Valve adjustment bad move!

[gs850cmc]

Hello and thanks so much in advance for any assistance! I have a 1980 GS 850G (45K miles) that runs (at least it did) and I'm undertaking my first valve clearance adjustment. Initially I measured the clearance as described on Bass Cliff's site and found that all clearances were less than .004mm..Is this possible? My big screw up is that I turned the engine with two shims out (#4 intake, #1 exhaust) I immediately noticed that the cam lobes were scored on the edges....I so wish I hadn't done that. I'm hoping that when all is said and done this won't affect overall performance. My other question is it safe to rotate the cam with the ignition button? Basically, I have been tapping the starter to position the lobes and this has worked well except for not having the shims in. So far #4 ex=2.65, #4 in = 2.6, #1 ex = 2.55, #1 in = 2.57 (measured w/cal), and #2 ex = 2.6, and for none of them can I slip a .004 mm feeler inderneath. Also I had attempted to remove the #3 in shim but had some trouble and left it for later, when I came back apparently it wasn't seated, so when I tapped the starter..ping (loud ping) the shim snapped in two pieces. I need to get better at this in a hurry.

Thanks again for the help!

 

[spwalker09]

When you do a valve adjustment I'm pretty sure you're supposed to rotate the crank using the bolt on the end of the timing wheel, under the ignition cover; do NOT use the starter.

Are you sure you're not using a .04mm feeler? .004mm seems awful tight (I didn't know they made feelers that small too )

I'm not as experienced on GS's as the guys here, but I'm going through my first valve adjustment on my bike, and I'm going by the shop manual that I have. It would be handy to have one of those to see what the proper procedure is to rotate the cams, because they have to be in a certain position to measure clearance. Make sure you didn't F-up the bucket, or the cams (you mentioned some scoring, thats probably not good), and try not to rotate the cams without any shims in there!

 

[Guest]

Don't turn the engine over with the starter - put a 19mm box wrench on the crank end, located under the points cover & turn it over by hand.

Don't turn the engine over without a shim in the shim bucket - some members here use an extra shim (thin) to use as a "placeholder" so they can swap out different shim sizes.

You need a smaller set of feeler gages (down to at least .03mm). However, if you can still spin the shim in the bucket then you still have some clearance.

 

[Steve]

Are you SURE that shim only snapped "in two"? :-k

I had that happen on a previous bike, the shim went into LOTS of pieces.

After a couple hours of fishing with a magnet, then careful re-assembly, I felt confident to finally be able to turn the engine.

I agree with the others, you are not using a .004 mm feeler. Let's face it, .04 mm is already just half the thickness of a piece of paper, and you want to go to one-tenth of that?

Also be VERY SURE whether you are using INCH feelers or METRIC feelers. If your smallest feeler says 0.0015" / 0.038 mm, you are using INCH measurements. The metric number on there is an approximation. If, however, your feelers actually say 0.04 mm, you probably have metric feelers. Metric feelers are preferred, but not absolutely mandatory.

May I also invite you to follow the suggestion at the end of my sig. It's a handy tool, used by many. (330 and counting)

.

 

[gs road racer]

When you do a valve adjustment I'm pretty sure you're supposed to rotate the crank using the bolt on the end of the timing wheel, under the ignition cover; do NOT use the starter.

Not the bolt but the "nut" behind it you can inadvertently over tighten or loosen the bolt by using it. I think the bolts head is 12-13mm and the nut is 19mm.You should have the suzuki shim removal tool!! It's probably only $20+

 

[BassCliff]

Hi,

Always turn the motor forward (clockwise in this picture) like this:

I guess I'm going to have to edit my valve adjustment guide and put "DO NOT ROTATE THE ENGINE IF THERE ARE SHIMS MISSING!" right at the top.


How can you position the lobes properly using the starter button? That doesn't seem convenient or accurate.

Keep us informed.


Thank you for your indulgence,

BassCliff

 

[Suzuki_Don]

If You Want To Save This Situation

If You Want To Save This Situation

You will need to remove the cam chain tensioner following the instructions in the manual. And then loosen the cam cap bolts for the affected camshaft until the cam can be lifted enough to slip the shim in place. You will need to undo both cam caps and loosen the bolts sequentially. If you don't know what that means then get back to us.

Then refit the cam chain tensioner following the manuals instructions, then rotate the motor using the 19mm nut under ignition cover and check the timing is correct for both camshafts.

If there is anything you don't understand, get back to us for further explanations.

 

[Steve]

You will need to remove the cam chain tensioner following the instructions in the manual. And then loosen the cam cap bolts for the affected camshaft until the cam can be lifted enough to slip the shim in place. You will need to undo both cam caps and loosen the bolts sequentially. If you don't know what that means then get back to us. ...

Actually, since you are going to go through the effort of removing the cam to be able to insert a shim,
take just a few moments more and simply lift out all the shims to inspect and record their sizes.

NOTE: this is not the recommended way of doing it routinely, but since you are already there, ...

.

 

[Suzuki_Don]

Actually, since you are going to go through the effort of removing the cam to be able to insert a shim,
take just a few moments more and simply lift out all the shims to inspect and record their sizes.

NOTE: this is not the recommended way of doing it routinely, but since you are already there, ...

.

