AJS & Matchless Owners Club

Hi, many years ago a mate of mine had a Matchless G2 with a chrome exhaust pipe and Matchy megga, i remember that he replaced the head gasket, put everything back and started the bike, the exhaust pipe from the head started to glow a dull red, i know he sold the bike in the end because he couldn`t stop the pipe glowing, just for info what could have been the possible cause.

Timing & fuel/air mix springs to mind
shifter

Yes, retarded timing (and possibly a weak mixture) would raise the exhaust temperature considerably.