TOPIC:

I am trying to learn motorcycle maintenance on a 1980 kz 550 and I am at my wits end with feeler gauges. Everywhere you look, you get slightly different info.

I am trying to nail down my valve clearance and I have ordered new shims twice now (the first time I went the wrong directions in sizes... ooops)

It seems that there is a consensus between the go/no-go approach where the feeler blade can be inserted and withdrawn at some force but not in the higher blades. Of course, if you really jammed it in there, maybe, it would go but the blade runs the risk of bending. The go is your measurement, the no-go is too much.

Then, there is a consensus on the gauge sliding in and out with a "light drag." For me, this means that you can have the gauge slide in and out with some good friction and it would still be too large a blade. This seems to me a very unreliable way to take measurements and I am having a hard time developing a feel. The video below explains "the magazine test" and still that is a tough feeling to develop. I can feel a measurement of 0.2mm for the exhaust valves (in the middle of the recommended clearance) and the blade stops entering above 0.3mm. The 0.3mm measurement would be outside the range so there are some decent stake at hand here and the 0.2mm could feel right. I am just not sure.

Does anyone have any recommendations or guidance as to how I should develop a feel for it. Here is the video.


Thanks in advance

It sounds to me like you are trying to get too accurate. I'm not sure of the clearance tolerance on your bike but I think it's 0.1 mm to 0.25 mm?? If so then start with a 0.1mm feeler gauge. If it slides in easily then try 0.15. If 0.15 won't go then you are near the lower end of the range and you should probably change the shim to get a little more clearance.

If 0.1 mm won't slide in easily then you should probably go two shim sizes smaller to get back into the proper range.

On the subject of "feel" the blade should slide in easily with a slight drag.
If it needs any sort of force the blade is too thick for the gap.

zed1015 wrote: On the subject of "feel" the blade should slide in easily with a slight drag.
If it needs any sort of force the blade is too thick for the gap.

Exactly. Ed

Also on these engines fractionally wider on the clearance is better than tight .
Wide may just tick a little louder but too tight will burn valves.

I can completely understand the OP's concerns in proper use of a feeler gauge. I was fortunate having a Dad that was a tool and die maker and he gave me my initial instructions on how to use them. Things got a little fuzzy when I went to work in a auto repair shop and naturally the old timers were skeptical of my abilities, being the new kid, in setting rocker arm gaps on solid lifter cams which were quite popular back then. I would set them to what I thought was right and then an old guy would check and say, "Nope, too tight" or "Nope. too loose.". It was then that I figured out everyone has their own "touch" or feel for using something like a feeler gauge. So in a way I had to just draw a line in the sand so to speak and do it my way. I looked at it this way, if the engine ran good, didn't make too much valve noise then I did it right. If it seemed like I had one or two loose rockers I went back and checked them all. I never had anything come back at me with burned or ruined valves or valve train items. One thing that was never really taught to me, but I picked up on my own, was that it is much better to be a tad loose when doing adjustment work, especially valve adjustments, than too tight. This simple philosophy was carried over into many other areas for me and always worked well. I have run into problems when I forget that idea and use the philosophy if "some is good, more is better". When that happens look out because it probably isn't going to end well.
Rick H.

You also have to very closely read the manual on what position the crank/cams should be in and what valves to gauge at that position. If it's the first time for you, you should have the book next to you, or a copy of the required pages.

Some people just say to point the cams away from the buckets, and there are other methods, but they tend to give different results in my experience. I would use the method detailed in the factory service manual (not necessarily the Clymer manual).

In the valve train warning page, I have a summarized version.

loudhvx wrote: You also have to very closely read the manual on what position the crank/cams should be in and what valves to gauge at that position. If it's the first time for you, you should have the book next to you, or a copy of the required pages.

Some people just say to point the cams away from the buckets, and there are other methods, but they tend to give different results in my experience. I would use the method detailed in the factory service manual (not necessarily the Clymer manual).

In the valve train warning page, I have a summarized version.

Exactly! Ed