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Discussion Starter #1
Hey everyone, I'm working on the valves on my '79 GS750. Most are in spec but there are a couple in dire need of fixing. The manual shows that I need to use a "tappet depressor" to be able to pull the shims out but I can't find one of those in town and I don't wanna wait for one in the mail. Has anyone done this before with a screwdriver or something? Is it even something I can do without the depressor or is that tool an absolute necessity? Any advice helps, thanks!
 

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There's a trick where you stuff the cylinder with rope to hold the valve up...

But when I did the valves on my gs750, I ordered the tool and it made life really easy.

Did you download the chart off of thegsresources forum? It makes it easy to figure out where to swap shims around to get proper clearances; meaning you won't have to buy as many shims.
 

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Discussion Starter #3
There's a trick where you stuff the cylinder with rope to hold the valve up...

But when I did the valves on my gs750, I ordered the tool and it made life really easy.

Did you download the chart off of thegsresources forum? It makes it easy to figure out where to swap shims around to get proper clearances; meaning you won't have to buy as many shims.

Oh interesting... I have the service manual with the shim chart on it if that's what you're talking about. Are new shims easy to come by if I do need new ones? I've never seen these kinds of shims before
 

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Bucket and shim valve adjusters are very popular with motorcycle manufacturers because it is cheap and easy,
plus once it does wear out the whole valve train **its its pants.


I look at the special too in the service manuals and make something similar, but I'm big on bush fixes that save rude amounts of time and money.

do you have a micrometer and know how to use it?
do you have feeler gauges and know how to use them?



Ya it's raining, that will improve traction this weekend :cool:
 

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Bucket and shim valve adjusters are very popular with motorcycle manufacturers because it is cheap and easy,
plus once it does wear out the whole valve train **its its pants.


I look at the special too in the service manuals and make something similar, but I'm big on bush fixes that save rude amounts of time and money.

do you have a micrometer and know how to use it?
do you have feeler gauges and know how to use them?



Ya it's raining, that will improve traction this weekend :cool:
Here's a place where having the right tool is a must. You'll use it over and over, it's note very costly and if by not using it you slip and cause damage to other bits those bits will make the cost of the tool and the wait seem inconsequential.
 

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The zip tie method is easier and safer in my opinion than the motion pro depressor tool. The tool needs to catch the edge of the bucket so you can remove the shim. And it can easily slip. This can cause issues if the shim is partially out.

These engines are not interference fit, so you won’t cause an issue rolling the engine over with a valve partly open. Here’s the method:
1. Remove the spark plugs
2. Fold a zip tie in half and mash the fold flat in a vise or with vise grips
3. Roll the engine over by hand until the valve opens and you can see it in the plug hole
4. Insert the Folded zip tie in the spark plug hole between the valve and the head.
5. roll the engine over by hand until the valve closes on the zip tie.
6. The shim can be removed and swapped

One important thing to note. If you are removing multiple shims, don’t roll the engine over without a shim in place. The cam will gall the buckets. I use quarters as temporary shims and they work nicely. That way I can remove all 8 shims and swap some if I can. I keep $2 in quarters in my tool box drawer with my folded zip tie.
 
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Here’s a video, but this guy only removed one spark plug for the vid, so he has more trouble rolling the engine over than he should’ve
 

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Discussion Starter #8
The zip tie method is easier and safer in my opinion than the motion pro depressor tool. The tool needs to catch the edge of the bucket so you can remove the shim. And it can easily slip. This can cause issues if the shim is partially out.

