My 07 KLX 250 had been sitting up for about a year after cleaning out the carb of the green dried stuff that clogged the jets and then cleaning it out a second time I finally got the bike so it would start and idle but I soon noticed the header pipe glowing when idling with the choke on. I pushed the choke in and the glow slowly went away. The next thing I did was to rev it to about 3K RPM and hold it and the glow came right back.Is this normal my other bikes have never done this I'm worried it will damage it's self so I have not run it since. Any advice would be great

 

Mine is jetted fine and if it idles the pipe will turn red, the smog stuff is still hooked up and that has alot to do with it I believe.

 

Mine is jetted. I can let it idle and don't notice the glow so much, but when I shut off the petcock and let her run out of fuel on idle, she glows. Leaning out when the bowl is running dry is what I think is happening. Did the same thing before the re-jet. Some time I'll open the petcock back up before it dies and see if it cools back down.

 

My SR500 with proper jetting had the single wall head pipe glowing orange on a sub-30 degree night when I let it sit to idle and warm up before riding home. Within a few seconds after riding, with some air flow, it wasn't glowing anymore. You have to figure the exhaust gas is in the plus 1000 degree range and if there's nothing cooling the exhaust it's gonna glow - even if jetting is right. It's just how bright and what color.

Odds are you are not doing any good letting the bike sit and idle in a garage or outside. It is better to just ride it. In addition, virtually zero warm up is really necessary as long as you don't go thrashing the engine instantly. If you can ride it with the choke on it is good to go.