AIRHEAD VALVE ADJUSTMENT with Pics

One question, How do the valves get tighter over time? I know they do,,, but how? I am no vulcan, but this doe not seam logical.

 

The relatively huge shim-and-bucket actuating mechanism doesn't wear appreciably; what DOES happen is the valves pound themselves into their seats, as both the valve seat and the valve itself wear.

As the valve pounds into the seat, the clearance at the top decreases.

 

I love this write up. It will really help alot when I do my first valve check. Now for the noob question. Am I correct in stating that the exhaust valves are the ones closest to the headers? I want to make sure so I really don't screw up my readings. Thanks

 

Yes. The exhaust is closest to the headers, and the inlet is on the airbox side. I used this same write-up when I did my adjustment. If it were not for this write-up I probably would not have been able to do mine by myself.

 

Fitz, your directions BEAT the clymer by 110% at worst. Will you be my friend? Haha.

 

Got a question for anyone listening.

I measured the clearances over the weekend. Pretty much everything's a little tight (.102mm), so lots of replacement shims coming up. But there were two valves (one intake, one exhaust) that I couldn't fit even the smallest gauge under (.0015"). I swapped that shim with another, rotated the engine a couple times, and tried again: still no room. What would you suggest I do here? Do I order a tiny shim and measure using that, or is there a way that doesn't require my placing two separate orders?

Oh, btw, great guide Fitz.

 

What sizes are in there now?

I would install a shim two or three sizes smaller and measure from that.

I have a small collection of used shims I have loaned out in the past to others who have had this problem; depending on what's in there (and what I still have) I could send you a couple to try.

 

The shim originally in there was 285 (I think, very hard to read). I tried replacing it with a 275, to no avail. I'll order some extra, smaller shims when I replace all the other out-of-spec shims. Thanks for the offer though, Fitz.

 

Even if the Numbers are impossible to read, ... Just Measure the thickness of the Shim with a Micrometer.

When you have No Clearance to calculate from, ... Borrow a Shim from another Valve and use the Borrowed Shim to give you a measurement or solution.

You could get lucky and borrow the right Shim and get the right Clearance.
You might not be lucky and have it out of specs.
Use the Value of the Borrowed Shim to give you a baseline to work from.

 

quick question:

does anyone recommend loctite or never-seize for the reinstall? i'm guessing i don't want either on the valve cover screws - don't want any of that stuff coming off the screws and finding it's way into places it shouldn't be - but what about the left side cover?

part of me thinks loctite - don't want those screws to work their way out, but i'm afraid i'll end up ruining the screw if and when i ever want to pull them out again - which leads me to think never-seize, but then i'll have to worry about those screws coming loose and falling out, which brings me back to loctite . . .

any thoughts?

 

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?

 

A Magnificent "Do-it-Yourselfer" ... Gloriously Illustrated with magnificent photographs.

 

How do you get the rubber washers out of the valve cover bolt?

 

It's a pain, but you should be able to just cut the old rubber section off, leaving the metal top. Then you should be able to muscle them off... I used an exacto knife...

 

I cut the whole works using a heavy wire cutters, then twisted them off.

 

+1. Just CHOMP thru them with a big pair of diagonals and twist the remnants off.

 

:wink: does anyone know the specs for the 400..would i be following the same steps only for 4 cams instead of 8....i don't have a manual and i can't find one anywhere! it's been driving me crazy try'n to get one...i'm still far from doing this to my bike..but just needed a heads up..what i need to pick up for this uber fun job... :wink:

 

If you're talking about the DOHC 400cc twin YICS "half an XJ motor" then you are in luck.

Except for actually accessing the valves, everything else is the same, just half as much work.

I have a copy of the "multilanguage" (yes includes English) service manual for the XS400 "Seca" but mechanically the XS400 Maxim is the same. The problem is, it's 71MB compressed. PM me with your email address and we'll see what we can figure out; maybe FTP or I can burn and mail you a CD.

 

Perfect guys,

Thanks a ton. I think I know what I am doing now.

Dave...

 

Dear BigFitz52, I am 56, this 1993 XJ 400 is the 21st bike I own, and will hopefully be the first one I will do the mechanical job myself.
The upper part of my engine is sounding really clunky, so I intend to begin checking the command chain. your tutorial on valve adjustment is wonderful . At a certain point you mention "a tool" that must be screwed to the head, supporting the cam shaft:

"Place the "tool" in position, ..."

