Shims for valve ajustment

[Brendan W]

Bear in mind that when Steve says take inventory of your shims do not rely on the thickness on the shim. It may have been ground before. You might spot tell tale marks depending of how good or bad the grinder did the job. It's good practice to verify with a vernier caliper.

 

[Steve]

True enough, but hopefully, if the person that did the grinding was concientious enough to grind on the side with the printed numbers, you would HAVE to measure the shim to know the thickness.

Fortunately, not many people have access to proper grinding machines, so this is a rather rare situation.

.

 

[chuck hahn]

I measure every one regardless. That may be just me. I wipe them real dry before measuring too...oil adds thickness

 

[Brendan W]

I measure every one regardless. That may be just me. I wipe them real dry before measuring too...oil adds thickness

I should hope so otherwise we're wasting our time filling sumps
Seriously, it's no harm to get a reminder of what oil is expected to do.

 

[salty_monk]

GhostGS ground me some down to custom sizes to put them all on top tolerances in the skunk many moons ago...

 

[Brendan W]

About five of mine are at or close to the thinnest stock shim. Is there a red line for thickness and you go to the valves?

 

[Steve]

If you have that many that are approaching the minimum, you might want to step back and evaluate the rest of the engine. :-k

The way to fix that would be to remove 0.5 to 0.7mm from the tip of the valve. That would require shims that much thicker.

While you have the head off to remove the valves for their shave job, you should also install new seals.

How are the rings? Any other gaskets leaking that would be easier to change while the engine is apart?

.

 

[Brendan W]

The engine is tired. The 53k on the odo is optimistic I'd say judging by the state of the cam chain runners. I did a top end gasket and seal job in 2014 with a ?70 complete engine set. I was losing a liter per 400 miles at the time through the front of the headgasket. Bores were good. I have engine oil leaking into the intermediate transmission space as well. Cosmetically the bike is not the best and an unlikely candidate for a full restore.Seat pan is cracked headers getting rusty. It keeps soldiering on. It's been down hard on the right. There is a brake pedal gouge in the clutch case and it has a round master for the front brake and the turn signals are the later plastic type and the engine mount plates are stainless steel. Bit of a Frankenbike and probably going for parts if or when I ever replace it. Still starts on the button and with two up it just pours on the torque in top gear at silly low speeds.

 

[Chuck78]

About five of mine are at or close to the thinnest stock shim. Is there a red line for thickness and you go to the valves?

Time for a machine shop valve job and evaluation of the valve faces. When they are worn that much that you are at the thinnest shims, the valve faces are very worn and eroded, and your head will be flowing in a sub par manner.

 

[Brendan W]

Time for a machine shop valve job and evaluation of the valve faces. When they are worn that much that you are at the thinnest shims, the valve faces are very worn and eroded, and your head will be flowing in a sub par manner.

Seems like some one tried to do a lot with the motor. When the head was off the valves seats seemed too clean like a recent job. Maybe they went too deep or had to.

 

[Forden]

First check your clearances and verify what?s you have in the bike THEN order them if necessary. Depending on what is needed you may be able to move a few around and reduce the cost. However, DO NOT TURN THE MOTOR WITHOUT A SHIM IN EVERY LOCATION.

The Shim Club thread is here under GS Parts and Services: https://www.thegsresources.com/_forum/showthread.php?122394-GS-Valve-Shim-Club

Well, I am that STUPID guy who did turn the motor with one shim out before I saw this. From what I can tell it scratched off a bit of the cam edge, and I *think I got out what little metal shaved off. Do I need to be concerned beyond that?

Sometimes learning is painful...

 

[Grimly]

I've never done that.
Nope.
Never.
And even if it happened, I'd deny it.
Honest.

Don't worry about the edge being slightly bothered, they'll run for many thousands and thousands of miles in that state, almost as if it didn't matter.
Some say that a coin is an adequate substitute for a shim if you have to turn the engine over with a shim or two (or several ) out, while you figure out what ones you need to swap or get new. It's true.