be my last post in this thread.

After experimenting on my bike using all the various cam positioning methods I will say the following:

The measured clearance is influenced by whether the adjacent valve is depressed or not.

With the adjacent valve strongly depressed, the cam is shifted upwards in the head journal bearings and the lash clearance will increase by about .0015" compared to measuring the same valve where the adjacent valve is on the base circle.

That's it. I'm finished. Everyone is free to adjust the valves however they want. Key thing: adjust your valves. The exact method of positioning the cams is of far lesser importance.

Nessism wrote: I agree that this topic has been hammered to death. For my part in that I'll say I'm sorry and that this will be my last post in this thread.

After experimenting on my bike using all the various cam positioning methods I will say the following:

The measured clearance is influenced by whether the adjacent valve is depressed or not.

With the adjacent valve strongly depressed, the cam is shifted upwards in the head journal bearings and the lash clearance will increase by about .0015" compared to measuring the same valve where the adjacent valve is on the base circle.

That's it. I'm finished. Everyone is free to adjust the valves however they want. Key thing: adjust your valves. The exact method of positioning the cams is of far lesser importance.

Well, thanks for all the time and work. I'm not sure everyone realizes that one post, of this type, can take an hour or more of research.

But there is a large volume of new information in this thread.

The only thing I can say is that on the 550 head, the difference between measuring the clearance on valve, with a hard-pressed adjacent valve, or soft-pressed adjacent valve, is far less than .001", and probably closer to .0002" (as opposed to Ed's assertion that it is .0015").

loudhvx wrote:

Nessism wrote: I agree that this topic has been hammered to death. For my part in that I'll say I'm sorry and that this will be my last post in this thread.

After experimenting on my bike using all the various cam positioning methods I will say the following:

The measured clearance is influenced by whether the adjacent valve is depressed or not.

With the adjacent valve strongly depressed, the cam is shifted upwards in the head journal bearings and the lash clearance will increase by about .0015" compared to measuring the same valve where the adjacent valve is on the base circle.

That's it. I'm finished. Everyone is free to adjust the valves however they want. Key thing: adjust your valves. The exact method of positioning the cams is of far lesser importance.

Well, thanks for all the time and work. I'm not sure everyone realizes that one post, of this type, can take an hour or more of research.

But there is a large volume of new information in this thread.

The only thing I can say is that on the 550 head, the difference between measuring the clearance on valve, with a hard-pressed adjacent valve, or soft-pressed adjacent valve, is far less than .001", and probably closer to .0002" (as opposed to Ed's assertion that it is .0015").

Sorry, I lied. One more post.

When the adjacent valve is depressed it shoves the cam upward by whatever clearance there is in the camshaft journal bearings. On the 750/4 the service limit for the clearance between the cam and the journal bearing is .0075". On my bike, which as 11k miles on it, the cam shifted upward about .0015", but on a higher mileage bike with more wear on the parts, the cam will shift a good bit more, thus the clearance variation will be greater.

Bottom line: the more mileage and wear on the parts the more clearance error there will be present in the measurement by following the factory measuring method.

Why would there be a difference. That same wear would be expected on both cam caps. The whole camshaft would be raised, thus making the relative differences about the same as in a low-mile motor.

I'm making my measurements on an old worn out head. Only one of 8 valves had a different result between the two methods.

loudhvx wrote:

swest wrote: Here's something interesting to go with the conversation.
Steve
www.redlinecycle.com/Valve%20Shims.html

Actually, I've been to Redline in person, many years ago, for the purpose if buying shims. That page is discussing the big shim-over type. I never heard of the shims with the suffix labels. That's interesting.

But I have also found the aftermarket shims for the smaller bikes have size variances. I've never seen them crack or get that etched look, though.

I have a shim that has a hole in the face. I thought I had stepped on it and a piece of gavel chewed it up. Now I don't think so. It is a aftermarket shim. I don't know if I got it on eBay or jetsRus. Ether way it's frightening.
Steve

Sorry loudhvx, but one of us is missing something. To my way of thinking the adjacent valve will push the cam up in the journal clearance thus increasing the clearance measured. When the adjacent valve is not pushing up the cam will just sit on the bottom of the journal or more towards the middle.

Don't forget to factor in the thickness of the pressurised oil film on the bearing shells when the engine is running :laugh:

zed1015 wrote: Don't forget to factor in the thickness of the pressurised oil film on the bearing shells when the engine is running :laugh:

Maybe just measure the clearance with the engine idling. Of course, you gotta be quick! :laugh: :laugh: Ed

Nessism wrote: Sorry loudhvx, but one of us is missing something. To my way of thinking the adjacent valve will push the cam up in the journal clearance thus increasing the clearance measured. When the adjacent valve is not pushing up the cam will just sit on the bottom of the journal or more towards the middle.

I've been in agreement on that pretty much throughout this discussion. My results show that, and I understood your results to show that.

To summarize what I understand in this thread:
1)Measuring the clearance at different rotational positions on the base circle will give different clearance measurements because adjacent cams will be pressing on valves by varying amounts including not pressing at all.

2)Difference between the Suzuki method and Kawasaki method:
When the adjacent valves are not pushing at all, as in what we've been calling the Suzuki method, the measurement tends to be smaller by some amount. I thought you estimate the difference to be about .001" to .002". I don't disagree with that. When I checked one valve, first with no adjacent valve pressed, then with the adjacent cam pressing about 1/4 to about 1/3 of the valve travel, I did get the next feeler size to fit. This means, on that one single example, the difference was .001" or less. With the valve pressed much more, the difference may be more.

3)The Kawasaki method, valve-to-valve difference:
The Kawasaki method the adjacent valve pressing down by one of two different amounts. Half of the adjacent valves will be pressing by about 1/2 of the valve travel, while other half of adjacent valves will be pressing by about 1/4 of the valve travel. I thought you said this resulting difference is about .001" to .002". My measurements did not agree with that at all. I posted all 16 measurements, where I measured each valve with the adjacent pressed by about 1/4, then I measured each valve with the adjacent pressed by 1/2. Since only one of eight valves had an actual difference in feeler measurement, we can very roughly conclude the actual difference is about .0002", which is far less than .001".

4) Due to the difference found in 2), we both agree that it may be a good idea to aim for the low to middle end of the clearance range when using the Suzuki method. (And presumably the middle of the range when using the Kawasaki method.)

5) I contend the valve-to-valve difference in 3) is too small to matter since it's far less than .001" on the head I measured. I think that's where you disagree, and I thought you made the statement that the difference is larger, especially on older heads. The head I was measuring was old.


As I see it, we only disagree on point 3), and it's not about whether there is a difference or not, but only in the amount of difference.