What size jets should i run on my 300ex? I'm at sea level i have a k&n filter with no airbox lid , a supertrapp headpipe from an ids2 and a stock silencer with drilled baffels. What should i run for jet sizes?

 

Really theres probably no way to tell. Its just guess and check. Start out with something like a 140 main and work your way down.

 

heck, I'd just spend the $45 and get the k&n jet kit. it comes with instuctions on what jet to run with what mods. it tells you what needle settings to run, how much to adjust the air/fuel mixture screw.

yea, you could do it yourself with a days worth of trial and error, but how many jets are you going to have to buy to get it right? how many spark plugs are you going foul-out before you get it right?

 

I HAVE A FMF PIPE AND K&N FILTER I JETTED MINE UP TO A 128, I NEVER HAD A PROBLEM OR FOULED A PLUG, YOU CAN ALWAYS ADJUST YOUR MIXER SCREW, IT HAS BEEN A WHILE SINCE I DID THIS I THINK THE STOCK 300 HAS A 124 MAIN JET, I ON MY WAY TO HONDA NOW SO I WILL DOUBLE CHECK, CALL OR E-MAIL SUPER TRAP FMF HELPED ME ADJUST MINE

 

SORRY I HAD TO RUN OUT YES MY CARB IS JETTED TO 128 THAT IS WHAT FMF TOLD ME TO DO, NOW K&N TOLD ME 121 WHICH STOCK I WAS AT 124 SO THEY WERE WRONG. I HAD NO PROBLEMS NEVER FOULED A PLUG IT RUNS GREAT, INSTEAD OF TAKING YOUR AIR BOX LID OFF I PUT AIR FILTER PLUGS IN THEY WORK GOOD TO. GOOD LUCK

 

k&n uses a diffrent set of numbers, maybe thats why the number they gave sounded wrong. all I know is, I never had any experience tearing a carb apart or making any adjustments to it. and with the k&n jet kit I was able to install a pipe, and an outerwears air box lid, then nail the jetting on the first try. and the bike runs beautfully.