AIRHEAD VALVE ADJUSTMENT with Pics

Boys, I had a good afternoon!

Nice chilly day here in Kitchener, but thanks to this write up and a bit of courage I just managed to check the valve clearances on my 650 Maxim and boy i'm glad i did!!! They were all too tight, in fact the cylinder 3&4 intake wouldn't take a .04mm feeler gauge!!! exhaust were from .05mm to .10mm, and the loosest intake was .05mm!!! I really owe Fitz one or two or seven beers for this writeup, especially about using the impact wrench on the cover, some screws were worn down a bit by the PO and took a few whacks to loosen. Now all i need is the shim tool (anyone have one i could borrow??? ). Chacal, I suppose you'll be hearing from me in the near future, it looks like the valves were never checked and the gasket is pretty crispy.

For the record, I work in I.T. and have never performed any type of surgery on a engine, except for changing oil, plugs or air filters so if I can do it anyone can!

Mars.

 

I too need to thank you fitz, this write up is great. I checked my valves today (first timer) they were all to tight. I don't know what a guy would use if not a forceps, that is a genius idea! Works perfect getting them suckers out.

 

Thanks guys, I appreciate that.

mwhite74 I'll be making a run to Kitchener as soon as the weather finally gets nice, I may take you up on that.

If you've got a YICS bike, be sure to get a set of "donuts" to go with the gasket. "The Tool" is readily available for well under $20.

 

First off I'd like to thank Fitz as well as many of the other members on here that are so helpful in keeping our bikes in shape. That being said I could use a little more advice on my valve adjustment project I've currently undertaken. I noticed this year that I had some oil leaking out from between the cam end plugs and the valve cover on my 1981 XJ650H Maxim so I decided that I would replace the gasket and cam end plugs. Since I was going to take the cover off anyway I thought I'd check my clearances and I'm glad I did. The were all out of spec and looked as follows:
Ex. #1 0.15mm Ex. #2 0.15mm Ex. #3 0.15mm Ex. #4 0.15mm
In. #1 .06mm In. #2 0.10mm In. #3 0.06mm In. #4 0.10mm

The #1 and #3 Intakes have 285 shims in them and according to Fitz's chart I should replace them with 280's. Putting 280's in would put me at the minimal clearance of .11mm. Do you think I should put 275's in instead of the 280's?

Also, How do I replace the cam end plugs? Looks as though I just pull the old ones off but how should I re-seat the new ones? Gasket sealant? Grease? Oil? I'd rather it not leak again from the cam end plugs. Thanks for any advice you can give me.

 

Bring the loose ones back into Spec.
As long as you "Know" the Valve Clearances are at Minimum ... you are OK.
You'll Need to check them each Season.

End Plugs:
Even with End Plugs that are part of the Gasket ... I use an Age-Old Sealant the is tried and true.

Indian Head Gasket Shellac.

Use wire cutters and get rid of the HUGE Dabber that comes attached to the Bottle cap ( Unless you are going to do a whole Head Gasket).

Let a little bit drip on to a piece of cardboard.
Use a real small "Artist Brush" and "Paint" the Mating Surface of the End Cap and the Half-moon cut-out on the Head.

Let the Sealant get Tacky.
Fit the End Cap into the Cutout and adjust it with a straight edge.
Wipe-off and drip on the outside with a rag moist with Carb Cleaner.

 

Got all the shims out today and their values recorded. I guess i'm safe to assume that for the valves where i couldn't measure with even a .04mm feeler gauge (intake), i should be fine going 10 smaller on shim size to bring me into spec right? IE: Say a .03mm clearance, 280 shim means i can safely go to a 270 Shim to bring me to .13mm? At any rate I'm off to buy 8 shims, gasket and o-rings, wish me luck!

 

Your calculations and conclusions are correct!

 

Let me update my comment above..........actually, you should remove any shim where you can't measure clearance, and substitute a smaller size shim, and re-measure/re-calculate what the correct replacement shim should be. Better to take the extra time to do this procedure than to "guess" what you'll need, when you can't measure the clearance with the currently installed shim.....

Thanks to Wizard for catching my oversight and saving mwhite74 a possible further problem down the road!!!

