My valve clearance is... TIGHT? And other Q's [W/ PICS]

After struggling for ages trying to get the carbs to sync properly with no luck, I finally decided to check my valve clearances. I read up on Bigfitz's write up on how to go about checking them, and from how well it was explained, it was pretty easy to grasp the concept.

Well, The valve cover came off with ease and I only had to use the impact driver on the crank cover plate. But once I got down to the actual checking of the clearances things got weird.

Manufacturers spec for valve clearances were [.11-.15 mm] for the intake, and [.16-.20 mm] for the exhaust. But I bought the wrong feeler gauge I guess because the smallest feeler it had was [.127 mm]. I decided to proceed anyway, and got these results.

INTAKE:
Cylinder #1: [<.127 mm]
Cylinder #2: [<.127 mm]
Cylinder #3: [<.127 mm]
Cylinder #4: [<.127 mm]

EXHAUST:
Cylinder #1: [.152 mm]
Cylinder #2: [.178 mm]
Cylinder #3: [.178 mm]
Cylinder #4: [.152 mm]


Intake on Cylinder #1. But I Couldn't fit the thick bitch in there.


Looks like its perpendicular to the valve... right?


So, not a single valve was even near loose, and the exhaust valve on #1 and #4 were [.008 mm] too tight. I couldn't get the smallest feeler gauge into any of the intakes, so its somewhere below [.127 mm].

I really don't want to have to replace any shims that I don't have to, and I unfortunately don't have the special tool that Bigfitz has to pop 'em, which makes me even more not want to replace any.

So, my question is... Is the [.008 mm] too tight on the exhaust valves going to seriously affect anything? And wouldn't it be a good thing if the clearances were just a bit tight? If they loosen over time does this mean somebody has been in here replacing shims not that long ago? And, according to my pictures, I am doing this right... Right?

All advice appreciated.

-KJ

 

They don't loosen over time, they tighten, and it is important that they be in spec. Your best bet is to get a feeler gauge that goes small enough, and you will want to replace the shims (which are cheap). There are other options than the tool, although the tool does work quite conveniently.

 

I was afraid of that... Is the .008 gonna make a huge difference though?

Also... Check out those gnarly scratches on the tip of the cam lobe in my second pic. Something I should be worried about?

 

KJJohnson447, that does look perpendicular to me. I always center the top of the cam lobe - straight across from the cam bolt like in that pic.

I also have those scratches on the cam side, so it might be normal?

 

YES, running exhaust valves at half their recommended clearance will "make a difference!" You trying to burn a valve or four?

They tighten, not loosen. You need to get those in spec right away.

Here's the piece on the alternative to the tool: http://xjbikes.com/Forums/viewtopic/t=29209.html

The grind marks on the side of the lobe are fine. Yamaha never used much "finesse" on the cams except where absolutely necessary.

 

Get those valves in spec! You said your self you've been struggling with the tuning. getting thinner shims will loosen the valves to where they should be and you'll notice a difference. I just went through the same ordeal to fix my tight valves. Its made a noticeable difference.

I'd also pick up some feelers to properly check the intake valves. As you know they're not too loose; you're unaware if they're too tight.

6 of my 8 valves were out of spec. I also lucked out that I was able to swap some valve shims around and only needed to buy 4. Do yourself and the bike a favor and put the time/money into getting those valves in spec! You'll both be happy with the results!

 

You need to buy or borrow the right gauges to measure accurately the clearance of your intake valves. The only thing we know for the moment is that they are all tighter than 0.127 mm.

 

im going to get flamed for this. but in the interest of saving money and time. In a pinch i have ground down the backside of the shim to get proper clearance. Carefully measuring the shim before and after, to ensure a uniform thickness, then measuring it again once installed on the bike to verify clearance.
Seemed to work well.
Flame away.

 

Well, I hope your caliper is more accurate than your feeler gauges...

 

Shims aren't harden through the whole shim. Grinding the shims makes them weak, I'd never recommend for someone to do that. Short cuts like that to save money only cost more time and money in the end.

 

Listen to Steber and Fitz! I did and ordered everything up and plan on doing it this weekend!

Oh, and my feeler gauges, recommended by Fitz, go from .01 - .10, but then jumps to .15... metric...

Is that jump from .10-.15 gonna screw me up?

Jim

 

You can use two feeler gauges to make up the difference, i.e 0.10 + 0.1 to make 0.11.

 

Are you sure you don't have a 0.127 feeler stuck to the adjacent ones, they are pretty thin, obviously ... ?