These engines are not interference fit, so you won’t cause an issue rolling the engine over with a valve partly open. Here’s the method:
1. Remove the spark plugs
2. Fold a zip tie in half and mash the fold flat in a vise or with vise grips
3. Roll the engine over by hand until the valve opens and you can see it in the plug hole
4. Insert the Folded zip tie in the spark plug hole between the valve and the head.
5. roll the engine over by hand until the valve closes on the zip tie.
6. The shim can be removed and swapped

One important thing to note. If you are removing multiple shims, don’t roll the engine over without a shim in place. The cam will gall the buckets. I use quarters as temporary shims and they work nicely. That way I can remove all 8 shims and swap some if I can. I keep $2 in quarters in my tool box drawer with my folded zip tie.
Suuuper interesting. I'll definitely have to try it out. Also I couldn't find anywhere by me that sells the 27.5mm shims that my engine uses. Is there a website or somewhere I can buy a kit? All my exhaust valves have no gap and I'm not sure how to measure to figure out how much to take off without just going each size lower on shims
 

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Lash clearance on these is stupid tight.... like .001”-.003”(.03mm-.08mm). And the service interval is 3000 miles... so at each oil change. I’ve never bought a kit. I’ve always had good luck befriending a mechanic at a local shop who’s willing to swap out the shims I have for the ones I need.
 

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Use the quarters to get your measurements. Measure the thickness of the quarter and replace the shims with them temporarily. They’re thinner than the shims. You should have a gap that you can measure
 

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Discussion Starter #11
Use the quarters to get your measurements. Measure the thickness of the quarter and replace the shims with them temporarily. They’re thinner than the shims. You should have a gap that you can measure
Oh good idea. Thanks! Hopefully I'll get it all figured out tomorrow
 

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So I've seen conflicting reports on this (specifically when doing the shims on my suzuki vs my kawasaki)... but all the data regarding suzuki shim changes I've seen says to not use a magnet to remove the shim.

Conversely, I see a lot of guys in japan using magnets to remove the shims from their Z1's or KZ1000's.
 

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Discussion Starter #13
So I've seen conflicting reports on this (specifically when doing the shims on my suzuki vs my kawasaki)... but all the data regarding suzuki shim changes I've seen says to not use a magnet to remove the shim.

Conversely, I see a lot of guys in japan using magnets to remove the shims from their Z1's or KZ1000's.
What would using a magnet have anything to do with whether or not the shims would work?
 

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I just use a dental pick. There’s a slot on the bucket to get under the shim. And the zip tie method leaves both hands free to get the shim out. With the valve depressor, you have one hand holding down the valve and you only have one hand to get the shim out.
 

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What would using a magnet have anything to do with whether or not the shims would work?
As far as I remember, the intent is to avoid magnetizing the shims... I'll have to dig into it.

As 8ball mentioned, use a dental pick and some good tweezers to get them in/out. Also, keep in mind that removing them can be annoying due to the suction created by the tiny amount of oil around/underneath them. don't get discouraged.
 

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What ever tool you use have a good magent handy. I some time just put the magent on the tool. If you loose a clip in the engine you will need more tools. You may want to put some rags or paper towels in the open parts around everything.
 

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The Suzuki GS range have the easiest adjustment of any of 'The big four' with a tappet depressor that actually works.. It's possible to just pry the bucket down with a flat screwdriver and flip out the shim but never recommended as it's too easy to damage the bucket bore, usually have to remove head to fix it (and often need to replace broken valve guides where something stuck and piston hit valve)
Biggest issue with the GS range is the very tight tolerance they run, 0.00!" to 0.003" all round. I always used to set intakes at 0.002" and exhaust at the loose end of 0.003" (0.004" won;t go in) The exhaust valves do and will recede into head, tappets close up over time making bike very difficult or impossible to start when cold. If you keep riding with that problem it will burn out the exhaust valves.
Make sure you have the correct shims, they are easily available as the GS500 twin uses them and that was still in production until at least 2011 (may still be but I haven't checked)
The shims are different diameter to Yamaha or Kawasaki even though they look identical and will fit into bucket recess.
 

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Suzuki's are the easiest ones of all. Ducati's are easy enough when the heads are on the bench the way they were designed to be serviced. They are a fair bit more time consuming though 🕶
 
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