No Valve Lash

[hudson]

Thanks gspd. I have always done the side that the rods are lose and spin at OT. I also appreciate the input on the adjustments. Yesterday, I did insert and rods and rotated the flywheel and confirm that the valves were opening and closing. As I stated, I couldn't remember if I paid attention to that or not (LOL). I only had a few minutes so I didn't troubleshoot more.

I am convinced I am missing something not so deeply involved in the installation process since I have done this before on airheads and guzzis. The reminders are great though and help me make sure of things. It will be something much smaller in detail either with the followers or the rockers themselves. I will work on this on the weekend and I already have a clearer head to pay attention to detail. Last weekend I was in a hurry up mode which made me impatient and frustrated. Let that serve as a lesson

[Kurt in S.A.]

Just as a side note, and something of a pet peeve of mine. I read where it's suggested to rotate the engine and find out which set of pushrods spin which will indicate that's the side to work on. In a perfect world, I agree. But if for some reason the valve clearance has completely closed up, there will be no spin no matter which side you check at OT. So, I never rely on that.

I always remove the valve covers, put the trans into high gear, and get behind the bike and rotate the rear wheel. I watch for the left intake valve to open and then begin to close. I know then that the left side is approaching TDC on the compression stroke. I reposition myself by the timing hole on the left side and bump the rear wheel with my hand. I watch for the F, S, then finally OT. I can then set the valves regardless of whether they spin or not. To be anal, I'll do the same thing for the right side. Or you can just rotate the flywheel one revolution.

Now back to our regular show!!

Kurt in S.A.

[jagarra]

Have you checked the overall height of the valves, are they too long or are they in specs?? Did they install new valves or did they regrind your old ones?

[gspd]

Kurt said:

I always remove the valve covers, put the trans into high gear, and get behind the bike and rotate the rear wheel. I watch for the left intake valve to open and then begin to close. I know then that the left side is approaching TDC on the compression stroke. I reposition myself by the timing hole on the left side and bump the rear wheel with my hand. I watch for the F, S, then finally OT.

There is no need to watch the for the F, S and then the OT mark. There is no point in even removing the inspection plug except when setting/checking the ignition timing.

There is nothing wrong with the way you are doing it, but If you want a short cut with the same results, simply rotate the engine with both valve covers off and observe when the exhaust valve is closing and the intake valve is opening and find the approximate middle point of their travel in relation to each other by slightly rocking the crank forward and back and then adjust the other side.
You don't have to be 100% precise, you could theoretically be 90 (crankshaft) degrees off in either direction and it would make no difference.
if the exhaust is closing and the intake is opening on one side, the other side is safely well within the 180+ degree flat part of the cam. You can safely be 90 crankshaft degrees away from OT (180 camshaft degrees) and set valve clearances.

To sum it up, it makes no difference if you are on F, S, or OT, or way before or way past, when you adjust the valves, the result will be the same providing the other side is anywhere within the overlap.

If you have a loose cam around, examine it and you'll see what I mean

[Kurt in S.A.]

I get your point, gspd. I know from geometry for something like a sine way, that one could be maybe 5% either side of the actual peak and it wouldn't really make a practical difference. However, in the engineering world I dealt with, it would make a difference. So, I tend to want to be within a tight window. I'm not saying that the cam profiles are not anywhere close to a sine wave shape. Since it's not, the idea that you can be anywhere within shouting distance and it would be fine. I suppose sometime I could find OT and slip in a feeler gage such that it is help firmly and doesn't drop out. Then I could start moving away from OT and keep checking the feel and find that point where it becomes much harder to move the feeler gage. I guess that would give me a better sense of the range you're talking about.

My point was that the idea of looking for the situation where the pushrods spin to identify what side you should be working on is not sufficient in all conditions. I prefer to see the valve action and know precisely where the engine is in the cycle.

Kurt in S.A.

[gspd]

Kurt said :

the idea that you can be anywhere within shouting distance and it would be fine

LOL!

That's exactly it.

By design, the clearance between a cam lobe and a lifter remains constant for a minimum of 180 degrees of the cams' rotation.

And I agree about not considering which pushrods spin freely to determine which side to adjust.
I've seen too many recessed valves and botched assembly/adjustments to use that method.

It's good to know that valves can be precisely adjusted without relying on the flywheel marks; I have adjusted valves on hundreds of engines that have no easily visible/usable timing marks; you simply have to go by the lobe's position. I've even seen airheads that were put together with the flywheel in the wrong position rendering the marks useless.

Just wondering... could I possibly convince you that feeler gauges are more time consuming and less accurate (ie, useless) than a specific (and very easy to figure out) amount of rotation of an adjuster that has an exact 1mm pitch?

Hudson - sorry if I'm hijacking your thread, but it was entitled Valve lash after all.
BTW - Are you sure the 2-3mm gap you get when you loosen everything isn't simply the pushrod seals decompressing?

[jagarra]

Since we have gone how to adjust the valves over and over with no change in the results for Mr Hudson, maybe we should look at the work that was performed. If the components involved in the rebuild are not within specifications he will never be able to adjust the valves correctly. The bottom end wasn't touched, no change in flywheel position or cam timing. He indicated the barrels are seating correctly, if the heads are seating correctly (correct base and head gasket thickness) then the only items that could affect his issues are pushrod length (if original or changed) ) or the over-all length of the valves. My Clymer book indicates that the length should be 98.4-98.8 mm in length for intake and exhaust. Is the seat depth correct, too deep?

[hudson]

I am not sure I am totally being understood. I do know how to do a valve adjustment and a top end removal and install. And I know how to find OT. That is why I am scratching my head and keep thinking what the heck is the deal...

I just wasn't paying attention to the valves opening and closing as Kurt said, which made me doubt if I was on the right revolution. So I purposefully watched and tested it out the other day to make sure valves were opening and closing, the followers/rods moved unhindered, and I made sure I was going the full revolution to the right OT mark. I was too frustrated to remember what I noted to be weeded out of the equation. But that is now confirmed.

The valves are the ones that have already been in the head, working fine, and they and the seats still have life on them. I just cleaned everything up and put new springs on, since they were just out of spec.

I agree jagarra, if all was working prior to the teardown, it is an reinstall error on me, or the new variable introduced - the new parts. I tend to think this is not the case. I am back to foolin with it tomorrow. I am 99% sure that is something stupid that I did. It has to be. A top end install is not rocket science, right?

That said, all of the brainstorming is valued from everyone. I will report back and inform, even though it will probably be something really dumb.

[Roy Gavin]

On page 2.26 of my Haynes manual drawing 33.7 is annotated - Do not forget spacers or o-rings(where fitted)- before installing rocker assemblies -------

[jagarra]

Gee Hudson, now that you have blown the variable of new parts out of specs, we really have a brain teaser. Hope you don't find a missing spacer in your solvent tank. Or maybe I do...

Now that I think about it, did you disassemble the rockers shafts from the towers when you were doing the heads, are the towers the same for the intake or exhaust, could you have mixed them up?