 

Good call. Looks like it actually starts at .4.... but yea, I can just double some up, never thought of that

 

If you double gauges, just make sure you wipe the oil off of them. The oil film has its own thickness and will foul the measurement a bit..

 

I could see if you ground the side that the cam rides on/against. but i had done it to the underside. It is always in contact with the bucket (or whatever it is called that is above the valve spring/retainer)
If it was ground to the side that the cam rides on, i could see it wearing down the shim but its to the underside.

And yes the shims are only hardened on the outside. However the reason why they are hardened is to protect against wear, not cracking due to weakness, correct?

 

Ahh good call. How should these feel when measuring. They should go in snugly but not with a lot of force?

 

Case hardening acts to (can you guess it?) harden the exterior of the shim. This makes the bearing surface stronger and more resistant to wear, yes, however the harder a material is, the more brittle it is and therefore is more susceptible to cracking.

By altering the top or bottom surface you have removed the uniform characteristics of the hardened exterior. While this may not seem like an issue for the side of the shim resting on the bucket, the vibration and shock that the shim receives from the cam contacting it propagates throughout the material so by weakening any area of the shim's surface you can induce catastrophic failure (cracking) much quicker than if the surface was left unmolested.

I would not recommend doing this, although you can probably get away with it for a while. Shims are cheap enough to swap out and important enough to the successful operation of the engine that I would say its worth laying out the cash for what you know will be a good, strong and, most importantly, SAFE component. IMHO it's not worth saving a couple bucks now when it could lead to some major issues later.

 

Ok.

In the interest of saving time and money, rather than doing it right, I decided to wrap my brake lines with electrical tap, retread my tires with a soldering gun, duct taped my car battery to the side to increase my headlamp and put bubble wrap on my head rather than a helmet.

I'm not flaming you tho, just some absurdity to point out "where does it stop?". McGuiver is in the details. Your life, your money, your call. Personally I'd not trust my life and bike to him to save on an 8.95 shim, especially when you amortize them over the miles. Plus Hogfiddles has the Shim Swap which makes them even cheaper.

 

SHIMS ROTATE in the buckets; both sides need to retain their hardened finish.

 

Gotta get into spec .... fine tuning the carb just not possible without the valves in spec.

 

0.10 = 0.1 so 0.10 +0.1 makes 0.20 (or 0.2)

 

Not to mention the grinding marks on the shim rubbing against the lobe or bucket,The do rotate as they work do they not?

 

Glad I teach music........I only have to count to 4.

If I remember correctly, 0.10 + 0.01 = 0.11

Dave F

 

Funny Dave... Sometimes you need to count to 12... Blues!!! I IV V

Hey so i found a bottle of Permatex high tack gasket adhesive. The one used in Fitz's write up. It's about 2-3 years old and cap was on tight the whole time. You guys think it's still good? Seemed tacky enough to me but what do I know!

 

God, that Permatex has given me hell. I bought a jar of the stuff a few months back, and had it stored away in my tool box. Apparently it tipped over at some point, and the cap must have not been on tight enough, because next time I opened that drawer there was a quarter inch layer of the bastard on everything. I literally had to pry my tools out from the gunk.

As far as I've seen the permatex last a long time when being stored. I have seen no degrade in quality after even years of sitting. Just as long as its closed tight.

 

Another question for the forum:

I went to my local parts store looking to order a new valve cover gasket and doughnuts, but they could only find me a premium one ( 172 for the valve cover and 50 for the doughnuts) or some off brand for 60 bucks for the valve covert and 15 for the doughnuts.

Is it just me or does this seem ridiculously
over priced?

 

Ridiculously over priced.

Contact Len (Chacal) info@xj4ever. Guy is awesome! I just took delivery of the valve cover gasket, donuts, shim bucket tool, silicone grease, some other odds and ends for $106.

And he knows EVERYTHING about our bikes

EDIT: The 60 + 15 isn't too bad. I'd still go with Len on this. That's something you want to make sure fits like it should.

 

I thought they were. Ill have to talk to chacal about it then.

Say, what is the smallest feeler that yall have on your gauge? I bought a twelve dollar craftsman one, and im surprised it doesn't have the thin feeler than I need.

Any recommendations on a good cheap one that will have what I need?

 

Haha, dang, yes you're right, and the lesson learned here is to proof read before hitting submit.

What I meant was 0.1 + 0.01 = 0.11

But I guess everyone figured that out by now.