Am I right in thinking that a) discolouration is exacerbated by incorrect fuel/air mixture and that b) some bikes have double skinned pipes that don't discolour?
Certainly the early M3W front pipes were single skinned ferritic stainless steel, so they will go a golden brown colour after a while of use. This will polish out to then repeat in time. Q? Are they now chrome plated? Cheers PJB.
Am I right in thinking that a) discolouration is exacerbated by incorrect fuel/air mixture and that b) some bikes have double skinned pipes that don't discolour?
Yes. An over lean mixture can cause overheating with high exhaust temps which in turn are likely to turn exhausts blue. An over retarded ignition timing can do similar things. In reality all pipes go blueish with normal operating temperatures especially close to the head where they are highest. Some bikes have double skinned so the inner skin discolours but the outer stays ok, Harley has covers that do the same.
Every thousand miles or so I take my Mothers Mini-Power Ball to the headers using Blue Magic metal polish and they stay rather presentable. The Blue Magic has a compound that stops the pipes from browning and whenever they are due for another polish they have a black sheen to them where they heat up the most, that easily polishes off.
OK, so are the later exhausts mild steel with chrome plate? In which case the will go blueish if overheated? The first pipes were ferritic stainless steel and will never go blue, these will go golden brown. The corrosion on ferritic stainless will polish off back to the alloy. Just interested. PJB
Am I right in thinking that a) discolouration is exacerbated by incorrect fuel/air mixture and that b) some bikes have double skinned pipes that don't discolour?
Yes. An over lean mixture can cause overheating with high exhaust temps which in turn are likely to turn exhausts blue. An over retarded ignition timing can do similar things. In reality all pipes go blueish with normal operating temperatures especially close to the head where they are highest. Some bikes have double skinned so the inner skin discolours but the outer stays ok, Harley has covers that do the same.