 

Kitchener, eh? I'm in Guelph. Perhaps we could share tools (or I could buy/rent your "tool" tool!).

I'm currently fixing up my '83 550 Maxim and I'd like to to do this.

 

has anyone ever had any problems or concerns with changed or replaced shims seating correctly? i just measured and pulled all of my shims for the first time. when i replaced them it seemed like the shims didn't seat as low as they were when i pulled them.

i did try move some around to help get what i could in spec. so, some shims are different sizes than when i originally measured and some are the same. i tried to keep accurate records, but i think i got myself confused.

the shims that i pulled and replaced in their same spot seem tighter. however, my measurementss from before were huge (.381) yet now, since taken out and put back in, seem to be in spec (.127).

i seem to remember my feeler guage hitting the ring around the shim when measuring the first time. now my shims stick out above the ring.

what do you think?

 

Tap on the Shim with the Boxed-end of a Combination Wrench.
If the Shim ... "Tinks" it's not seated and you need to find-out why.

If the Shim IS seated it will ... "Dunk" ... a solid low note.

Some Shims ARE higher above the Bucket Rim.

 

thanks rick. i did try to tap on them, but it didn't seem to make a difference. would it be possible that they were seated too low to start with. do the valve shims themselves seat lower over time? they definitely do not seem to want to go any further down now.

 

No.
The Bucket has a Seat on which the Shim rests.
If the Shim is lying flat in the Bucket ... Rotate the Engine a few times, by hand, and let the Camshaft push the Valve Open and Closed a few times.

Get an accurate measurement after doing that.
If you are in Specs, ... that's good.

 

How difficult should it be to rotate the engine backwards? It turns forward fine, so using the bucket tool on the exhaust side is no problem so far. However, I really don't like the way it feels when I start to turn the motor backwards and I'm afraid I'm going to damage something.

 

You can rotate the motor backward but go easy, and be 100% sure you're not turning a cam against the tool.

What you're feeling is the primary chain take up tension the other way, and the starter clutch will usually engage so you will be turning the starter as well; just go slowly and steadily and not too far (you don't need to.)

You DO need to turn it backwards a few times during the adjustment procedure, but just go smoothly and slowly. You're spinning the alternator too, and you'll probably hear/feel that.

 

Great pics and guide!

So when I'm nearly ready to do this project I should:
A ) Order all the gaskets and boots and maybe the lifter tool
B ) Take it apart and figure out what shims I need
C ) Temp reassemble with new rubber/gaskets as desired
D ) Start over/finish after shims arrive

Sound about right?

 

Yes, and definitely the lifter tool, otherwise you can't figure out what shims you need (because you won't know what was installed).

Fitz, or anyone, question: I have one valve (exhaust #2) bucket that seems stuck. I can't rotate the bucket that holds the valve shim in place. The gap in the shim bucket is rotated to an inconvenient place (about 10:00 if noon is forward on the bike) and I can't get the shim out. I tried removing the cam cap, but still didn't have enough access. I even tried blowing compressed air into the gap in the shim bucket, which popped all the other shims out, but I'm not sure I really had a good line on this one and it didn't work.

I doubt there's an easy answer here. I'm at about 0.13mm so it's tight but not terribly so. The bucket and shim seem to move up and down just fine. The solution is probably to pull the cams/head and break down that valve, I guess. I wasn't looking for that much work! Has anyone else had this? Do you think there's much risk to driving it? I thought it would be a good addition to this thread.

 

chaz, even with the tool not installed and the cam lobe pointing straight up away from the shim/bucket, you can't rotate them around?

If the shim and bucket seem to be moving up and down OK you should be able to rotate them. What happens if you "hook" the notch and try a little gentle force? The bucket is just sitting on top of the valve, it's not held there by anything.

 

Correct Fitz. I tried pushing on it with an allen wrench end. Not too hard ("gentle force"), but I didn't want to gouge anything with a screwdriver. I guess I could apply stronger force.

If I were to remove the cam, could I lift the bucket off the valve stem and pull it out, check the seat for damage?

 

Sure. With the cam out, the buckets/shims can be lifted out. They just sit in there.

It's truly weird that it won't turn. When you rotate the engine over by hand, does it turn slightly (like the other 7) as the cam is pushing it down?