Topic: Blue colored exhaust - 3 of 4

[ljanders]

Hello,

I'm having an Yamaha 600 Seca II. (Yeah, but I'm having an CB400/4 also...). Now I have polished the exhaust pipes (stainless) and then I tried to syncronise the carbs. After this process (10 minutes reving, somethimes up to 5000 rpm), I took a look at the exhaust pipes. 3 of four pipes has turned into a blue colour!

The bike is equipped with 2 ignition coils, and the ignition system is electronic. What kind of fault is this indicating? I suppose all should have the same colour?

[SteveD CB500F]

Blueing of the chrome is caused by overheating.  Most Hondas of our era had dual skinned pipes so that this didn't happen.

Unfortunately, most aftermarket exhausts didn't...

[cben750f0]

may just meen that you havent got the set up quit right yet, and that the other three cylinders are doing the work...start one morning, and dont rev it, as it tries to idle .. check the temp of the pipes... you might find that the one that isnt blue will be cold, while the other three start to warm up... check for carb gallery blackages... could be a prob... peace

[phylo101]

Yep, its heat does that.... BUT what did you use to polish them??? If there was some polish or whatever still on the pipes this sometimes affects the cooling properties JUST long enough for the blueing to occur at a different temperature than it should do.

phylo