I just put a new slipon on my 03 kfx 400 .I rejeted it for my altitude( less than 1000ft) 150 main new needle 3rd position as per instructions. I went out on the ice with it and noticed that the head pipe was glowing red! Upon further examination I noticed that I could get it almost bright red just idling. The thing really runs nice, I only took it out for maybe 5minutes and shut it down . I am also running a k&n filter an outer skin and no airbox cover. I am not sure if this is normal or not, it sure seams strange that it runs so cleanly through the whole rpm rangr, no ticking missing or anything. Anybody have any ideas?

 

Put the stock airbox lid back on and see if it gets better.....if it does get better you are lean without it and need to jet up higher.

 

when you say jet up higher does that mean a larger main jet and a larger pilot jet? How much of an effect does temperature have? I will however put the lid back on and see what happens.

 

Really sounds like you need bigger jets.And like pjr989 said you may need to go up on both jets if it does that just ideling.I havent jetted many 4-strokes but 2-strokes run really good if their a little lean but its not good for them.

 

The instructions may have been for summer jetting versus winter. You may need a bigger main.

 

I called the dealer today and he told me that 4stroke exhausts do actually get that hot and the only reason I noticed the colour was because I was riding at night. JUst to be safe I am going to up the main from a 150 to the 165 that was supplied in the dynojet kit I think I may also lower the needle a position wich would put it in the 4th from the top.comments?

 

Probably need to lower the clip on the needle which means your raising the needle.Your needing more fuel so the needle needs raised not lowered.

 

Some exhausts do glow red and thats that...like my ds my jetting is spot on as it could possibly be and she still glows. Get a temp guage its a good investment.

 

i had mine glowing for a little bit when i was jetting my quad, like 6 inches of the headerpipe was glowing and it ruined the chrome finish (looks foggy), in this piece of paper i have from biggun it says if exhaust temp exceeds 1300 degrees then it will ruin the finish


now she doesnt glow anymore, but i havnt got on a hard ride though...its too damn cold -25 celcuis today [img]i/expressions/face-icon-small-sad.gif[/img]

 

anything over -20c and you need a snowmobile lol or just freeze ur *** off on a quad.