Cafe Racer Forum banner

1 - 15 of 15 Posts

·
Registered
Joined
·
8 Posts
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!
 

·
Registered
Joined
·
2,347 Posts
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.
 

·
Registered
Joined
·
8 Posts
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
 

·
Registered
Joined
·
5,958 Posts
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:
 

·
Registered
Joined
·
84 Posts
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.
 

·
Registered
Joined
·
1,563 Posts
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.
 
  • Like
Reactions: woodsman and jcw

·
Registered
Joined
·
1,563 Posts
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
 

·
Registered
Joined
·
8 Posts
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
 

·
Registered
Joined
·
1,563 Posts
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.
 

·
Registered
Joined
·
1,563 Posts
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
 

·
Registered
Joined
·
8 Posts
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
 

·
Registered
Joined
·
2,347 Posts
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.
 

·
Registered
Joined
·
8 Posts
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?
 

·
Registered
Joined
·
1,563 Posts
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.
 

·
Registered
Joined
·
2,347 Posts
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.
 
1 - 15 of 15 Posts
Top