I put a DG full exhaust on my 01 raptor along with a K&N filter. I went riding last night first time and the header pipes were glowing bright orange. I figured it was running lean so i put the stock air filter back on ... header still glows, even at idle. ... Is this normal with aftermarket systems or will i need to jet the carbs? (riding conditions were about 40 degrees) ... I dont want to jet it if i dont have to.

 

If you put a full exhaust on it, you need to jet it. Putting the airbox on isn't going to help, because the carbs still aren't jetted to match the new exhaust or the new intake. You are correct in the glowing being a lean condition, after market pipes are more prone to glowing also because they are thinner metal than stock exhaust. A rejet is still a must, though.

 

will lean cause damage to the engine or can i ride with glowing pipes ...

 

It could potentially cause you big problems, yes. Not only that, it's likely the bike will actually be slower with the new exhaust on since it isn't getting the right amount of air/fuel. You really need to jet it. Visit the raptor forums Yamaha Raptor Forums lots of information over there. They will be able to set you up with exactly how to rejet it. Good people over there.

 

Yea you should get a jet kit... I can light ciggs off the headers of pretty much all 4 stroke bikes and yea they glow red, but not at idle unless just ridden... You can only really tell at night.

 

Yes you should get a jet kit befor you ride it again your pilot and main seem to be very lean. By richening up your jetting your motor will have more power and run cooler.