Red hot exhaust manifold

[docjones]

Saturday I purchased a 06 GV with 136 miles on it. (a barn yard find) Needless to say it sat a lot. After spending about 7 hours cleaning the scoot and the carb (carb was really bad) changing the oil, I got it started. After it was good and warmed up it idled just fine. I haven't had a chance to clean the gas tank out yet so I'm using the tank from my outboard motor. (not a 2 stroke) After that first run in the garage for about 30 minutes I change the oil again just so I knew it was good and clean. Sunday I started it again but it was very hard to start and have determined the electric choke doesn't work. Not at all like my Agility 125. Hence my previous post. Tonight when I got home from work I fired it up again. (hard to start, no electric choke) Let it idle for about 3 or 4 minutes and starting revving it up to 3 and 4 thousand rpm. Now keep in mind all the tupperware is off and I can see everything and I'm looking at the exhaust manifold and it is glowing orange hot. The temp gauge isn't even at normal operating temp yet and that pipe is glowing orange. I let off the throttle and let it idle again and the pipe went black. Finally the unit got to temp and a minute later the fan came on just like it always has in the past two days. I let it cool down, checked the plug and it was normal. If anything a little dark brown, so it's not running lean, right. So my question is, could this be normal. Has anyone seen anything like this before. I haven't. My air cooled Agility doesn't do this. What is going on? Help!!!!!!

[MaryK]

Googling "red hot exhaust pipes" yields the following causes:

1.  excessive idling
2.  Lean carb

So, I'd clean the carb, paying special attention to the choke passages (jets ?)which should help on starting and
may help on the RHEP problem.

The general rule is to idle the engine only until it gets warm enough to run without a choke.  That is why we haven't seen this problem.  The exhaust pipe gets air cooling as you ride.

Thank goodness that you have water cooling.... excessive idle time with an air-cooled engine is more destructive.

Sounds like you have a good scooter for little money, but you will have to spend time getting back into shape.

Clean the carbs again and use gas stabilizer: use Sea Foam which is both stabilizer and fuel system cleaner. 
After using 3 Tank-full, the fuel system should be cleaner... but don't use more than directed.

scoot safely,

[Portland Steve]

That is a liquid cooled engine right?
Is the fan coming on when you idle for so long?  Just curious, but the fan won't give enough cooling.
Don't let it idle for so long... a red hot pipe is normal especially if idled too long.