81 GS 650L Poor performance/ gasket for cylinder head cover.

[steve4mc]

First of all, I've got several questions. My Bike's performance has been getting worse as time progresses for quite a while. It is to a point now that I cannot ride for very long without fouling the plugs particularly #2. Plus I miss that power I had when I bought the bike in 1984 from my Pop.

I took off the cylinder head cover (what I would call the cam cover) to check the adjustment on the valves. And I cannot find any way to do it. I was looking at my buddy's GS1000 book to see what the spec is on clearance and how often to check them. My bike looks totally different than the pictures in his book. I don't even have tappets. SO, can they be adjusted? What is the spec? Is it less than .008 (my smallest feeler gauge)?

One of my earlier attempts to improve the flagging performance was to replace the spark plug boots. I bought NGK aftermarket ones that are marked as 5K ohm. If that is different from OEM resistance, can that cause the poor performance in spark plug life?

One other thing that I did was change from the foam filter to a paper pleated air filter. If I did this and did not change the jets in the carb can I be running rich for that reason ? I've had the carbs off and cleaned everything I could get apart but did not replace any rubber components.
I've been reading the fouling threads in the forum but none has addressed these questions.

I did a compression test in the past and noticed lower than spec numbers but at that point it was not running this bad. That was my reason for looking at the valve adjustment.
Also, if the infamous O-rings are old and don't seal good anymore would that result in spark fouling? I would think it would tend in the other direction.

And, yes, I have ordered the right manual. It just isn't here yet. Thanks a boatload for any help!

Steve Myers

[gspaul]

Your valves are adjusted useing shims of a different thickness, my bet is they are to tight.
Clearance, .03-.08mm.If your lucky you may be able to swap them around to get the right gap.
Order the stock air filter, and wait until your manual gets there.
Do these things first ,and we go from there.
Hear from you soon!

Oh! and you need a new valve cover gasket, and the little haf moon rubber end caps( 4 of)

[steve4mc]

The valve cover gasket.

Yes, the gasket has been an all day deal to procure one. My dealer said they were discontinued and could not even give me a number. Bikebandit.com had them listed but with two different part numbers that corresponded to F no 104613- which took the customer help person about a half an hour to determine what that meant. He finally was able to decide it was the frame number (I'm sure hoping he is right). So, do you really think I need the little half-moon endcaps? I was hoping to reuse the old ones. Does the new gasket come with new ones? Maybe I should ask bikebandit but I don't want to waste another hour.

Thanks for the reply (I miss my ride terribly).
Steve Myers

[gspaul]

There's a good chance you can reuse your old half moon's, I have when I had to, clean them up really well and give them a light coat of silicon when you put it together.
The last valve cover gasket I used was made by ATHENA.
You can also get a reusable silicone gasket from realgasket.com,have a look see if they have your model.

[steve4mc]

Why the stock air filter?

Like the subject line says, why the stock air filter over the paper one? The foam one disintegrated in the Oklahoma heat and other influences. I would bite the bullet for a foam filter if I knew there was good reason. It won't be cheap because I have to buy the filter element and the little plastic cage it goes on.

[gspaul]

Once you have used a few paper filters, you have paid for the foam one that can be cleaned and reused for the next 20 year's.
I bought one last year for $38AU,that's about $29US.Mine was rotted as well,but I was also told it was the same one from new, that aint bad!
We don't know if this paper filter is more restrictive or not.
I never even knew they made a paper filter for this model!

[steve4mc]

fixing the valve clearance.

GSPaul:

You may be right. I don't know that the paper filter is for this model (I found it at the cycle salvage place several years ago) but it fits tight. In taking it out today and looking at it, I think it would be time for a new one. I can still see light through it but not much.

I did get a feeler gauge with small enough feelers to measure down to .002 and found that all the clearances are less than .002. So now what? Do I have to get different size shims and pull the cams? Do you have to experiment with sizes until you get the right clearance? As you can guess i'm still waiting on the book and getting impatient.

