I attempted to adjust valve clearance on my 99, and upon removing the cover I checked clearance on exhaust side. I noticed that the left valve on each cylinder had smaller clearance than the right one - some were so tight I coud not insert the feeler in there.
I made sure the cam lobe was opposite to rocker when testing.
It looked like both exhaust lobes were in sync, and for cyl 1 and 4 the clearance was large enough to insert the feeler, not so for 2 and 3. Even for 1 and 4 you could tell the drag was more for the left valve.
Did not see any mention in Honda Repair Manual about that. Anyone seen that?
I bought the car used at 27K, no reason to believe someone played with it, but you never know.

 

When's the last time it was adjusted? If it's been all of 140k miles, I'm not surprised some were different.

Cold engine when you're doing this?

 

Hey Jim - my first time to open up. I realize the clearances would be loose, but why are some tight? Engine cold. Car is now at 160k. It's like I was using the wrong feeler.

 

Intake vs. exhaust are different; they're on opposite sides so you probably didn't confuse that way.

I don't know why, other than it's been my experience that they don't ALL go the same way ALWAYS.

 

I had a 90 Accord that I sold w/ 270K miles. I never adjusted valve, although I checked them a few times. They were always near the specs and made only a little noise when cold, so I left them alone.

Make sure the cam lobe is in the fully loose position. The shop manual says to turn the engine to bring each cylinder to TDC before checking the valves on that cylinder. I always thought that was silly as long as the lobe was fully rotated out of the measurement path. You can usually measure about 1/2 the valves in one position, then rotate to bring the others to a loose position.

good luck