I was out riding in the snow the other night and it was about 20* out. I pulled up to my brother and he said my header pipe was orange. Sure enough, the first 3-6 inches of my header pipe (depending on how much the engine was revving) was a faint orange. Is this ok or is this a sign of a problem like running rich/lean or clogged exhaust?

Its a stock 2002 Warrior.

One other thing... it was only after doing a minute or 2 of donuts and not really moving forward so air-flow wasn't great. Because it's air cooled, I assume this is ok since I was revving high and not creating much airflow during the donuts?

 

usually when a bike is running lean it will do that, being as cold as it was that night makes it run leaner then usual i believe its called a lean burn or something, most likely its fine its normal on some stocks atvs actually.

 

Yea I've run bikes on the dyno where the whole exhaust back to the muffler was orange and the first few inches was almost white. It might be a little harder on it considering how cold it was and the tires might throw snow on it but it should be fine. It probably happens more than you realize. I wouldn't think there was a problem unless you have noticed it loosing a lot of power lately.

 

Yea its running lean.

 

It is does happen a lot, but is more visible on overcast days or at night...your valves could be tightened/adjusted some....but if it runs good why muck with it....what octane fuel do you use? Anyways....happy trails to all Maine

 

Running lean is bad, very bad. Running lean may slightly enhance power, but it makes the engine run much, much hotter and substantially increases the possibility of heat related issues in the head and piston, such as seizing etc. What elevation do you live at, because an all stock bike shouldn't be lean unless its been changed before or if there is something aftermarket on it.

 

How can you tell if it is running a little rich/lean?

 

most definantly running lean! it'll probably be ok but too lean can be destructive like seizing piston!
if anything it would be good to run a little rich to make sure its doesn't run lean in the cold[img]i/expressions/face-icon-small-smile.gif[/img]

 

<div class="FTQUOTE"><begin quote>Originally posted by: Swerve

How can you tell if it is running a little rich/lean?</end quote></div>

Look at the spark plugs. If they are white its lean. Golden prown is just right. Black or dark brown is rich.

 

so far everything everyone else has said...ditto. But to go off of what beefy said, one of my mechanics I used to go to always gave my quad back to me lean when he was done with it. So even if it is stock, if you have had anyone work on it I'd play with the carb first to solve the problem (but like sparky said...check your plugs and that'll tell you right away.