In anticipation of doing a valve job, I bought a no-name Chinese digital caliper on eBay.  Accuracy stated is 0.02mm (I don't know whether that's plus/minus, to the nearest two hundredths, etc).  I thought this might not be accurate enough, and have looked into "good ones" at grainger.  Much to my chagrin, the $40-$50 models have the same stated accuracy as the no name I bought (and are made in china, so i'm assuming probably the same thing with a brand stamped on it).  The ones accurate down to .001 are pushing $200 (ouch).

So, for the sake of brevity, how accurate do I need my caliper to be?  Is what I bought adequate, or should I really look into one of the upper end models?  I'm trying to be cost-conscious, but at the same time don't want to cheap out now and regret later.

I didn't get a caliper till 4-5 years ago, by that time I prolly had adjusted 5-6 times on my 89 and atleast 3-4 more bikes with 1 a piece minimum. You need feeler guages, not need a caliper ... BTW the adjustment kit has a caliper - well had a caliper, and the whole kit went awol one time ... no clue what its location/situation is now.

Cool.
Buddha.

Cool...have feelers on the way from Deutschland.  Saw kerry's video and figured I'd need the caliper to verify the thickness of the shims, but I guess you can just keep sticking them in there until it comes to within tolerance.

Hey, this is kind of a side question, but can one open it up to do the valves, figure out what shims you need, and leave the top end disassembled while you're waiting for them to arrive (maybe cover w towel or something) or is that a bad idea?  Actually...prob not that difficult to just screw the valve cover back down.

Quote from: Pelikan on October 13, 2010, 09:51:05 PM
Cool...have feelers on the way from Deutschland.  Saw kerry's video and figured I'd need the caliper to verify the thickness of the shims, but I guess you can just keep sticking them in there until it comes to within tolerance.

Hey, this is kind of a side question, but can one open it up to do the valves, figure out what shims you need, and leave the top end disassembled while you're waiting for them to arrive (maybe cover w towel or something) or is that a bad idea?  Actually...prob not that difficult to just screw the valve cover back down.

Yeah, it's cool. Quite common practice, actually, to have rags covering areas and shoved into holes where you don't want things to fall in or dust/dirt to get into.

Quote from: Pelikan on October 13, 2010, 08:47:13 PM
In anticipation of doing a valve job, I bought a no-name Chinese digital caliper on eBay.  Accuracy stated is 0.02mm (I don't know whether that's plus/minus, to the nearest two hundredths, etc).  I thought this might not be accurate enough, and have looked into "good ones" at grainger.  Much to my chagrin, the $40-$50 models have the same stated accuracy as the no name I bought (and are made in china, so i'm assuming probably the same thing with a brand stamped on it).  The ones accurate down to .001 are pushing $200 (ouch).

So, for the sake of brevity, how accurate do I need my caliper to be?  Is what I bought adequate, or should I really look into one of the upper end models?  I'm trying to be cost-conscious, but at the same time don't want to cheap out now and regret later.

In theory, you don't need a dial caliper at all............the shims are marked...........you are just verifying that they are marked correctly...........

Ultimately you will check the clearances with a feeler gauge.........the feeler gauge must be accurate, but they are...even fairly cheap ones.............

If the shims were marked wrong, then when you change the shim, the feeler gauge would show incorrect clearance.....all you can do is go up or down in shim thickness and try the feeler again.........

Cookie

Quote from: Pelikan on October 13, 2010, 08:47:13 PM
In anticipation of doing a valve job, I bought a no-name Chinese digital caliper on eBay.  Accuracy stated is 0.02mm (I don't know whether that's plus/minus, to the nearest two hundredths, etc).  I thought this might not be accurate enough, and have looked into "good ones" at grainger.  Much to my chagrin, the $40-$50 models have the same stated accuracy as the no name I bought (and are made in china, so i'm assuming probably the same thing with a brand stamped on it).  The ones accurate down to .001 are pushing $200 (ouch).

