I had an 848 head rebuilt with bronze guides and lip-type seals. They were set up with about 0.0015 clearance. I had one exh valve hang up and the engine started missing. I shut it down and let it cool then gave the adjustable main jet an additional 1/4 turn out. Problem solved. This was a cool, dry morning below sea level in AZ. They seem just fine 30,000 miles later.

Last edited by Phak1; 11/26/2025 1:00 PM. Reason: Typo
1951 3800 1-ton
"Earning its keep from the get-go"
In the DITY Gallery
1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.