AIRHEAD VALVE ADJUSTMENT with Pics

I know the valve clearance is supposed to be checked every 5000 miles, but I'm wondering how long some of the valves have stayed within spec. Does anyone have any records to show valves have stayed in spec for 15 or 20,000?

 

Sort of.

I keep log books on all of my bikes; and I can tell you this: They do seem to "settle down" such that they don't get out of spec on every check, but they do change albeit slowly. I would say that "staying in spec" for 10,000 might happen; but generally not 15K or 20K.

You have to remember that "in spec" is a range and it depends on where "in the range" any particular valve was the last time it was checked.

If you check them every 5000 miles, you'll end up shimming maybe one or two, or maybe even none, depending on how close any particular valves were to being out of spec the previous time.

The key is to check them every 5000 miles.

carbonxe the "tool" doesn't work if it's not centered on the cam lobe; I covered this in detail in "Part 2" where I also explained the "zip tie trick." I never have a problem either, but I know the "secret."

 

Ive been looking for this post for hours!!!

 

BigFitz.... I love your write ups... I'm gonna have to do this

 

Thank you for this write up!!

I was intimidated by this job for a while whenever I saw it referenced in the forums. After reading this one, I went and bought some feeler gauges and did the measuring in decent time.

One confusion though, on my cyl #4, I took a measurement of .076mm for the intake. I popped out the shim, and it is a Y270. I look at the chart, and, em...? There is no suitable replacement?

EDIT: Nevermind... found my problem with numbers. (was looking for .7 instead of .07) Don't blame me, I was raised in the south! ;o

 

i cant seem to find feeler gauge with proper gauged fingers, does anyone know how much the intake and exhaust for all valves cost? think it be best to go ahead and place new one in and call it a day, oh and where can i get that valve compression tool that is shown in the pics.

 

Metric Feeler gauge: KD tools' 2274 http://www.google.com/products/catalog? ... DAQ8wIwBQ#

You can't buy shims until you measure the clearance, and if out of spec, see what is installed. There is no "standard" size shim, bikes straight from the factory have different thicknesses of shims on different valves.

I'll say it again: SLOW DOWN, go back and read this thread carefully it explains in detail exactly what to do and in what order. You can't "skip ahead." There are no shortcuts. You can't just buy a pile of shims, they come in like 15 different sizes.

 

Great post, thanks

Just a small note, that made me having a few sessions of bad words. Rotate bucket before placing tool, so shim can come out. Took me a few mins to figure that one out.

Maybe put that in there in the text on first page ?

 

What is the benefit of the valve adjustment?

 

Major benefit ! Probably the biggest 'must do' on these bikes. If your valves are out of adjustment, you could have loss of compression, valve damage and associated engine damage. It's an easy, routine maintenence 'must do' - just like changing the oil and filter. Doesn't take long to do and you don't need any specialized tools to do it.

 

mmmm Must do! I love to work on my bikes the problem is that I dont have a garage and sometimes....just sometimes is a real pain in the butt!!

Oh well! Gotta do it! Like is would say in spanish " Ni pedo " LOL

 

"Because you have to" isn't much of an explanation.

The valves are operated by the cams pushing on (shimmed) buckets that ride directly on the top of the valves themselves. As the valves "pound" themselves into their seats over time, the clearances in the valve-actuating mechanism tighten up. They can eventually tighten up to the point where a valve is not being allowed to close fully; at which point the damage begins.

Adjusting the valve clearances involves restoring the specified clearances between the various moving parts so that the valve train operates as designed.

This is equally important because the amount of time a valve spends open versus the amount of time it spends closed affects things like compression and manifold vacuum. Since the XJs are equipped with CV carbs, which are in effect vacuum operated, keeping the valves in spec greatly affects carb tuning as well.

 

I overshot the number on a shim I ordered, and now the exhaust clearance is 0.26mm, will it be a bad idea to run with this?

 

Not a good idea, that's for sure. Loose IS better than tight; too loose is risking spitting a shim. I wouldn't.

 

Here is my contribution to the cause.

It is useful!!

 

It is already in the article, too. About the 19th pic down from the beginning; and a tad easier to read. Thanks though...

 

That's right. I just put togeher the chart and on top there is aplace where you can take notes of your measurements.

Is there way to upload excel docs?

 

I just measured my clearances and got the following measurements:
Cylinder: 1 2 3 4
Exhaust: .006 .009 .007 .008
Intake: .006 .004 .006 .004

However, when I put my caliper on the feeler gauges they measure slightly bigger than they claim to be. The .004 measures at .0045, the .006 measures at .0065. This is important because depending on which measurement I go with determines which of the two intakes I need to swap out as well as determining whether I need to swap out #1 exhaust (.004' = .1016mm, not in spec, whereas .0045 = .1143, in spec; the problem is the opposite for the other two intakes which are in spec at .006 but not .0065).

