No real problems with those saito induction tubes when running, especially on methanol... the increase in engine temperature running on gasoline can change the thermal behaviour... unless there's poor airlow around the engine, or the cylinder is running very hot from too lean mixture... I didn't expect any issues with that F50R, but there was... it has a threaded 16mm induction tube with a aluminum mounting flange for the carb... the induction tube and carb are curves around the backside of the cylinder... I believe its more of a radiant heat issue, as I also have a .010" thick aluminum firewall plate, at the time I thought it was a good idea, but maybe it aggravates the radiant heat absorbed into the carb, as the carb body is just a few mm's off the firewall, fortunately the inlet is not facing the firewall.
Last edited by John_M_; 10-01-2022 at 11:42 AM.