My ex is starting to get red pipes. When I start it and let it idle, no problem. But if I start opening the throttle alittle my headers turn a cherry red. The same problem happens when I'm actually riding it. When I ride it the headers turn red, but when I clutch it, the pipes return to normal color in a second.

What can be the problem?

Please help with any suggestions.

 

The carb is too lean.... richen the main jet. Try 160 or bigger?

 

It's got a 165 in it now. The spark plug looks good, but could it still be lean even with a gold/tan color plug?

 

So I should move up to a 170 or a 175 main jet?

 

So going to a bigger jet will help....yes...no???

 

If you don't have another main jet to try just lower the clip on the needle and see if that helps.

 

don't go to a bigger mainjet, your already too big. i would put in a 160 with the lid off and a 158 with the lid on.

lower the clip on your needle to the 4th position and your problem will get better.

 

Alright, we will lower the needle clip.

The jetting is about right the way it is now. I ran the 160 and it was way too lean. So I bumped his EX up to a 165 and it took away on sputters and misses, and makes it run perfect other then the headers. The needle clip is set one from the top, so I will drop it two or three positions, and experiment.

 

the needle should definately not be set at one from the top. it needs to be in the middle or one down from the middle (4th). this is probably why you have to run such a big mainjet. your showing a lean plug because of the needle clip location. i only run a 160 in the winter (cold air is more dense so use a bigger jet) on my 10.8:1 406, stage 2 cam, x-6 exhaust, uni filter, etc. i run alittle smaller in the summer.