tappet bore wear

[108]

Does anybody here have an opinion on which tappet bore (if any)would be most likely to be worn the most on a Panhead. I have a '48 with replacement alluminum tappet blocks' Dont know that I have a problem , but I'm going to be checking the valve adjustment soon(solids)for next summer and just wondered.

[Cotten]

108!

The front exhaust, of course.

....Cotten

[108]

Thanks Cotton, I can see how the front exhaust would wear the most with the push rod at the greatest angle. Last night I set up a dial indicator on the adjuster lock nut, which I realize is a little above the bore but with for and aft pressure I can get .005 movement . This fall the front exhaust had been a little louder than the others when is was really hot but last night I found the the cold adjustment was about .002 more than zero lash, so that may be why. Now I'm trying to decide if the '.005 clearance is worth correcting or should I just run it a couple more years and recheck. Have you ever fitted the oversize tappets that are available? Thanks for any advise.

[Cotten]

108!

The front exhaust is also the last in line to get oil.

Aluminum blocks have the fatal flaw of embedding particulates. Once the clearance has reached the point where a micro piece of carbon or steel can enter, the aluminum will hold it like a toolholder to cut and cut and cut.

Sportster people (the ones who pay attention) often note greater wear upon the tappet than the bore. Early Pans are not immune.
You may be able to take up clearance with just a fresh tappet, but be certain the bore shows zero trace of anything stuck in it.
(Everyone should beware that glass bead residuals will be invisible!)

Fitting an oversized tappet only requires a Sunnen "keyway" honing mandrel.

...Cotten