Questions about shims

[skoolbustom]

Hey guys. I just recently got my bike (78 GS550EC) and i read on here that a valve adjustment needed to be done. I went out and bought my feeler gauge but the smallest size is 0.04mm and there wasnt enough space for it to fit. I did take out the shims 1 by 1 and recoreded the numbers and this is what i got...

#1 Exhaust = 2.75
#1 Intake = 2.80

#2 Exhaust = 2.75
#2 Intake = 2.80

#3 exhaust = 2.75
#3 Intake = 2.80

#4 Exhaust = 2.75
#4 Intake = 2.75

Now my question is what should i replace them with? the bike has about 16,000 miles on it and i dont think the po ever messed with it. the bike as far as i can tell is completely stock. I did swap one of the 2.80 shims for one of the 2.75's and the 0.04mm feeler did slide through but just barely. it wasnt very smooth at all.

should i change the ones at 2.80 down to 2.70 and the 2.75's down to 2.70? any help would be great. THANKS!

 

[BassCliff]

Hi,

Personally, if the .04mm feeler doesn't fit, I swap the shim. It's OK to run more on the loose end (up to 0.10mm) instead of on the tight end of spec. There is a valve adjustment guide on my website. Read the entire article as there is important information in the addendum. Do not turn your motor if there are any shims missing from their buckets.

The first time I performed a valve adjustment I had to go down two sizes on several shims. It's not unusual if the bike has been neglected. Send member Steve an email if you'd like a copy of his spreadsheet to help you calculate shim sizes and keep service records. There is also a valve shim worksheet on my website that you can download, print, and take to the garage with you for note taking.


Thank you for your indulgence,

BassCliff

 

[tkent02]

Try this:

Turn the engine until the cams are lined up as in the manual, try to spin the shim in the bucket with your finger.

If it will turn, there is at least some clearance, one size thinner should get you in the correct range. So if a 2.75 spins, go to 2.70.

If it won't spin, there is zero clearance, go two sizes thinner as a start. 2.75 won't spin, try a 2.65.

Of course you still want to recheck everything once the replacement shims are in place, but this should give you some idea of which shims you need.


Are you using the silly Zip-Tie method, or the rediculously awesome and professional tappet tool? =)

 

[Nessism]

Try this:

Turn the engine until the cams are lined up as in the manual, try to spin the shim in the bucket with your finger.

If it will turn, there is at least some clearance, one size thinner should get you in the correct range. So if a 2.75 spins, go to 2.70.

If it won't spin, there is zero clearance, go two sizes thinner as a start. 2.75 won't spin, try a 2.65.

Of course you still want to recheck everything once the replacement shims are in place, but this should give you some idea of which shims you need.

Great suggestion here! Tom wins the Tech Tip of day award.

 

[skoolbustom]

Thanks everyone. I'll definantly try that. I'll let you guys know the results in the morning.

 

[legaleli]

Thanks everyone. I'll definantly try that. I'll let you guys know the results in the morning.

I am going to use that rule as well!

 

[1_v8_merc]

Yeah, if 0.04 wont fit in there, i'd definitely change the shim out and just go down one size.

Cause if it ain't 0.04, it's either 0.03 or tighter.(see if the shim spins in the bucket with cam at proper angle)

If it's 0.03, that's the bare minimum allowed, which is too damn tight in my opinion anyways....

And if it's tighter than 0.03, you DEF need to change her out!

Some of mine were tighter than 0.03, so it's not super uncommon....but it's really not good for the motor....obviously.


Are you using the silly tappet tool, or the rediculously awesome and professional Zip-Tie method? =)

 

[skoolbustom]

Are you using the silly tappet tool, or the rediculously awesome and professional Zip-Tie method? =)

I am using the zip tie method. It was extremely easy.

 

[1_v8_merc]

I am using the zip tie method. It was extremely easy.

Yep,yep that's cool.

You wouldn't believe the looks I was getting from my mechanic brother and father and friends.....

Every single one of them was like "what the hell are you doing! You're going to damage the valves, you don't know what you're doing!!!"

I just smiled and said "First off, you don't even know what a shim/bucket system is....second, if it's so bad, how come hundreds or more people have done this method forever, and NEVER had a problem?"

Of course noone challenged me, they just walked off frustrated....