Is this a specialized tool that is sold... where?

Finally, I wonder if there is a similar tutorial to check and replace the command chain?
Thanks, Aharon

 

Do you have a 4-cylinder 400?

If so it is very similar to the 550s. Your camchain tensioner is an assembly that sticks out the back of the cylinders, in the center below the carbs.

If it is the manual-type adjuster there is a locknut and bolt on the right side of it. It looks like this-- All you actually see is the body and the adjusting bolt if it's that style, everything else is inside. (Ignore the arrow in the pic, that was for something else.)



Adjustment is as follows: Remove the ignition cover as shown in this thread; and position the pointer to the "C" position on the plate.

Using a 12mm deepwell socket, loosen the locknut on the adjuster bolt. Then using a 10mm socket, loosen a couple of turns but do not remove the adjuster locking bolt. When you loosen the bolt you will probably hear a "click" as the adjuster takes up slack. You may not, no worries. Re-tighten the bolt to 6 newton-meters (51.6 in/lb) then torque the locknut to 9 newton-meters (78 in/lb) and you're done.

If you DON'T have a bolt with a locknut on the side of your adjuster then it is the "semi-automtic" type and I'm not 100% sure on that procedure as all my XJs have the manual tensioners.

The "tool" is Yamaha special tool #90890-01245-00, commonly known as the "Yamaha valve shim tool." It's readily available from almost any aftermarket motorcycle parts supplier like Bike Bandit, you can find them on Amazon http://www.amazon.com/VALVE-SHIM-TOOL-Y ... B000UKIT8U and XJ4Ever (link on the banner in the upper right) carries them as well.

You can also use a piece of #12 insulated electrical (house) wire with a hook on the end, shove it down the plug hole and hook under the edge of the valve to keep it open. I personally do not use or advocate this method.

 

Thank you bigFitz! As you can see, I have found my way through the "search by author" resource.
Yes, it's a 4-cylinder 400, black and beautiful.
Your advices are great. My bike's tensioner is like the one in the photo. I left all my tools in Brazil (why lug so much iron anyway...), so I will buy new ones here and begin filling my nails with grease - gotta love that!!
Great hint about "the tool"! I believe I will find it in Tel Aviv.
Aharon

 

i was thinking of trying to do a valve job on my 81 650 maxim, but i was wondering where you got that "tool" that you bolted on that you used in your pics
thank you

 

i was thinking of trying to do a valve job on my 81 650 maxim, but i was wondering where you got that "tool" that you bolted on that you used in your pics
thank you

 

Mike: First off, that's not a "valve job." A "valve job" involves pulling the head and renewing the valves (replacing or lapping) and valve stem seals, etc. A real teardown.

We're talking about a simple valve adjustment. A maintenance procedure.

The "tool" is commonly available from almost any motorcycle accessory shop, online, Amazon.com, and chacal (XJ4Ever, see link in banner at the top of this page or http://xjbikes.com/Forums/viewtopic/t=14561.html ) also carries them.

DO NOT pay $75.00 for one, they go for around $20 or less. (I saw one online the other day for $74.99!!!!)

Scroll up about three posts in this very thread and I posted a link to a pic of one.

 

Very nice write-up! This job is on my list for winter-time projects on both XJ bikes. (You wouldn't happen to have a write-up done for checking valves on a KLR650? That's on the list, too.)

 

think I need some new shims?!
Intake: 0.076 0.051 0.051 0.051
Exhaust: 0.076 0.178 0.076 0.155

I couldn't believe how tight most of these were. seems like only 1 of the exhaust shims are okay right? (.178)

 

personly I think that tool is a waste of money I like the copper wire method and tiny flat tip screwdriver, tool slips off too easy however you decide to do it wear safety glasses

 

so i got my numbers! i simply used a wire method to keep the valve open and with a tweezers was able to eventually get the little boogers from underneath the camshaft. whew went ahead and discovered all eight shim sizes and will be replacing 7 of them.
Fitz, without this write up including pictures I would have never understood this. also, thanks for your second part demonstrating the wire method with an extra piston head. helped tremendously understanding!

 

bigfitz, thanks so much for this write down...
I'm working on the X model, but it helps me to understand a lot of the technique.. My only challenge will be to remove the cam's.... Wish me luck

 

I just did it with the tool and didn't have a single issue with it slipping off. As I was doing it, I was wondering how it was possible for it to not work 100% of the time.