I just removed all the shims from 1979 GS 1000

[jknappsax]

I pulled them all to see what sizes I have, and can swap around to get some of the clearances right before I start the quest for other sizes to bring all the clearances into spec. I was wondering if I can still safely turn the engine over by hand with all the shims out. I didn't see any warnings in the factory service manual or the Haynes I have for this bike. I don't want to damage the cams. Any opinions?

[lurch12_2000]

I pulled them all to see what sizes I have, and can swap around to get some of the clearances right before I start the quest for other sizes to bring all the clearances into spec. I was wondering if I can still safely turn the engine over by hand with all the shims out. I didn't see any warnings in the factory service manual or the Haynes I have for this bike. I don't want to damage the cams. Any opinions?

Are you saying they are all out right now? Too late to ask if you already turned it a few times to get all the shims out. You probably shouldn't have done it this way if you did. Did you write down which shims come out of where? I suppose you run the risk of some scratching of the cam lobes if they hit against the bucket edges. I never did it that way and can't tell you for sure of potential problems. If you use 2 zip ties you can carefully shuffle 2 shims at a time.

[Dogma]

I was just thinking about doing this tonight, because I'm in the exact same boat. I just had the idea to use some zip ties to protect the cams from the empty buckets. I think I can close them loosely over the cam so I can turn the crank as many times as I need to (and cut them off without nicking the cam). I'll just have to make sure they don't fall out of position as the lobes come around.

I plan to do this as a precaution, even though I doubt the buckets are rough enough to damage the cam on just a few passes. I suppose I should make sure they're clean so they don't drag any debris around the cam either.


These zip ties are coming in very handy lately. I wonder if I can use them to seal the air box...

[lurch12_2000]

I was just thinking about doing this tonight, because I'm in the exact same boat. I just had the idea to use some zip ties to protect the cams from the empty buckets. I think I can close them loosely over the cam so I can turn the crank as many times as I need to (and cut them off without nicking the cam). I'll just have to make sure they don't fall out of position as the lobes come around.

I plan to do this as a precaution, even though I doubt the buckets are rough enough to damage the cam on just a few passes. I suppose I should make sure they're clean so they don't drag any debris around the cam either.


These zip ties are coming in very handy lately. I wonder if I can use them to seal the air box...

Not sure you're using the zip ties as I was referring to. I fold them over and insert them through the spark plug hole (plugs should already be removed so you can turn the engine). When turning the cam and see the valve open in the cylinder is when I insert to hold the valve open. Do a search on zip tie in this forum and you should see the thread that gives pics and describes the procedure before you do it!

[BlackStar]

Don't do it. The edge of the lobe will catch on the lip of the tappet and lock up the motor. Don't force it. Ask me how I know, at least I didn't force it!!!

[Dogma]

Don't do it. The edge of the lobe will catch on the lip of the tappet and lock up the motor. Don't force it. Ask me how I know, at least I didn't force it!!!

You were too late. Basically, you need a really fat zip tie or something that can hold the valve completely open. Otherwise, the corner of the lobe contacts the edge of the tappet as you describe. But it doesn't lock up the motor. I felt no extra resistance as I turned the crank, but I heard it.

So, I get to clean up a minor mess. I now need to deburr the inner edge of the tappet cover where the cam lobe made a pair of notches. I may need to lift the cam to make sure I do a good job. The shim went back in OK, I just need to make sure everything is clean and no chips are going to fall off. Unfortunately, the same goes for the cam. The cam lobe now has a .025" or so chamfer where it used to be sharp. I can feel with my fingernail a slight raised edge on the cam face where this happened, so I need to get a nice fine flat stone and dress everything up. I'll still have about 95-97% of the cam face un-screwed up, so I don't think I killed it.

In the mean time, I've given up trying to swap the shims around without extras. I'll just have to suck it up and take my best guess at which shims I'll need, and order a few extra sizes for the 3 valves that currently have no clearance. The shims aren't that expensive, and I'll need them someday anyhow.

[catbed]

i have shaved the corners off of three cam lobes. the first is when my zip ties fell out and the valve closed. and i had to turn it to get the lobe out of the way. the second time i shaved two because i tried to roll the bike backward in gear and the clutch was sticking. i had the clutch in of course. its not a pleasant feeling. just make sure you stone the lobes to get the burrs off.(if you happen to shave them)

[srsupertrap]

Real bad idea turning over the GS motor with out the shims installed because the force of opening the valves will be solely concentrated on the outside edges of the cam & tappet resulting in stress concentration, which occur @ sharp corners. As already mentioned, this will chip the cam lobe at the edges as noted.

