Valve Tappet clearance is too tight, yet Shim is loose?

[1_v8_merc]

Well pretty much what the title says.
I just bought a motorcycle valve gauge, and the thinnest one I have "0.05mm", but it just WONT fit under any of the lobes!

Yet is appears most of the shims are slightly moveable!
(i found one that wouldn't move with the Lobe in proper position.)

I have checked about half of the lobes so far and can't fit the feeler gauge in there.
Im sure the lobes are at the correct angles.....

Is "0.03mm" really THAT much thinner than "0.05mm" ?


Im seriously worried guys......i hope this bike isn't about to take a huge **** and blow some valves.

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Anybody have any ideas.

I can get pictures or even video clips if you really want.

 

[hampshirehog]

Is "0.03mm" really THAT much thinner than "0.05mm" ?

It's 0.02mm thinner! Sorry, I know it's obvious. These tolerances are pretty small so it does make a difference.

Try and get hold of a set of gauges that go down to .003, though if you've got no clearance on one shim you'll need to change at least one. You could pull your shims one at a time and check the thickness and swap them about and see what clearances you can measure - minimum is .003, max is .008 though you can go to .01 safely.

Don't spin the cams when you've got a shim pulled out - you can damage the cam lobe on the bucket. You either need a spare shim, ideally a very thin one (makes calculating shim size requirements easy) or you can at a pinch replace the removed shim with a coin of suitable diameter and thickness (pass on your coinage - an old florin works here). Use the removed shim to swap with the next one pulled out and so on.

 

[Steve]

Is "0.03mm" really THAT much thinner than "0.05mm" ?

Yep, it's almost HALF as thin.

Also keep in mind that the 0.08mm maximum clearance is about the thickness of a piece of paper.
The 0.03mm minimum clearance is just over one third of that. :-\\\

If you can still rotate the shim and bucket, you are not likely in danger of hurting anything, but you really should get a proper set of feelers. You have a copy of my spreadsheet, it will handle either inch or metric inputs. For those few that don't yet have a copy of my spreadsheet, using metric feelers considerably helps with the math and logic of figuring out what you need. The 'sheet just does the math, then keeps record from one service interval to the next.

Also note that if you do use inch feelers, enter the INCH numbers on the 'sheet, not the METRIC approximations. If you have both measurements on the feeler, it's likely an INCH set.

.

 

[BassCliff]

Hi,

I was able to find a decent feeler gauge set at my local auto parts store. It goes down to .04mm and has .01mm increments. If the .04mm blade doesn't fit then I swap the shim. I like running on the loose end of the spec, maybe even a little over, as Mr. hampshirehog suggests, up to .10mm. (Let's be sure we are measuring in millimeters and not inches and we have the proper number of decimal places.)

In inches the range is something like .001" to .003". (I'd rather use millimeters; .03mm - .08mm.)

If you can spin the bucket under the lobe, at least you have some clearance. But a more accurate measurement device is essential. You can certainly use what you have but you are losing some accuracy. What other gauges do you have going up from .05mm? .06mm? .07mm? .08mm? .09mm? .10mm?


Thank you for your indulgence,

BassCliff

 

[1_v8_merc]

I have like 4 different feeler gauges, but they all look too thick.

I have one that says this on it.....

I has .0015 and .038mm on it.....but that's too thick?
It feels almost the same thickness, but i don't think that'll work.



Damnit, why is it when I walk into the cycleshops asking for a gauge that reads .03mm to .08mm, they ALL look at me like im speaking in german or something.....do these idiots really know anything?

Or either that, I just have some bad luck around here.....


Im gonna run out to another shop....

 

[Steve]

Ignore the LOOKS or the FEEL, go for what's printed on it.

That one that says 0.0015 and 0.038mm is the perfect feeler for your minimum.
It is ever so slightly larger than the minimum clearance.
If that one does not fit, it's time to change the shim anyway.

Don't let the 15 and the 38 confuse you. Look at the whole picture.
That 38 is out to the third decimal point, 0.038.
The minimum clearance is 0.030. See? 38 is bigger than 30.

Since there are inch measurements on your feeler, use them on the spreadsheet, but remember ... you don't need the decimal for most entries. I say "most", because you might find that the 0.0015 fits, but the 0.002 does not, so you would enter 1.5 on the sheet. As noted in the instructions, you only need to enter the number of thousandths, not the actual measurement. Same thing with 0.0025. Most feeler sets don't have the in-between sizes above 0.003, but that's bigger than we should be running anyway.

.

 

[1_v8_merc]

Ignore the LOOKS or the FEEL, go for what's printed on it.

That one that says 0.0015 and 0.038mm is the perfect feeler for your minimum.
It is ever so slightly larger than the minimum clearance.
If that one does not fit, it's time to change the shim anyway.

Don't let the 15 and the 38 confuse you. Look at the whole picture.
That 38 is out to the third decimal point, 0.038.
The minimum clearance is 0.030. See? 38 is bigger than 30.

Since there are inch measurements on your feeler, use them on the spreadsheet, but remember ... you don't need the decimal for most entries. I say "most", because you might find that the 0.0015 fits, but the 0.002 does not, so you would enter 1.5 on the sheet. As noted in the instructions, you only need to enter the number of thousandths, not the actual measurement. Same thing with 0.0025. Most feeler sets don't have the in-between sizes above 0.003, but that's bigger than we should be running anyway.

.

Alright thanks alot, it's more clear now!

Haha, I knew that .0015/.038 felt thinner than the .05mm one, but I just got confused by the extra "0's" in there.

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But I measured it, and it's not looking good!
The .0015/.038mm only fit under TWO lobes.

The Exhaust#1 only fit the .038mm
The Exhaust #2 accepted the .05mm, but it was a little tight.

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Im going to look at the spreadsheet and figure this out....i honestly didn't look at the spreadsheet much, i was confused by it before, but I understand it better now.

Looks like Im going to go out and buy a micrometer, i've been looking for an excuse to get one...here it is.lol

 

[bwringer]

"Bikemaster" markets a set of metric feeler gauges that go down to .03mm. You'll find them in most motorcycle shoppes, and they're well worth the measly $9 or so.

It's very easy to get confused between inch and mm measurements, so a metric set of gauges is essential. .001" is about .0254mm, so many sets of inch gauges only have two or three in the correct range.

It's also embarrassingly easy to get two thin feelers stuck together with oil surface tension, so before you get too panicked about zero clearances, double-check to make sure the blades aren't stuck together. I seem to do this about two or three times with every valve check.

Lastly, just mentioning this, but if the shims have ANY horizontal play whatsoever, you will need to change them for the proper Suzuki shims.

Common Kawasaki shims are 29mm in diameter, and Suzuki shims are 29.5mm. It's VERY, VERY common for shops and other clueless folk to get these mixed up, or figure that they're close enough.

The problem is that shims are mostly held into the bucket by surface tension at high RPM. With an ill-fitting shim that can move around, this can lead to disaster pretty quickly.