Valve clearance and shims

Thanks to Bigfitz52 and his awesome valve clearance right up, i checked the clearances and HOLY MOLY. some of my exhaust clearances line up with my intake ones lol.

INTAKE:
1) .004" (.102mm)
2) .003" (.076mm)
3) .003" (.076mm)
4) .004" (.102mm)

EXHAUST:
1) .004" (.102mm)
2) .008" (.203mm)
3) .010" (.254mm)
4) .004" (.102mm)


now i have to wait till tomorrow for my tool to get here so i can see what size shim is in there now. I can't believe theyre this bad

 

You're welcome. HTH.

That is generally what you find when you check a motor that's never had them attended to.

I would roll the motor over and re-check the #3 exhaust valve; it's highly unlikely it's loosened, more likely it's not closing all the way. Check it a few times in case it's sticking.

 

That write-up was part one of my quest to the holy grail that is bike maintenance. You and Rick should put an XJ Bible together. (No pun intended)

 

Turned the motor over a few times checked and checked the numbers. when i corrected the numbers, i did the process one last time and here is the final measurements.


INTAKE:
1) .0045" (.114mm)
2) .0035" (.189mm)
3) .0035" (.189mm)
4) .005" (.127mm)

EXHAUST:
1) .004" (.102mm)
2) .009" (.223mm)
3) .0105" (.267mm)
4) .004" (.102mm)

 

URK. Exhaust #3 may be damaged (stretched) already. It shouldn't be that too loose.

Get them all in spec; and BE SURE you check them again after 5K more miles. You're going to need to watch #3.

Get 'em shimmed up, and run a compression test. Cross your fingers in regard to #3.

 

Yeah that write-up is awesome, and as far is I am concerned, if you can't do it with this write-up sell the bike now, because while I haven't done a whole lot on the bike, I am sure it get far more complicated... I know it does I've read the millions (ok not millions) of threads on carbs and carb syncing.

 

Thank you again. I'm glad you used it to your advantage.

You guys just let me know if you need a how-to on a particular maintenance procedure. If I haven't already done it, I will (or Schmuckaholic will do a "PDF" on it.)

Coming soon: XJ550 rear wheel bearings; headlight and stoplight modulators; re-using YICS valve cover gaskets multiple times and a couple more surprises beyond those.

 

Man... your finger would bleed with just the picture taking alone if I could get any more info and how-to's out of you. Honestly though I think maybe a how-to on 750 specific stuff would be greatly appreciated. I plan on doing one soon once I actually get useful information to divulge. I have a few things I need to tie up so who knows.

 

update:

Got my shim tool today so checked out size of shims installed as of now:

INTAKE:
1) .0045" (.114mm) has 270
2) .0035" (.189mm) has 270
3) .0035" (.189mm) has 270
4) .005" (.127mm) has 260

EXHAUST:
1) .004" (.102mm) has either 275 or 280 (cant read numbers and dont have calipers to check)
2) .009" (.223mm) has 265
3) .0105" (.267mm) has 265
4) .004" (.102mm) has 275

*when checking exhaust 3 the boot was stuck and i couldn't rotate it to the 12 o' clock position. I had to pry it loose with a little force.

So, i was thinking this what i need to get

intake:
1) 260
2) 260
3) 260
4) 250

exhaust:
1) Figured id get a 260 & 265 just in case
2) 255
3) 255 or 260?
4) 260

 

Dude; Your math is all screwey (which is why I recommend a metric feeler gauge.) Since you obviously don't have one, use a metric converter: http://www.worldwidemetric.com/measurements.html

Let's take intake #2: If it's at .0035" then its at .08mm. Installed shim is a 270. Drop it to a 265 and it will be at .13mm, in spec. Put a 260 in there and you've got .18mm, too loose for an intake.

Shims are .05mm apart size wise.

One size and one size alone will put any particular valve in spec; but you've got to get your process cleaned up, METRIC-wise. Bad math is gonna screw you up here, and the chart is so you don't have to do quite as much math.

Let's do exhaust 3: Your metric math is better there, that valve is too loose. If it's truly at .266mm with a 265 in it, a 260 would take it to .316mm,way too loose. A 270 will take it to .216, still a tad loose but I'd stop there.

Exhaust #2 is likewise too loose, it would need to go UP one size to be in spec, going from a 265 to a 270 would take you to .173, in spec (.16mm~.20mm for exhaust valves.)

