Hitchcocks Forum

I have re-built my Crusader 250 Sports. Having ridden 85 miles on short settling in tests, the engine is still overheating. I have been careful re-setting ignition timing and adjusting the carb ( new Concentric). This has a 130 jet to suit no air filter, fairly clear exhaust. Not running too weak now, but could be richer maybe. New spark plug and changed condensor to make sure. Any ideas why it seems too hot. or is it normal for this fairly high revving lively engine? Piston has stated 5 thou clearance. Cheers.

Is it possibly pinking? I'd try super unleaded fuel and/or retarding the timing a few degrees.

How do you know for sure that it is overheating? maybe you are concentrating on looking at it too much now. Engines continue to get hotter when stopped after a run as there is no air flowing around the fins. I would advise fitting an air filter for longer life of the engine, if there was no dirt in the air, nobody would have to clean the windscreen on their car or wash it.