So, for the sake of brevity, how accurate do I need my caliper to be?  Is what I bought adequate, or should I really look into one of the upper end models?  I'm trying to be cost-conscious, but at the same time don't want to cheap out now and regret later.

.02mm = .00078 inches that's good enough. the one kerry used in the video is a .001 or .0005 model. you can pretty much consider the .00078 and .0005 models to be accurate to .001. those increments are just useless, prob more of a marketing thing.

"The ones accurate down to .001 are pushing $200 (ouch)."
i think you mean the .0001" models. not necessary for this job. you'll prob never find a use for that kind of accuracy unless your a machinist or engineer.

OK you cannot stick a shim and measure it, it will not sink all the way, it will float on the oil in the bucket. However they have numbers on them, you would be writing it down in a notebook as to what number you have in what bucket and upon measuring it you can swap the right shim in first time. Done. A valve job is 20 mins ... max, and that includes the 4 beers the buddha will drink when doing it. Minimum 4.
Cool.
Buddha.

Get hold of a cheap metric micrometer, far more accurate than a vernier (very-near) caliper 

Yeah, a vernier calliper is the wrong tool for the job, you need a micrometer.

I agree with The Buddha 100% as well... Your primary tool should be a set of feeler gauges. I like to use a micrometer to confirm that the shims are the same size as their stamp would indicate... Although it isn't really necessary unless the stamp has been worn off - mine have always been correct.

Quote from: burning1 on October 14, 2010, 11:29:18 AM
Yeah, a vernier calliper is the wrong tool for the job, you need a micrometer.

I agree with The Buddha 100% as well... Your primary tool should be a set of feeler gauges. I like to use a micrometer to confirm that the shims are the same size as their stamp would indicate... Although it isn't really necessary unless the stamp has been worn off - mine have always been correct.

For some reason I always thought it was the shims that wore down.  Is it something else in there, like the cam, or the valve itself?

When I said stick the shim in and measure I meant like Kerry does in the video where he rotates the cam a few times to force the oil out...or will that still not work?

Quote from: Pelikan on October 14, 2010, 12:34:28 PM
For some reason I always thought it was the shims that wore down.  Is it something else in there, like the cam, or the valve itself?

I put over 80k miles on my 97 GS and never changed an intake valve shim and got the same measured clearance every time.  Now with over 80k miles on my 02 GS I still have the same intake valve shims in it that it came with and expect to at 100k miles. 

Exhaust valves wear into the seats if run too tight not allowing enough cooling seat time.  On my 97 GS one of the exhaust valves was down to a minimum 2.15 shim at 80k miles after repeated shim changes to smaller shims.  One of my 03 GS exhaust valves started the same pattern and I increased my exhaust valve clearance to a little more than Suzuki specs and stopped the valve wear.  Expect to hit 100k miles with the current mid size shims all around with little or no further shim changes.  Stay tuned for a couple more years for a complete report.   

The shims and cams did not wear on my 2 GS's, only the exhaust valve seats and faces wore.  I measure shims with a good quality 1" mike and have yet to find one not exactly as marked.  Here's the whole record:

http://img.photobucket.com/albums/v443/jcp8832/valveclearances.jpg

Quote from: The Buddha on October 14, 2010, 07:31:30 AM
OK you cannot stick a shim and measure it, it will not sink all the way, it will float on the oil in the bucket. However they have numbers on them, you would be writing it down in a notebook as to what number you have in what bucket and upon measuring it you can swap the right shim in first time. Done. A valve job is 20 mins ... max, and that includes the 4 beers the buddha will drink when doing it. Minimum 4.
Cool.
Buddha.

As they say..."There is more than one way to skin a cat!"

Repair manual page 2-7 addresses the issue of oil under the shim when measuring..........they say to simply rotate the engine to squeeze out the excess oil.............then measure the actual clearance with a feeler.

Repair manual also makes no mention of using a caliper or micrometer to measure the shims....just to trust the shim as marked........