 

[Steve]

I have a "rediculously awesome and professional tappet tool", but it stays in the toolbox.

I really do prefer the "silly Zip-Tie method". :-\\\

Why? That's easy. I had the tool slip off the edge of the bucket before the shim was fully in place. Shattered the shim.

After about an hour of fishing with a magnet, then another hour of putting the pieces together, I was assured that I had virtually all the pieces. Anything that was not there was going to be too small to matter.

Unless there is some trick to keeping that tool in place, I will continue to use that "silly Zip-Tie method".

.

 

[Billyboy]

Hey guys. I just recently got my bike (78 GS550EC) and i read on here that a valve adjustment needed to be done. I went out and bought my feeler gauge but the smallest size is 0.04mm and there wasnt enough space for it to fit. I did take out the shims 1 by 1 and recoreded the numbers and this is what i got...

#1 Exhaust = 2.75
#1 Intake = 2.80

#2 Exhaust = 2.75
#2 Intake = 2.80

#3 exhaust = 2.75
#3 Intake = 2.80

#4 Exhaust = 2.75
#4 Intake = 2.75

Now my question is what should i replace them with? the bike has about 16,000 miles on it and i dont think the po ever messed with it. the bike as far as i can tell is completely stock. I did swap one of the 2.80 shims for one of the 2.75's and the 0.04mm feeler did slide through but just barely. it wasnt very smooth at all.

should i change the ones at 2.80 down to 2.70 and the 2.75's down to 2.70? any help would be great. THANKS!

The GREAT news it that you've got TONS of adjustment left.
2.75's! I wish!

 

[Guest]

I have a "rediculously awesome and professional tappet tool", but it stays in the toolbox.

I really do prefer the "silly Zip-Tie method". :-\\\

Why? That's easy. I had the tool slip off the edge of the bucket before the shim was fully in place. Shattered the shim.

After about an hour of fishing with a magnet, then another hour of putting the pieces together, I was assured that I had virtually all the pieces. Anything that was not there was going to be too small to matter.

Unless there is some trick to keeping that tool in place, I will continue to use that "silly Zip-Tie method".

.

I couldnt imagine any other mothod other than the ziptie thing.
Even easier with the motor removed.

 

[KDS111]

Please describe the zip tie method.

 

[Guest]

Please describe the zip tie method.

Stick a folded and taped ziptie into your spark plug holes to hold the valve open.
If your engine is removed you can even get to some of em from the exhaust holes
I wouldnt even know where or how to begin but I bet if ya do a search you'll find all the info you'll need.

Aint it on Cliffs site in detail?

 

[979roadrunner]

Yes, it is, and if Steve endorses it, I may leave my totaly awesome and professional tool in the box and try that instead.
I got my totaly awesom tool to lock in pretty good, but it did slip during instalation and removal (of the tool) the sacond time I used it (first time no drama, go figure) and even with the shim seated and safe, hearing it 'pop' caused a seat mohawk in my bike fixin' stool.

 

[Steve]

Here is what caused my "seat Mohawk":

I found the missing piece off the back side, just could not get it to stay with the rest of the shim long enough to tape it in.

.

 

[Truth]

Forgive my ignorance, but this is what happens to the shim when the tool slips?? I haven't taken this apart yet on my bike, and trying to get mental picture of what you're talking about.

 

[Steve]

That is but one possibility. If the shim is resting slightly lifted out of its spot in the bucket and the "special tool" slips out, the rapidly closing valve will press as much of the shim as it can into place. However, since some of it is supported on the raised edge, ...

.

 

[Guest]

That is but one possibility. If the shim is resting slightly lifted out of its spot in the bucket and the "special tool" slips out, the rapidly closing valve will press as much of the shim as it can into place. However, since some of it is supported on the raised edge, ...

.

Hey Steve, dont have to hold the valve open with the shim tool with one hand?(never used one)
I like to have both hands while working the shim into the bucket.

 

[979roadrunner]

If you get it locked into position right, you don't have to hold it, it'll stay locked in place.
Unless, apparently, it slips at an inoportune moment, as apparently has happened to more than one user on here.
Zip ties are cheaper, and if Steve say they work, I'd bet a hat they do, and from reading the tutorial, I don't see a downside, unless you're afraid your buddies'll razz ya for it.