So my two questions are as follows:
Which of these measures should I trust?
Are any of these so out of spec that they run the risk of damaging the engine if I continue to drive it for the next couple of weeks while I await my valve holder tool and then a couple more while I await the appropriate shims?

P.S1: I realize I need a set of metric feelers. I thought that is what I had bought since that is what they were advertised as. But like the feelers many of you are using, it is only a s***ty metric conversion feeler and the conversions are not very precise.

P.S.2: Sorry to drag up an old thread, but this is a good one that could always use a bump anyways.

 

Speaking as a machinist, calipers shouldn't be trusted closer than about a thou. If you really want to make sure the feelers are right check them with a micrometer.

I'm doing my 650, and got the following measurements:

Cylinder: 1 2 3 4
Exhaust: .005 .005 .007 .005
Intake: .0025 .004 .005 .003

My question is if it would do any harm for me to dust the shims off on my surface grinder to bring the clearances in spec? I'd grind the bottom side of course so as not to alter the surface finish on the top side.

 

Wow! I tell ya what, if you're thinking about doing your shims, stop thinking and just do it! I ground the shims to the midpoint of spec, put everything back together, and took her for a little spin. She sounds way different, a lot less clinking and a lot more base, and has WAY better power and response. Now I just have to break out the Colortune and tweak her in.

 

Hold on. "Ground the shims?" NOT a good idea; they're not hardened all the way through.

One of the forum members is a metallurgist; he sliced a shim and analyzed it with some very sophisticated instruments and posted the results. The bottom line is that grinding shims is not a good idea.

Better to simply replace with a shim that puts you within the specified range.

 

thanks for this bigfitz, It was a huge help!

How did you get the metal lines on the cover so shiny? I tried to polish mine by hand but they still look dull/dirty

 

You're more than welcome; that was the whole idea. The pictures in both books leave a lot to be desired.

The polished aluminum on these bikes was lacquer-coated originally. Quite often the gray stains are UNDER the old clearcoat; it needs to come off first.

I did a complete "how-to" when I did that valve cover; it's in "FAQ Suggestions" as well: http://xjbikes.com/Forums/viewtopic/t=22125.html

The techniques applied here can be used effectively all over the bike.

 

Possible correction:

You say to point the lobes "skyward at a 90 degree angle" Do you mean 180 degree angle? Should the "point" of the lobe be pointing directly away from the shim, like this?

| O>

because the backs of the lobes are not always round, and I've found that it often gives a larger gap reading at 90 degrees, then tightens back up near 180 degrees.

 

Gotta love trig! This is what bigFitz meant by 90 degrees I think. If you think of the flat surface of the shim on the lifter as being the x-axis, then the lobe would be pointing 90 degrees away from the x-axis/shim surface and be the y-axis. If you think of the stem of the lifter then you are 180 degrees away from the direction the stem goes when the valve is opened.

This picture is from an Alfa Romeo but I think it conveys the idea

 

I SAID "at a 90-degree angle to the SURFACE OF THE SHIM"; which is 180 degrees from the direction of the valve stem, true.

The above diagram is a perfect representation of what I meant to indicate.

 

Finally sat down and opened the valve cover to check the valve clearances.

After 47,000 Miles & never ever been done before I had the following:

Exhaust: .007" .004" .006" .003"

Intake: .005" .004" .004" .005"

I am ordering new shims today to bring them back into spec.

Question: The manual says to check every 5K, Could changing the oil every 2500 miles and running 91 octane have allowed me to run so long (47K) without the clearances being any worse?

 

Amazing, Bud, at your worst case the shim is wearing at just 0.012 / 5000 miles. May I ask how you ride this machine? Wiz.

 

Shims don't wear appreciably; the valves burrow into the head. He must 'baby' it. PGDBUD, please start a new thread; you've posted this here and in somebody's Max-X adjustment thread, and it's worth discussing on its own merit.

 

Thanks, Fitz, of course it's not the shim wearing.

 

Excellent job Fitz, my wife and I just returned from Florida after 2 1/2 weeks there missing checking into XJ Bikes. Seemed like I was Disconnected being there with out my computer. I can see though that while I was gone you guys did nothing but get better here in the web site. It sure is a shame I didn't have all those nice pics years ago when I was much deeper into the motorcycles. Seems like just about everyone rides a motorcycle down in Florida. Doesn't seem to matter if there 20 or 80 years old either. One thing I found out when I was there is that last year as I am told the State of Florida increased their State Homestead exemption on property taxes to 50%. Boy with the prices of houses there a guy could sure buy a nice home for cheap and still have cheap property taxes. Something to think on for me. Once again Fitz--->GREAT JOB WELL DONE! grunt007, 81'XJ 750 Seca, Mi.

