I just installed my Yoshimura Duals and noticed that the rear head pipe is turning blue. Does this mean that I need to jet the carbs or whats the deal? I have a K&N filter and the dual yoshis with stock jets. (live at 5200 ft) Is this something to worry about or is this normal. By the way the pipes are stainless not titanium or anything.

 

a blue pipe is not to much to worry about. heck mine even turned a permanent shade of gold. what yeah gotta worry about is if the pipe glows red. check it in the dark after 5 minutes of good riding. i live at 3000 feet above sea level and i went up 15 from the recommended jetting. i am at 165 main with my 400. its running a bit rich but im planning on putting a cdi on so its ok lol. hope this helps

p.s. if you still feel uncomfortable go ahead and get it jetted again. remember running rich is ok but running lean will kill yeah.

 

Thanks for the reply, makes me more comfortable now. Is there a symptom for running lean or not? It runs perfect, so I dont know if I could tell if it was running leanor not.

 

you could do a spark plug check. Plugs change colors and the different colors can explain such things as if the engine is running too hot or if the engine is worn. The color should be read by looking at the porcelin insulator...
--A tan colored plug means that the engine is running normal and the air/fuel mixture is correct.
--A black dry fluffy colored plug is caused by deposits from a carburetor that is running too rich (too much gas).
--A black wet glazed colored plug is caused by the burned oil that is leaking past the piston rings or valve guides and burning in the cylinder.
-- A white colored plug is caused by engine overheating. Common causes for this are:

* Incorrect spark plug (too hot heat range).
* Low octane fuel.
* Timing is not set properly.
* Cooling problems, (dirty cylinder fins, no or low water if water cooled, low or no engine oil).
* Carburetor air/fuel mixture is too lean (too much air).

So if its white its lean.