I have a 03 raptor with a new yosh. full exhaust system and a K&N filter and jet kit with 2 holes in filter lid....My question is this...I went riding today and its was about 40 degrees out....Bike runs awesome no back firing nothing.... I did a wide open run and shut bike off and checked plug after about an hr. of riding....IT WAS WHITE...(LEAN)... So i took it back to the truck and back to the dealer who installed everything....they pulled plug and it was a normal brown after my trip back to the truck....???? They told me due to the cold that the bike might be running a bit lean.. As i stated earlier.. atv is running great...no back fire nothing....One thing they noticed at the shop and i did too was a puff of black smoke on a shot of throttle...which means rich...So...should i ride it again and check it when it warms up....I would really like some help on this guys....and thanks alot...

 

Did they tell you what mains, what pilot and where the clip is on the needle? There is alot of advice floating around this forum given the full scoop. Smoke off idle could be rich pilot. Maybe lean down your idle mixture screws a little. If you did a plug read at WOT and shut it down, that is when it should be read, not after it is idled onto a trailer. If you have to, do a plug burn and then pull that plug out, install another one to load and take the one you did the burn on back to the dealer to let them read it.

 

yOU DEFINENTLY NEED TO SEE WHAT JETS YOU HAVE IN. wHATS YOUR ELEVATION, AIR DENSITY. I HAVE AN 03 LE RAP, W./ FULL YOSH, 20 OVER STOCK JETS,, BIG HOLE IN AIR BOX. RUNS A LITTLE RICH, BUT ALL IN ALL RUNS GOOD. NO POPPING, BACK FIRE OR STALING. DEFINANTLY FEEDS THE MONSTER FROM BOTTOM TO TOP.

LOTS OF THINGS CAN PLAY INTO THIS, AND THE SPARK PLUG COLOR ON A FOUR STROKE IS ALOT DIFFERENT FROM A 2 STROKE.

 

What jet kit do u got?

 

the jet kit i got was a K&N jet kit with the filter.....I did the Wide open run and then shut it off....thats when plug was white....The dealer also said with a 4stroke it would fair with temp and altitude...but does this mean everytime i leave Ofallon IL and go to MO.. I have to change jets....???

But thank you guys alot....im new at this and all the advice is great...Thanks