 

Excellent write-up, Fitz. I dont think i would have even attempted this without your guide. This is exactly what a service manual / technical write-up should look like. I just wanted to sincerely thank you for all your contributions to this site, including of course the rear brake delamination warning. You are both a saint and a scholar good sir.

 

Excellent write up here. I'm a newbie and this write up really helped to muster up the courage and do this. I do have one issue I would like cleared up. I have an 1982 XJ650J Maxim and according to the Haynes book it called out that spec is .16-20 for both the in and exh. But reading through this thread it appeared pretty unanimous that spec is .11-.15 for in and .16-.20 for exh. For my XJ650J is the Haynes manual correct or is this post correct? Because that would change alot of what I need to do.
Cyl 1 2 3 4
Ex .178 .127 .178 .127
In .102 .127 .152 .127
As you can see depending on who's advise I take I could either be at replacing 6 or 4. And for me it's not the work I'm concerned about...it's the operating that concerns me most.

 

The Haynes manual is INCORRECT on that particular detail.

The correct intake spec is indeed .11mm~.15mm.

I only see 3 that need attention, if those are metric numbers (from an American gauge) exhausts 2 and 4 are too tight, as is intake 1. Intake 3 is fine, drop that .002mm and call it .15.

Get yourself a metric feeler gauge; it makes this a lot easier. K-D Tools' #2274 is widely available.

 

Thank you for the confirmation regarding the Haynes manual. I ordered my shim tool and will swap those three out. I do have a metric feeler gauge but thanks for the reiteration on that. Thanks again and I always appreciate your technical knowledge.

February 18, 2012
-I Just replaced Exhaust 2 & 4 and Intake 2 today...finally found the time...Fitz thank you! Your write up made swapping these out NO PROBLEM! And now they are in spec and ready to move onto carb work.

 

Thanks for the nice right up and pictures Fitz! I hope somebody will post pictures and how to for Maxim X too.
Where in Michigan are you from? I am from Macomb County.. Maybe I can come to your place (with beers and chips of course) for a carb tutorial, or mechanical tutorial....

 

http://xjbikes.com/Forums/viewtopic/t=16298.html

Maxim X adjustment.

 

Thanks for the great info Fitz! Going to give it a go this weekend.

Where can I get my hands on some replacement 'donuts'? What are they officially called so I can search for them?

 

Ok so I guess they're "Valve Cover Bolt Seals" ...

This is the cheapest I could find them at $20 for 10.
http://www.jpcycles.com/product/ZZ26668
Everywhere else wanted $6 for 1. Am I doing something wrong? What's with the insane markup? I mean, the expensive ones are OEM, but still.

I'm just not sure these will work though as the K&L catalog lists them for XJ550/XJ750. It's not a different part for the 650, is it?

 

The "donuts" for the 550, YICS 650 and 750 are the same; HOWEVER:

Not all 12 of them are alike. The ones on the eight outer bolts are different than the ones on the four inner bolts.

Did you price them with XJ4Ever?

 

When reinstalling the ignition cover, should loc tite or a thread locker be used on the screws

 

NO. Use anti-sieze compound though.

 

Yo! Dude.
I hope its not too late ...
HCP1622SET8 reproduction valve cover hold-down bolt rubber PRESSURE WASHERS, set of 8:
$ 13.95

 

Those are the outer (8) you also need the inner (4) there are 12 bolts.

 

Don't know if this video ever showed up, but is this guy doing a decent job? I can't tell if he's using a magnetic tool to remove the shims, but that might be a serious mistake he's making...

Other than that?

http://www.youtube.com/watch?feature=en ... 58WrCV-k6Q

 

Question: Will the head ruin a rubber valve cover gasket if I forgot to grease/silicon it? Its glued with that high-tack red sticky stuff to the cover, but during install I forgot to lube the bottom.

Note: this is for the newly acquired 550 of mine. 7 outta the 8 were tight go figure

 

anyone?

 

I would say it would be okay, just might make it a bit harder to pop off next time. Rubber gaskets don't tend to come apart as much like a paper gasket would tear if parts of it got stuck.

But next time you pull it, wipe some on there.

That's my .02

 

It will be fine. Yamaha didn't use any sealer on either side.

 

That bike is not clean......it is sterile!