I am a norton owner again! It's been awhile. I am currently sorting out a 71 commando that sat for 13 years. I have sorted out carb,rat chewed wiring,fluids, Clutch (that came out in one solid clump) etc. I't now lights up and sounds good. But i noticed left header is bluing further down than usual and appears to runs hotter than right. Running single mikuni and oil seems to be running thru head evenly.Any ideas? Maybe cheap header on left side?