Valve clearances...HELP!

[mich1jon]

After researching the whole valve clearance topic until my fingers were callused and numb, I dove in and checked my clearances; armed with all the knowledge I gained here, a VAT which I ordered from Randy, and a new set of feeler gauges that didn't have rust on them.
Here are the measurements I took, which I must say are puzzling (at least to me).

Intake:
1A-.190
1B-.216
2A-.152
2B-.165
3A-.152
3B-.178
4A-.152
4B-.178

Exhaust:
1A-.229
1B-.229
2A-.203
2B-.203
3A-.190
3B-.216
4A-.229
4B-.216

Do these numbers seem a bit on the large side?
I went through the measuring process 3 times, like someone suggested, and then did it a 4th time! (because I was waiting for the VAT to arrive.)
Now that I've  checked the shims and done the math, it appears I need to put in LARGER shims to meet specs!?
I thought the clearance was supposed to decrease with time/ wear.

Any thoughts on what's going on?

[fj11.5]

I could be wrong, but larger shims increase clearance, valves close up / tighten over time, so you lose clearance at the valve seat , not at the shim, so i would say your correct

[zz28zz]

Assuming you checked the clearances with a stone cold eng, they are a little large. As time passes, the valves will sit deeper and deeper into the seats which decreases valve lash (clearance).
Normally you would be expected to install thinner shims as time goes by.
However, if there is abnormal wear on the cam, shims, or valve stem, the clearance can increase. Assuming the eng has always had sufficient quantity and quality of oil, this should not happen.
Most likely, the prev adjustment was not done correctly or your measurements are not accurate.

I would make the necessary adjustments and keep an eye on it. Keep good notes and track clearances for a while.

It's much better to have too much clearance then not enough.

[mich1jon]

Assuming you checked the clearances with a stone cold eng, they are a little large.  

Most likely, the prev adjustment was not done correctly or your measurements are not accurate.

I should mention I'm the original owner and there were no previous valve adjustments made to this bike. The only oil I've ever used was Golden Spectro and levels were kept up.
I followed all the procedures as they are outlined on this website as well as 2 other sites and can't understand how the measurements could be inaccurate. There is the potential to obtain measurements that would be too small, but measurements that are too large?
I'm just afraid someone is going to respond and use words like "bent", "replace" and "valve job".

[FJmonkey]

I should mention I'm the original owner and there were no previous valve adjustments made to this bike. The only oil I've ever used was Golden Spectro and levels were kept up.
I followed all the procedures as they are outlined on this website as well as 2 other sites and can't understand how the measurements could be inaccurate. There is the potential to obtain measurements that would be too small, but measurements that are too large?
I'm just afraid someone is going to respond and use words like "bent", "replace" and "valve job".

You mentioned taking your measurements 3 to 4 times. What if there is an error in the way you are taking the measurements? I am not suggesting that you don't know how, but I have made basic errors on simple projects like this. I do something over and over and kept getting the same results that I knew could not be right. After some thinking it through I found my error and all was right again with my world. Do you have a friend or neighbor that can take measurements double check your results?

Also, if your valves are that lose, some of them should be tapping. My #1 intake valve had a gap of .178 and I hear it tap during idle. I see 4 of your intakes have gaps as big or bigger, they should be pounding out like a drum team.

[zz28zz]

How are you getting such precise measurements?
You either purchased a very large set of very high precision feeler gauges, or you were using multiple feelers stacked on each other and adding them up..
It's almost impossible to get accurate measurements when stacking feelers.

I use a basic set of SAE feelers. If the .004" fits and the .006" doesn't, the intake is good. .006" and .008" for the exh.

If the valves have never been checked, it's possible the factory worker goofed.
I have the up-most respect for Yamaha quality, but I suppose anything is possible..

Next oil change, cut open the filter and inspect it closely. Hope for no shinny chunks..

[racerrad8]

I also only use SAE feeler gauges and adjust to .006" intake and .008" exhaust

Also, make sure the lobe is pointed straight away from the valve when checking clearance.

A thicker shim will decrease the clearance as the cam on bucket clearance is directly relevant to the shim thickness Vs. wear.

