Help Valve clearence?

[Marine36]

I decided to check the valve clearance. The smallest feeler guage I have is .0015 in. I could not get this between any lobe or shim. Did I do something wrong? I understand these clearances get tighter with age. How is that possible? I figured they would wear and get bigger. HELP

[tkent02]

I decided to check the valve clearance. The smallest feeler guage I have is .0015 in. I could not get this between any lobe or shim. Did I do something wrong? I understand these clearances get tighter with age. How is that possible? I figured they would wear and get bigger. HELP

They get tighter, the valves generally recede into the seats, so the valve stems seem to get longer.
If no feeler gauges fit, spin the lifter bucket by hand with the cam lobe up, if it won't spin freely you have zero clearance, damage is probably being done when the engine runs. If it still spins you have at least a tiny bit of clearance, you may have lucked out and caught it in time.

[bwringer]

You have to remove the shim and insert the next size down until you get some clearance.

Sometimes you have to jump two or three sizes if it's been badly neglected.

And please, get a metric set of feeler gauges. It's much easier to keep straight in your head if everything is in millimeters. $5 at any auto parts store.

[Marine36]

Could not find a metric set of feeler guages? Checked Autozone and OReileys.
Believe me I would have prefered it.

[BassCliff]

Hi Mr. Marine36,

What bike are we talking about? Is it an 8-valve or 16-valve motor? Either way, try your best to find a metric feeler gauge set. Autozone should at least be able to order one for you. Check my website for valve adjustment guides. They've got lots of pictures and information. I hope you find them helpful.

If you have an 8-valve motor, send Mr. Steve an email requesting his handy-dandy valve adjustment spreadsheet. It will help you keep track of what you have, what you need, and what you've done.


Thank you for your indulgence,

BassCliff

[Marine36]

I have an 1983 GS1100G. I have been on your sight religiously, it contains great info. I tried the zip tie trick to lock open the valve I failed. Will try and get shim tool order later.

[chef1366]

My feeler guages have in and mm on them.

[Marine36]

Shims do move freely with lobes up.

[tkent02]

Shims do move freely with lobes up.

Good, you are not that far off.

[chef1366]

I have an 1983 GS1100G. I have been on your sight religiously, it contains great info. I tried the zip tie trick to lock open the valve I failed. Will try and get shim tool order later.

Did you fold the zip tie in half and stick it in the valve from the spark plug hole and rotate the motor until the valves close. The zip tie will keep the valve from closing all the way to create extra clearance to remove the shim.

[Marine36]

I will try again later. Its past my bedtime. Thanks to all for the help. One last question. Since my valvel were so tight, how do I know if I did any damage?

Thanks again.

[chef1366]

You would burn valves and your compression would be compromised.

[CCMcC]

Tips (such as they're worth) from a Valve Adjust Newbie

I'm working on my 8-valve 1982 GS850G and on my second (hopefully final) round of ordering shims.

Tools: The OEM tools are hideously expensive.

MotionPro has a tool for depressing the valve bucket to remove the shims. I ordered this aftermarket version of the shim tool ($18) and an aftermarket full metric set of feelers ($6) from a local YAM/SUZ/KAW dealer. Or you can Google "Suzuki GS Valve Shim Tool." The tools make this job much easier.

Shims: Some of my shims were worn and I couldn't read the numbers. I exchanged shims to get a reading. (But, be careful NOT to rotate the engine when you have a shim out). Re-install oiled shims number side down.

You may be able to move/reuse some of the existing shims.

I found it helpful to think of the shims as coming in half-sizes (2.55, 2.60, 2.65). If a 2.65 gives you too big a clearance (over .08 mm), try the next half-size down, 2.60. If you're under .08 mm, try the next half size up.

If a shim resists being pried out with a small screwdriver, I found that the point of a sharp pen knife was effective.

Use tweezers to remove the shims once they're dislodged. (Honey, why are my tweezers covered with engine oil???)

I also wasn't able to get the smallest feeler under the lobes on #4 cylinder. I am relieved to hear that free turning buckets (to get the notch where you can see it) is a hopeful sign. I went down 2 "half sizes" and the clearance in now spot on for #4.

I read that the way to know if you have valve damage is to use the proper tool to do a compression test (after you adjust the valves). If there is a low compression reading, add oil through the sparkplug hole. If the compression gets better, the rings are probably worn. If the compression does not get better, you probably have a burned valve.

For all practical purposes, if your bike is running OK and not burning oil after the valve adjustment, don't worry about it. That's my plan.

[Steve]

I decided to check the valve clearance. The smallest feeler guage I have is .0015 in. I could not get this between any lobe or shim. Did I do something wrong? I understand these clearances get tighter with age. How is that possible? I figured they would wear and get bigger. HELP

The smallest clearance that is specified is about .0012, so if your .0015 does not fit, you would just as well off to replace the shim. No, you probably did nothing wrong, that's just the way things go.

If you have an 8-valve motor, send Mr. Steve an email requesting his handy-dandy valve adjustment spreadsheet. It will help you keep track of what you have, what you need, and what you've done.

Thanks for the plug, BassCliff. I have been sending out several of these over the last few weeks.
Seems like more and more are doing something called "winter maintenance".
By the way, my spreadsheet can handle inch or metric measurements with equal ease.

My feeler guages have in and mm on them.

Chances are that they are actually inch feelers and have the metric approximations on them.

I found it helpful to think of the shims as coming in half-sizes (2.55, 2.60, 2.65). If a 2.65 gives you too big a clearance (over .08 mm), try the next half-size down, 2.60. If you're under .08 mm, try the next half size up.

I don't really want to burst your bubble, there, but the intervals you mention are WHOLE sizes, not half sizes. The half-size shims are the "X" shims. Between the 2.55 and 2.60 would be a 2.55x. If, for example your clearance is at the minimum of .03mm (.0012in) and you have a 2.60 shim, changing that to a 2.55 shim will increase your clearance to the maximum specified clearance of .08mm (.003in). Going from one extreme of the tolerance to the other can not be construed as a "half" size.

Keeping your valves on the looser side of tolerance has a couple of benefits, too. Having more clearance on the intake valve closes it just a bit earlier, bringing the torque curve down a few rpm where most of us spend more of our time. It also has the possibility of extending adjustment intervals a bit. Checks should still be done, but you might not have to change anything. Even at or just above the max clearance, there is so little clearance that noise is not an issue. The engine makes so many other noises that you will never hear the difference between .08mm and .09mm on the valves.

.

[BassCliff]

...and for measuring those "half" sizes ("x" sizes), a digital caliper comes in very handy. A 6 inch model is all I use. This is about $16 from Harbor Freight.



When using the "x" sizes, you can really fine-tune your clearances. This tool also comes in handy when checking your carburetor float height, clutch plate thicknesses, etc.


Thank you for your indulgence,

BassCliff