Valves clearances

[Shane4371]

The lobe is actually very smooth .the side I showed was up.catching my feeler gauge.the cam lobes are all very smooth.im gonna have to remove all these shims and check.

[CutterBill]

...should I remove this head and start over?

No. Unless the valves are burned (you can determine this with a leak-down tester) pulling the head won't fix anything.  

Replace that mangled shim with a good one.  Remove the rest of the shims, one at a time, and see if they look like that.  Replace any that don't look smooth and shiny.  Take your time and get the valve clearance right. Install shims with the numbers down; that way they don't get wiped off by the cam.  Buy some metric feeler gauges; they're cheap and I suspect you are getting confused with the converting back and forth. You might want to invest in a 0-25mm metric micrometer; this will make determining the thickness of the shims much easier.

It's a metric bike.  Use metric tools.

Check very carefully for intake leaks around the rubber connector between the carbs and the head.  Yamaha calls them "Carburetor Joints."  You might want to remove them and replace the O-rings that live in there.  The tiniest vacuum leak will cause giant headaches.  If they are hard and/or cracked, replace them all.  Randy (RPM) has them for a most reasonable price.

And as for the "running the engine up to operating temp and then letting it cool overnight" between valve clearance checks... in all the years I have worked on shim-over-bucket engines, I have never heard of this one.  Nor can I think of any sound engineering reason why you should do so.  I doubt Yamaha (and Audi and VW and Volvo) does this on all of the thousands of engines that they make. Now, you might want to turn the engine over by hand one revolution to ensure that the cam lobe has pushed the shim firmly into place.  Yeah, I do that.  But run the engine and check it again the next day?  Nah...

Bill

[Firehawk068]

Hooligan may be right?
It certainly does look like it used to be a quarter..........

[FJmonkey]

Or maybe used an angle grinder to make a thinner shim.

[Pat Conlon]

....Now, you might want to turn the engine over by hand one revolution to ensure that the cam lobe has pushed the shim firmly into place.  

That's just it Bill, ^^^ Turning the cam lobe will not fully seat the new shim. If you take a follow up measurement you will find it to be tighter than it really is..

As it was explained to me: The FJ head pools oil around the buckets. When you pull a shim out, the buckets fill with oil...
Remember the squirt of oil we get (in the face) when we roll the cams with new shims installed? Fun huh? It's a rite of passage with our FJ's.
That's the accumulated oil in the bucket that's squirting you in the face.
This accumulated oil will mess up your follow up measurements....you will drive yourself crazy.

I think we all agree to check your valves on a cold engine.

You are correct, it's a hassle to "have to" go back the next day and remeasure...However, I don't think anyone is saying that you "have to"...there is no need to remeasure. I don't.

However if you do, 1) get all the excess oil out of the buckets first  2) do the recheck on a cold engine.

Cheers.

[CutterBill]

If you're really worried about trapped oil, then just crank the engine over a few times with the starter.  The spark plugs are out, anyway.  Easy, peasy...

[racerrad8]

How does the cam lobe look?

I swear that looks like it used to be a quarter.  When swapping shims around, a quarter can be used as a temporary place holder.

Looking at the side, does it look like it's a metal sandwich?

All we need is a photo of the other side.

Randy - RPM

[racerrad8]

If you're really worried about trapped oil, then just crank the engine over a few times with the starter.  The spark plugs are out, anyway.  Easy, peasy...

Bill,

After building hundreds of these engines and probably adjusting a million valves in my twenty plus years of working this engine, cranking the engine over will not allow the oil to be fully extruded out. There are a few reason why this is.

1) The valve shim & bucket are held in a pool of oil at with at least 25% of the shim & bucket covered with oil when the engine is shut down.
2) As a machinist, you know about the centering/reference hole for machine purposes. Well, the surface under the shim has a centering hole that allows the oil to pool.
3) Oil viscosity and ambient temperature is going to be dependent on how easily the oil is extruded.
5) The seat pressure of stock valve springs is only approximately 42-50 PSI on a new Yamaha spring, you can only imaging a 30 year old motorcycle having seat pressure much lower than that. That also reduces the ability to extrude the residual oil.

I wear out a valve shim tool every year adjust valves. Depending in all of the variables above, I have noted as much as a .002" difference. I have attempted to "spin the engine" to try and eliminate an variable due to trapped oil. That measurement is always tighter/smaller than is it after the engine has been brought up to temp.

I rely 100% percent on the chart Yamaha provides, based on the correlation of the shim thickness that has been removed. I never measure them again until after the engine has been brought up to operating temp to ensure the oil has been completely removed from the underside of the shim.

Randy - RPM

[fj1289]

Or maybe used an angle grinder to make a thinner shim.

I'll bet this - but the grinding probably went through the hardening and the softer metal got chewed up by the cam.  IF you were going to do this - you'd have to install the shim ground side down so the cam worked on the side that is still hardened.

[CutterBill]

After building hundreds of these engines and probably adjusting a million valves in my twenty plus years of working this engine, cranking the engine over will not allow the oil to be fully extruded out. There are a few reason why this is....

Strangest thing I ever heard...   

[Shane4371]

I had the shim measured it turns out the measurement was a 2.60, .009 slid in easy,I purchase a 265 and .008 barely went in,ask power spots didnt have the other 4 shims i needed so RPM has my order coming,I put everything together ran the engine till it reached operating temp.thiers a considerable change i how its running when i get the rest installed ill resynch carbs and test ride,vey excited

[Shane4371]

I'm currently waiting on 4 additional shims to complete my project,the question I got,my worst valve was very loose,by that I mean I could almost go over
009 with my feeler guage .006-.008 is spec for exhaust,a 260 was replaced with a 265 that made.008 perfect is their a better spec I could of got ?

[FJmonkey]

I'm currently waiting on 4 additional shims to complete my project,the question I got,my worst valve was very loose,by that I mean I could almost go over
009 with my feeler guage .006-.008 is spec for exhaust,a 260 was replaced with a 265 that made.008 perfect is their a better spec I could of got ?

I think you picked a good shim, it puts that valve back into the middle of spec. 

.009 inches needs .002 change to get .007 (nominal gap) inches. A .002 inches in change equals .051 MM increase of thickness and you will not find a 2.651 shim without a micrometer and it really is not worth the effort.

[Shane4371]

On my intakes I'm 270 across the entire intake side,I'm at .005 on 2 intakes .004 is the lower end of spec is 265 would be to bigg a drop should I leave it.I'm thinking when she's warmed up that's gonna get tighter

[FJmonkey]

On my intakes I'm 270 across the entire intake side,I'm at .005 on 2 intakes .004 is the lower end of spec is 265 would be to bigg a drop should I leave it.I'm thinking when she's warmed up that's gonna get tighter

The numbers are cold numbers and account for a warm engine, you don't need to over think it. Use the cold numbers....