Most of the time the shims are always going to decrease in thickness as the valve seats deeper into the head and the lash in decreased.

Randy - RPM

[mich1jon]

Also, make sure the lobe is pointed straight away from the valve when checking clearance.

Randy - RPM

I believe you've solved it, Randy
BUT, here's where I think the problem began. My Clymer manual says to turn the engine to get the timing marks to align with the marks on the timing sensor, indicating top dead center. (I also verified this by using the technique outlined by Marsh, sticking a rod into the spark plug hole and turning until it is at TDC. The marks and the rod method agreed with each other.) This puts the intake lobe for that cylinder pointing backwards while the exhaust points forwards, away from each other by 180% as mentioned in the British XJR forum post which simi ed posted the link for.
BUT- the picture in the manual has the lobe pointing straight up, at a 90% angle from the cylinder head!?
Having the lobe point away from the valve makes the most sense to me, and after remeasuring I obtained measurements which were considerably more reasonable.
Thanks for the tip Randy, and thanks for getting all my parts and tools to me so quickly.

And thank you, everyone, for the input. 24 years ago when I purchased this bike the only support that was available was from the dealer, and it didn't come cheap! I think it's time to write Marsh a check.

Cheers!

[fj11.5]

what page in the clymer is it, ill check it against mine , and compare it with what the Hayes and Yam manuals show, wouldn't be the first time they give the wrong info, , think we should make our own with all the info from here

[Pat Conlon]

I never understood that info...turn the crank so many degrees this way....etc...
Are they trying to make it complicated? On purpose or is there another reason?

How about just saying:
Turn the crank counter clockwise until the cam lobes point 180 degrees away from the valve, and measure.

There...17 words to replace an entire section of gobblygook.

[Super_v500]

Just to be clear, what's the correct way? I'm doing mine tomorrow, after reading the haynes manual, it's the clearances when the cams are facing away from each other not when they are pointing up and away 180 degree from the valve.

[mich1jon]

Well, the general consensus seems to be to measure when the lobe is pointing 180 degrees (away) from the valve. That's what I finally settled on, and the measurements I obtained are within the acceptable range.
When I measured it the way Haynes suggests, the results dictated my putting in a shim that is so thick, it doesn't even exist!

[andyb]

If the lobe is facing 180 away from the valve, the lash measurement should be at the largest possible distance.  With the lobes pointed to each other, the clearance should be smaller if anything, requiring a thinner shim.

You may want to measure perhaps more carefully, something ain't right.  The only way the distance would become greater with the lobes twoards the bucket is if the cam itself somehow became bent.

-----------


To clarify, if things are in spec with the lobes pointed dead away, you're likely just fine, but I expect that the measurements weren't accurate the other way.

[WestOzXJR]

Here are the measurements I took, which I must say are puzzling (at least to me).

Intake:
1A-.190
1B-.216
2A-.152
2B-.165
3A-.152
3B-.178
4A-.152
4B-.178

Exhaust:
1A-.229
1B-.229
2A-.203
2B-.203
3A-.190
3B-.216
4A-.229
4B-.216

Do these numbers seem a bit on the large side? ......

......Any thoughts on what's going on?

Looks like your feeler gauge(s) are metric. 1mm = .03937" (inches)...

So as an example, from you above actuals, Exhaust 4B >>> you measured @ .216 (mm) x  0.0397 (conversion factor) = .00858" OR 8.58 thousandths of an inch.

So to set from your feeler gauges to specification/advice of others >>> set (intakes@.006") .006/.0397 = 0.15mm, (exhausts@.008) .008/.0397 = 0.20mm

[RichBaker]

 1st time I checked the valves in my '90, I did it the book way, and came up with some weird #s, don't recall what they were. But, as I had a few years experience as a car mech, I went to the "point the lobes 180 away" method and got more believable and consistent #s.
Seems like every time I turned the crank and rechecked using the book method, the #s were different for the same valve. It shouldn't vary, as long as you are on the "base circle" of the lobe, but it did...   
So, I always use the "pointing away" method.