[gspaul]

Sound's like you may be up for some new shim's.
When you get the manual there will be a chart , the number's down the side are what every the gap is now, the number's at the top are the size of shim you have at the moment( the size is marked on the shim), this chart will tell you the size of shim you will need.
You will not no what you need until you have checked every valve,all the shim's in there could be different, so some you can mix and match.
No you do not have to take your cam's out, there is a special tool used to compress the spring so you can lift the shim out ,but I have never had one.
You can get by without it, if there's anything I have said that your not shure about it will be much clearer when you get the manual, pictures help.

[steve4mc]

What to shoot for as far as valve clearance?

Should I try to shim it toward the looser end of the scale since they are so tight now or should I just try for the min clearance so I get less valve noise?

I finally got my manual and have been reading the section on adjustment. Also read your response on another thread about the tappet tool. That helps as well. Guess I will dive in and try to remove the shims and see what they are. Right now the clearance is less than the .002 in feeler gauge so I cannot do any math to tell how much to reduce the shim thickness.

Can the feeler gauge be too wide to get the right measurement? I was wondering while I was trying to get it below the cam.

[gspaul]

I tend to aim for the looser end,.05-.08( sorry I only think metric )valves generaly got tighter with wear.
There's plenty of room for feeler gauges,you have got the width of the cam lobe.
Good luck!
Oh! and dont turn the cams over without a shim in there.

[steve4mc]

tool substitute

Paul:

If you did not use the suzuki tool to compress the valve springs to get the shim out, what did you use? There is not a lot to press against to compress the springs and I can't get any kind of purchase long enough to pull that shim out. Am I going to have to spring for the tool?? I'm frustrated.!

Can you tell anything about the clearance if the tappet is difficult to turn around? And does the lobe on the cam have to be opposite the shim to get an accurate reading on the clearance?

Oh, and thanks a ton for watching this post. You've been a lifesaver.

[gspaul]

I use a plastic coated nail/centre punch, it comes to a sharp point.
I rest the point on the edge of the bucket, and useing the camshaft as a fulcrum, lever the bucket down, which compresses the spring.
Would it be easyer to use the right tool? Yes of course it is,but I still get the job done in the same amount of time, so it dosent bother me.
There's a picture in your manual that will show you the correct position for the lobes.
To remove the shims I use a tiny screw driver to lever it up(there can be a bit of resistance because of oil between the shim & the bucket )
Then I use a pair of tweezers to pull them out.
If the cam lobe is in the right position and the bucket does not want to turn, or you can not get any feeler gauge in there, that mean's you have zero or negative clearance.
Of course your chart cant help you there can it!
So what you do is swap it with another one that is a bit smaller and then check your clearance so you can work out what shim to use.
These shims have the sizes stamped on them, when you put a shim in put that stamp face down, so the cam wont rub it off.
See how you go!

[gspaul]

Funny thing is, it all seem's quite hard at the moment, but when you have done it just once it's dead easy.
You will find the bigest pain in the butt is just taking of the tank and whatever just to get to them!
And if your valves are pretty tight now, once you have them adjusted properly you will find out just how quick these 650s can be.
Good luck!

[steve4mc]

New shims.

Allright. after much heartache, I got all of the shims out and checked their sizes. Most were 2,65 with one 2,70 and two 2,80. I put one of the 2.65 in the slot for the 2.70 and got a measurable gap at the loose end of the scale. What I take that to mean is that I need to replace the 2,65 ones with 2,60 ones. All of the intakes were the 2,65.

When I look them up in bikeband**.com there are two part numbers listed for 2.6. What's up with that? Which one should I get to get 2.60? Are there places to get them where I can pay less? Right now, it looks like I'm going to have to replace seven out of eight. I though about replacing just the intake ones and seeing how it runs. Also, can I machine down the ones I have, maybe on a lap grinding machine, or a machinist flat with some emery cloth? I bet the flatness spec on these babies is pretty tight.

My dealer tends toward the high side on parts but at least I don't pay shipping.

[gspaul]

No I dont believe they can be machined, you can also get shims from a bike wreckers( dismantlers? )but they MUST be Suzuki, Kawasaki look the same but are .5mm smaller.
I got a bag full of ebay for about $20.
I have never dealt with bike bandit, but my guess is one of those part numbers could be a "fat " shim normally marked with an X, so it would be just a tiny bit thicker.
Really as you have everything apart, it would pay to get them all right.
Sound's like you know what your doing now, well done!