No flak from me Scottie and I'm not going to say 'I told you so' about the flip front. Damn, I just did.
Thinking about your overheating issue, these old Triumph engines tend to get airlocks in the block which leads to overheating despite the radiator remaining full of coolant and the system being otherwise capable of keeping the engine temperature within normal operating parameters.
The trick is to remove the top hose from the 'stat housing and back-fill the block through the housing rather than expecting any trapped air to make its way out to your header tank, which from experience it just won't.
I also put a bleed point with quite a large removable cap on my heater outlet hose and I also back-fill the heater circuit and block from that to ensure that there's no trapped air in the system.
Thinking back to the days of driving around in the 70's and 80's in old clunkers that kept boiling over, I reckon most of those cooling problems were just caused by airlocks in the block.
Anyway, Spring is on its way so get out there and fix your ride.