STEVE I didn't mean to remove the camshaft completely, only loosen it so the shim could be replaced to prevent further damage to the camshaft lobes.

 

[gs850cmc]

Wrong feeler guage

Wrong feeler guage

Thanks to all for your quick replies, I misunderstood the type of feeler gauge that I was using, it is in inch measurements with metric approximations. I am learning though..I don't believe that it will be necessary for me to lift the cams as all of my buckets do turn and I have the Shim tool. The shim that I busted came out in two pieces such that when I put them together they were a perfect fit with nothing missing. I will as a precaution scope the bucket and surrounding area with a telescoping magnet just to be sure. I did spin this bucket and it appears to be intact with no obvious marks. Is there some other reason that I'm missing that would require me to lift up the cams? I hope not, I don't want to mess with that. I will be sure to turn the engine with a wrench even though tapping the starter did allow me to place the lobes in the recommended position(s). I'm just P'off that I spun the the thing without two shims in place. Don't feel bad for not having it in the shim adjustment help sheet. It is an excellent resource..thanks!!! And the professional shop manual that I have (Clymer) makes no mention of this important fact. Although it is pretty obvious now, I shouldn't have missed it. Given the overall surface area of the cam lobe that actually makes contact with the shim is untouched, I'm hopeful that this misstep will not affect valve operation. Well now I need to get a correct feeler and one or two place holder shims (thanks for this tip). Will let you know how it turns out

 

[Suzuki_Don]

Charlie, I would be very suspicious if you can depress the valve shim bucket with the Suzuki tool and then be able to insert the shim. When you try to do this function without a shim in place the tool overhangs the internal diameter of the bucket and therefore you cannot fit a shim into the bucket as the tool is in the way.

 

[oldgsfan]

OK, I am like the LAST person to give any mechanical advice because I am still far down the learning curve..

However, I did do this EXACT same thing this past weekend on my first valve adjustment, also to my 1980 GS850G.

I rotated the engine with one shim out, not realizing you weren't supposed to do this. I sure know this now!

Well, I was able to lift the cam up with the shim replacement tool just enough to squeeze in the shim and breathed an enormous sigh of relief. It was nervewracking, but it was possible.

After that, I had no other problems with the valve adjustment.

Good luck, Charlie.

Don't feel too bad. You're right.. the manual says nothing about rotating without a shim in place and, yes, you would think it would be an obvious no-no, but just know you aren't alone. We should form a support group for garage mechanics who have done this.

 

[Suzuki_Don]

We should form a support group for GARAGE MECHANICS who have done this.

Or is that HOME MECHANICS.

 

[oldgsfan]

well, in my case, i'm using the term mechanic very loosely..

 

[Suzuki_Don]

Yes I think most of us are what we call in Australia "Backyard mechanics". But we do alright for being untrained.

 

[2BRacing]

Charlie, I would be very suspicious if you can depress the valve shim bucket with the Suzuki tool and then be able to insert the shim. When you try to do this function without a shim in place the tool overhangs the internal diameter of the bucket and therefore you cannot fit a shim into the bucket as the tool is in the way.

I have found it helps to dip the curved end of the shim tool into some engine oil before depressing the bucket, because it then just "slides" into position with a firm downward press. If the shim tool is placed correctly next to the cam lobe, the "edges" on the shim tool prevent the bottom part from overhanging the area where the shim must go in. I have attached a picture from the manual showing this detail clearly. Perhaps the shape of non-OEM shim tools is not exactly correct? I have a genuine Suzuki tool and it just "fits like a glove". It should never be necessary to have to loosen the cam to insert the shims and I do not recommend doing that. Just too many other potential problems with possible slipped chain etc IMHO.

+1 on using the larger 19 mm on end of crank to turn engine over, and removal of spark plugs will result in no "stress". Also +1 on not using starter to turn engine over.

 

[Suzuki_Don]

As can be seen in your diagram it is the shim that prevents the tool from coming too far in on the bucket surface. When the shim is not in place then it is extremely difficult to guess the correct position for the tool so a shim can be fitted. If you observe the diagram closely then you will see what I mean.

 

[gs850cmc]

parts on the way

parts on the way

Thanks again to all for the support and ideas. I should be getting my correct feeler and a few assorted shims by Tuesday. Then I will hopefully get to check things out the right way and maybe even get up and running

 

[gs850cmc]

Cam issue

Cam issue

Was back in the garage this morning, wishing I had my shims and feeler. But I did take off the signal gen cover and I can now see how easy it will be to rotate the cams with a wrench (19mm). I have a question, since I burred the edges of a couple of cam lobes, do I run the risk of serious engine damage when I button everything up and try and run it? There is no metal filings or other debris laying around or on the edges of the lobes themselves.

Thanks,

Charlie

 

[oldgsfan]

When I shaved one of the lobes, I used a magnet and cleaned around in the bucket to remove all the metal shavings and basically did the best cleaning job I could.

It's been a week now since I did my valve job and I've not noticed anything that I can attribute to my mistake.

I am dealing with a bogging issue at 65 mph, but doubt that's got anything to do with the trimmed lobe.

BTW, don't know if this would work for you, but I did find a local bike shop, one that works on old bikes, that sold me individual shims. All I had to do was take one of my own shims to the shop to match the diameters.

They charged me $6 each.