Cookie

Quote from: The Buddha on October 14, 2010, 07:31:30 AM
OK you cannot stick a shim and measure it, it will not sink all the way, it will float on the oil in the bucket. However they have numbers on them, you would be writing it down in a notebook as to what number you have in what bucket and upon measuring it you can swap the right shim in first time. Done. A valve job is 20 mins ... max, and that includes the 4 beers the buddha will drink when doing it. Minimum 4.
Cool.
Buddha.

LOL..........I tell you what....come on over and do my valves clearances, and I'll buy the beer! (and not just 4...I'm not cheap... I'll get you the whole 6 pack!)

I figure the valve adjust will take me about 4 hours, and a couple of days extra if I have to order shims!

Cookie

i bought a digital harbor freight one(micrometer) accurate to +/- .0005 for $20. a layer of oil can add .001 to the shim.

Quote from: tucsondude on October 14, 2010, 05:21:55 PM
i bought a digital harbor freight one(micrometer) accurate to +/- .0005 for $20. a layer of oil can add .001 to the shim.

Right......But..........

The shims come in every 0.05mm       so an extra 0.001 doesn't matter   maybe wipe the shim clean before measuring?

Or just go by the markings on the shim and forget the micrometer?

Cookie

Quote from: Pelikan on October 14, 2010, 12:34:28 PM
For some reason I always thought it was the shims that wore down.  Is it something else in there, like the cam, or the valve itself?

When I said stick the shim in and measure I meant like Kerry does in the video where he rotates the cam a few times to force the oil out...or will that still not work?

Nope. The valves themselves start to wear into the heads. If the clearance becomes too tight, the valves can no longer seat against the surface of the head, and will neither seal the engine completely, nor will they cool properly. Valve clearance also has a small impact on lift, duration, and valve overlap... Although in those cases, a tighter valve will offer slightly better top-end performance (until the valve gets so tight that you melt it, or loose compression.)

When you perform a valve adjustment, you should measure all your valves before removing the cams or shims from the engine (I pull the cams. I do not personally use the Suzuki tool.) So long as you measure the shims before removing them, there should be no need to seat the shims. The only time it's necessary is during the post adjustment inspection; after making any adjustment you should always remeasure the clearances before you re-install the valve cover, just to be sure.

As per GSJack's comments: Run your exhaust valves at least .05mm wider than the factory indicates. The factory clearances on the exhaust side are way too tight. In doing so, you can probably drop back to a 8K adjustment interval, and if that looks good, go all the way to 12 or 16K.

Quote from: burning1 on October 15, 2010, 12:05:31 PM
As per GSJack's comments: Run your exhaust valves at least .05mm wider than the factory indicates. The factory clearances on the exhaust side are way too tight. In doing so, you can probably drop back to a 8K adjustment interval, and if that looks good, go all the way to 12 or 16K.

This agrees with the conventional thinking back in my air cooled VW days...........valve too tight = big trouble.. possible to burn exhaust valve....

Valve too loose may make some noise, may hurt performance just the slightes bit, but will not burn valves...

Factory says exhaust valves from .03MM to .08mm........so you're saying go one size smaller on the shim giving clearance of .08mm to .13mm ?  Too bad they don't make between sized shims....then you could get the exhaust to like .07mm or .08mm or .09mm........

Cookie

I set my intakes to the factory .001-.003" and my exhausts to .003-.005" which is .002" (.05mm) larger than factory spec.  I had a 82 CB750K with shim over bucket valves and the spec was .002-.005" (.06-.13mm) for both.  The CB was redlined at 9500 rpm and I rarely if ever go over that on the GSs, no point in it with a stock GS that has a HP curve that drops off fast after 9k.  That's plenty of range for the standard .05mm increment shims.

Quick question..of all the people here does anyone have prior VW 1600cc Air cooled valve adjustment experince? I am just curious if anyone can compare the two for me. It seems to me on the GS it is a simple process. But reading this is seems to get more complicated the more it is explained.