Second, the cam lobe manufacturers harden the cam surface or face by either nitriding or perhaps a case hardening process; these treatments impart a super hard although thin (.001's") surface layer on the face of the cam. If you have chipped the cam you will be left with a rough outside edge and IMHO you should ensure that cam surface transition is well rounded. If the cam surface is stoned you probably will alter the Rc hardness.

If you have to peform all that unnecessary work, at some point you have to ask yourself was that really a smart idea?

[drhach]

Don't just buy random shims. You'll be doing this forever if you do. Put the shims that you have already got, back in the engine. Obviously you don't remember where they came from. Write down the numbers before you put them back in and note which valve and cylinder you are putting them in to. Get out your feeler gauges and start measuring. If you're lucky, some of them will be in spec. You can start mixing and matching the rest to try toe get even closer. This will take a little while. But trust, me it will be cheaper and faster than the way you want to do it. If you insist on doing it your way, buy a kit from Z1 or somebody else. Do one valve at a time and keep good notes. If you don't already have one, buy a tappet compressor (valve shim changing tool) while you're at it. This will keep you fom further damaging your engine by using a pry bar to compress the tappets.

[jknappsax]

Actually, I DID write down all the shim thicknesses...

... and where they were, so I can replace the shims now, and still have a decent idea of what shims I need. Obviously, it was not a good idea to do the valves this way. Had I known before I started, I would not have done it this way. I could not find information to the contrary before I did it. I only see one very small scuff on the #1 intake cam lobe way over at the outer edge, which I will carefully dress with a very fine stone. I do have the Motion Pro tappet tool which I used when I measured all the clearances, which were ALL tight. I appreciate all the responses and advice.

[hikermikem]

To be on the safe side, it might be a good idea to poke around the inside and outside areas of each cam bucket with a magnetic tipped screwdriver (or similar tool) before you install the shims.

Those little oil "reservoirs" may contain metal shavings and/or small metal particles, resultant from the cam lobes scraping against the bucket ID when you rotated the engine to get at each shim.

Ask me how I know this - and yes, I removed quite a few metal shavings that were in the oil.

The good news is, you'll only make that mistake once!

Good luck

[jknappsax]

Cleaned up the cam edges

There were a couple lobes that had edge damage, which I cleaned up with a stone VERY CAREFULLY! I cleaned out each tappet bucket of chips, kept any of the stone from getting into the head, and got all the shims back in without any further damage. I also got the #1 cylinder exhaust and intake in spec, the #2 exhaust and intake in spec. I need to get the correct thickness shims to finish the job. Do you think the damaged spots on the cams, even though cleaned up and smooth (but still having several lobes with slightly beveled edges) will cause the cam lobes to be wiped out? I know I did something really dumb, but hopefully not fatal, to the cams. Opinions?

[Nessism]

I'd run it. Low spots are less of a concern than high spots. The 8 valve GS engines have a lot of cam contact area so you most likely will be okay.

Good luck.

[jknappsax]

Run it it is!

I was hoping that I hadn't destroyed the cams, but the damage is minimal, and pretty well cleaned up, so here's crossing fingers. Thanks for the opinion.

[twistedwankel]

... and where they were, so I can replace the shims now, and still have a decent idea of what shims I need. Obviously, it was not a good idea to do the valves this way. Had I known before I started, I would not have done it this way. I could not find information to the contrary before I did it. I only see one very small scuff on the #1 intake cam lobe way over at the outer edge, which I will carefully dress with a very fine stone. I do have the Motion Pro tappet tool which I used when I measured all the clearances, which were ALL tight. I appreciate all the responses and advice.

All these headaches is why I bit the poison pill and took my old bike to a professional shop. Better for me to not have it for 2-3 weeks waiting for proper shims than to endure all these issues. I'm a better rider than a mechanic. 16 valves is suddenly too many to deal with. Besides I keep reading about people having trouble finding the right thickness shims. I can't imagine having to go thru this every 15k miles???? There must be an easier way??? So this must be why most new cruiser bikes seem to have only 2 cylinders now???

I salute your bravery in tackling such a recurring headache.\\/