Shim Help

[Guest]

I bought a 1982 GS650GL from a friend a while ago as my first motorcycle, and I've been trying to get it running properly. Right now, I've narrowed it down to the valve clearance. I checked all valve clearances, and they are all either too tight or touching. Tonight I took out all of the shims, rearranged them, and now I have one valve within tolerance (about 0.005in). The rest are too tight.

To be honest, I have no idea where to look for thinner shims and what thickness I even need. The ones I have are 29.5mm in diameter and between 2.60mm and 2.70mm thick, and as far as I can tell, I'll probably need them to be about 2.45-2.55mm.

I looked online, and I really don't feel like spending $120 on a whole set when I only need a few. Is this something I could look for in motorcycle shops or Suzuki dealerships?

 

[ratznfragn]

Z1 Enterprises . About 6 to 10 bucks each,available individually.

 

[Big T]

Many dealers carry them in stock. But, some think they're gold plated, for what they charge.
if you have a local dealer, get a 2.45 or so, and install it in each of the tight cylinders. Measure the gap and calculate which shim you'll need for each cylinder.

 

[Rich82GS750TZ]

You may know this already, but reminders never hurt. Do not turn the crank on an empty bucket. You could damage the cam lobe or bucket lip. Put a quarter in there if you have to.

 

[tom203]

Best to have clearance at max or slightly above…..there are two different cam cover gaskets for the 650, so beware.
Read this link, especially regarding positioning of cam lobes…..an adjacent lobe wrongly positioned will influence the clearance reading.

http://members.dslextreme.com/users/bikecliff/images/gs850valve_adjust.pdf

 

[Gorminrider]

I hope you didn't take them all out at the same time!...take 'em out one by one and write their sizes AND the clearance measure for each in a chart with the date... You can then figure what shim is "needed" to make the gap right for each. You may then discover you can move shims from one to another to get the right clearance, thus "needing" fewer. Get the ones you think you will need before swapping*. (these are going to be thinner than most of the shims you have now) You'll only need to do this a major effort ONCE and then just update it as you go.

* Some (many, I'd hope) shops will exchange for a low cost as in: selling you the shims you need and giving you some money back when you return with the replaced shims...this obviously helps when you get the wrong ones to start. I keep at least one extra spare so I can try swapping before I look for new ones.

if you did take them all out at the same time, you can release the cam chain tension, loosen the cam clamps and put shims back in before wrecking things...this is even a method of changing several at once, but "one at a time" is easier to describe and the normal way.

 

[Guest]

I hope you didn't take them all out at the same time!...take 'em out one by one and write their sizes AND the clearance measure for each in a chart with the date... You can then figure what shim is "needed" to make the gap right for each. You may then discover you can move shims from one to another to get the right clearance, thus "needing" fewer. Get the ones you think you will need before swapping*. (these are going to be thinner than most of the shims you have now) You'll only need to do this a major effort ONCE and then just update it as you go.

* Some (many, I'd hope) shops will exchange for a low cost as in: selling you the shims you need and giving you some money back when you return with the replaced shims...this obviously helps when you get the wrong ones to start. I keep at least one extra spare so I can try swapping before I look for new ones.

if you did take them all out at the same time, you can release the cam chain tension, loosen the cam clamps and put shims back in before wrecking things...this is even a method of changing several at once, but "one at a time" is easier to describe and the normal way.

I took them all out and wrote down all of the clearences and sizes (didn't know you shouldn't have them all out at the same time tho :/ and most of the valves were actually touching) I rearranged a few but was only able to get one valve within tolerance. Since it's Sunday I have to wait for most shops to open on Monday so I'll call around then.

 

[Guest]

if you did take them all out at the same time, you can release the cam chain tension, loosen the cam clamps and put shims back in before wrecking things...this is even a method of changing several at once, but "one at a time" is easier to describe and the normal way.

I also agree with others on possible damage to the cams. I also agree that removing the cams WITHOUT MOVING THE CRANK is the way to fix this problem.

The only problem with that is that on a 650, you will need to remove the carbs to get the cam chain tensioner out, then back in.

 

[Gorminrider]

Yes-Good Point! it's a bear under there..Thanks for remembering for me! however!- If you turn the big knurled spring-loaded knob on the tensioner it releases the cam chain tension somewhat*...I won't say it's enough to lift one one end of each cam because i can't remember and I sold my 650 ..that's why I'd tell "someone" generally to just do valve adjustments one by one.

* "somewhat" depends on the flat part of the tensioner's plunger versus the lockscrew...and the slack the "flat part" unlocked can help depends on camchain wear ...once tension is released, the tensioner shaft's lock screw could be turned in against it to hold the shaft in place while cam is lifted...MORE slack could be obtained if the lockscrew is turned out to clear the flat spot's shoulders...but this is iffy- the shaft might turn, you'd lose the flatspot, and have to take the tensioner assembly(and the carbs) off to set it right again...

 

[Guest]

Hey everyone, thanks for the help, OP is my son and we've been battling this beast for a while. He found a local shop that did awesome working with him and trading shims out a couple times to get the clearances in spec. We now have 120+ compression on all 4 jugs, and at times we can get it to run. We think and have been told that the rings on left hand piston (#1 ?) may be stuck due to carbon build up from when the valve clearances were off. Its a bit smokey out that left tailpipe and that exhaust pipe doesn't get hot like the others do. The plug is wet when we pull it, and has spark when grounded to the engine. But that cylinder just won't fire. We have been told that doing the valve adjustment can throw the carbs way off, so he pulled them (again, he's getting good at it) and did a basic clean out without breaking the rack apart. We will be checking float hieghts and he shot carb cleaner through every orifice he could see. They look super clean, nothing obvious.

I've been looking for a bench sync guide for the 650, but there isn't anything I could find, unless I missed something on BikeCliffs awesome website. We have vaccum gauges for the final sync, but want to make sure we get them close on the bench before mounting them up again. for my CB550F, they say to get the slides to fit a 1/8 drill bit under them, and that's about right, but those aren't CV carbs, so not sure how to do that with these. Is there supposed to be space around the throttle plates for air to flow? RIght now they sit 100% closed, no gap at all. I do have the 300+ page service manual, but would be nice to have a step by step for the laymans in my garage to follow Thanks again everyone, we are taking one more shot at it this weekend before he was hoping to take it to college in Iowa on monday. We will see how it goes! IF anything its been fun hanging in the garage with him. We are both learning a LOT.