alancoles
Dress for fall & avoid it
John, like you, no wish to highjack thread, perhaps the moderator could copy post #14, and move posts #18, 20 and this one #21 to a new thread "Exhaust Bluing" under "Wetheads".
Bluing is normal and I'm definitely no expert on this but it is my understanding that extreme exhaust bluing (as may be shown in your post #14) is most often the cause of a lean burn situation. Wondering if there is someone who has some real-world expert knowledge on the matter could chime in. Pictures can often be deceiving so it may not be as strong and heavy a bluing as it looks to me, and that may well be the case, because the pictures in post # 20 all look fine and normal.
My 1970 Norton 750 had a carb problem when it was rebuilt last year and really blued the header pipes quite a bit.
To me, slight-medium bluing and the goldish colouring is normal, medium-strong bluing is typical of a bike that's been ridden in a spirited manner for extended periods of time (not bad unless it has been ridden too hard and put away wet, so to speak), but really strong blueing always makes me think high exhaust temperature (EGT) conditions, which is most often caused by an overly lean mixture. Checking your spark plugs is a very quick and easy way to identify an overly lean mixture (white vs normal charcoal to light brown) . If you had access to it, hooking up a pair of wide-band O2-Sensors and a Data-Logger would tell you everything right away, but a quick plug read is all that is usually needed. Like I say, I'm a novice in this area.
Bluing is normal and I'm definitely no expert on this but it is my understanding that extreme exhaust bluing (as may be shown in your post #14) is most often the cause of a lean burn situation. Wondering if there is someone who has some real-world expert knowledge on the matter could chime in. Pictures can often be deceiving so it may not be as strong and heavy a bluing as it looks to me, and that may well be the case, because the pictures in post # 20 all look fine and normal.
My 1970 Norton 750 had a carb problem when it was rebuilt last year and really blued the header pipes quite a bit.
To me, slight-medium bluing and the goldish colouring is normal, medium-strong bluing is typical of a bike that's been ridden in a spirited manner for extended periods of time (not bad unless it has been ridden too hard and put away wet, so to speak), but really strong blueing always makes me think high exhaust temperature (EGT) conditions, which is most often caused by an overly lean mixture. Checking your spark plugs is a very quick and easy way to identify an overly lean mixture (white vs normal charcoal to light brown) . If you had access to it, hooking up a pair of wide-band O2-Sensors and a Data-Logger would tell you everything right away, but a quick plug read is all that is usually needed. Like I say, I'm a novice in this area.