THINK METRIC. One "size" shim down increases your clearance by .05mm; once size up decreases it a like amount. For those couple that are too loose, you would not fit thinner shims.

Why would you mess with intakes #1 or #4? Spec is .11mm~.15mm. Those two appear to be in spec to me.

You need to go one size smaller on intakes 2 and 3, not two sizes.

All of the exhausts need attention. I'm very concerned about #2 and #3 being that loose. TRIPLE-check those, valve should get tighter not loosen unless something is wrong. I guess it's possible somebody wrongly shimmed them in the past; but those two need THICKER, not thinner shims.

If you can't read Exhaust #1, buy a digital caliper (all of like $12 on Amazon) or pop it out and take it to the auto parts.

Go back, re-do your math, and re-post your choices. I've already done a few of them for you.

 

Do you mean you couldn't rotate the bucket so you could pry out the shim?

If that's the case, then there's definitely something wrong with #3 exhaust, binding. Your take fitz?

 

Good point. Alysiak, if by "boot" you mean "bucket" as in the bucket the shim sits on top of wasn't free to rotate in the pocket in the head and is binding, then DO NOT just shim that valve tighter. The problem needs to be investigated. The buckets must move smoothly and freely in the head.

If the bucket isn't moving freely in the head it could explain the "loose" clearance reading because of binding/not returning properly. Shimming won't correct that. It indicates some sort of other problem, Please clarify.

 

yes, when i went to rotate the bucket for ease of popping out the shim it wouldn't turn. I had to "pull" on it slightly with a hook to slide it into place. It rotates decent now but still not 100%.

And as a side note, thank you very much for the metric conversion stuff. That cleared it up a lot

 

Now you got me stuck into checking my valves. Was going to do today, BUT! The bike runs OK, but could be better. Fires right up with minimal choke (drop off choke in bout 1/4 mile). Gets around 40 MPG @ 70 mph. Hoping to get better. Motor has 35K on it. Runs like scared rabbit. If I get more power out of this adjustment ... OOOOOOOO!! am I in trouble. Great site.

 

Don't discount the possibility of a bit of carbon stuck under number 3 exhaust making the clearance appear wider than usual.

These valves wear progressively tighter not looser and that one is measuring way loose, if it's stuck try tapping it a few times with a bit of wood and a mallet to get it reseated.

I'd shim up all of them except number 3 then crank the engine as fast as you can with the plugs out (but shorted to earth to protect the coils and TCI) then test it again.

It's a long shot but if it is carbon stuck under the seat and you shim to correct, then it dislodges later, you'll then have a tight valve which will burn out in no time, so whatever you do, check them again after running at high rpm for just a few minutes.

 

some of my old math even boggles my own mind. lets try this again lol.

Spec:
550:
Intake: 0.11 - 0.15mm ( = 0.004 - 0.006")
Exhaust: 0.16 - 0.20mm (= 0.006 - 0.008")

INTAKE:
1) .0045" = .11mm (in spec....barely)
2) .0035" =.08mm (out of spec. go from 270 to 265)
3) .0035" =.08mm (out of spec. go from 270 to 265)
4) .005" = .12mm (in spec....leave it)

EXHAUST:
1) .004" = .10mm (out of spec. go from 275 to 265)
2) .009" = .22mm (out of spec. go from 265 to 270)
3) .0105" = .26mm (out of spec. go from 265 to 275)
4) .004" =.10mm (out of spec. go from 275 to 265)

 

Good going. Except I would leave #3 alone right now, until you've had a chance to spin the motor a few times, as iandmac suggested.

Something's not right for it to be THAT loose; valves generally tighten as they wear. You said the bucket was binding; I don't think the valve is closing fully for some reason that MAY not be permanent. If you shim it too tight and then whatever it is "clears out" you'll burn the valve before you know what happened.

Get everyting else shimmed up, go ahead and get your shim for #3 but hold off until you've run the motor after shimming the others. Then re-check. Something's not quite kosher, and you don't want to make a minor problem into a major one.

 

a bit bummed. my local yamaha dealer does even trades (shim for shim) so i got new shims today and they dont fit....arg. They seem to be a bit bigger in size (29.5mm) instead of 29. o well, i guess i'll take em back tomorrow

 

XJ4Ever has shims for half of what the dealer will charge you for new ones.