I recently added a K&N filter to my 300 EX and jetted the carb with a K&N dyno-jet kit. I followed the directions as listed then give it the old test drive.. Since then I have increased the jet size from a DJ 114 to DJ 120 and it is still running lean. I was wondering if I need to adjust the needle valve and see if that helps.. Also I am a newbie at this jetting so I am wondering which direction to move the needle vavle (my thinking says move from 4 notch to 3 notch). Will adjusting the air/fuel mix do my any justice? Right now with running the carb with a 120 jet on 4th notch the plug is a gray color, not white. I am needing some help here so any advice will be appreciated.

Dan

 

Where exactly does it cut out at? 1/3 2/3 or full throttle. IU gotta know this first to tell you what to adjust.

 

The engine is not cutting out at all.The problem is that it continues to run lean. I started with a 114 jet and now I am up to a 120 and it is still running on the lean side (the plug was grey in color after running it 3/4 throttle for about 1 mile). I am wondering if I need to change the needle position (go up or down) or just keep going up on the Jet size till I get the mix right. As the bike is now it has lots of power throughout without any missing problems... I am just trying to get the mix right.

Dan

 

As long as the plug isn't pure white and its grey I think you'll be alright.

 

You state you are running a 120 main, If I remember correctly, the stock main on a 330ex is a 120 with a 122 as the alternate, may want to check into that, unless you live in a high elevation area, then it would require a smaller jet than stock.


We also have a '97 300ex that my wife rides, and here is everything that I have done to it, and it runs excellent at sea level (the oregon dunes) and up to around 1000 ft. before jetting is needed again, jet smaller the higher the elevation, and bigger the lower the elevation.

-132 main jet
-needle in the center
-air/fuel screw (bottom of carb) 2.5 - 3 turns out
-K&N filter with outerwear and NO airbox lid
-Supertrapp IDS2 pipe and silencer.

 

Dyno-jet jets aren't comparable to Keihin jets. A 120 Dyno-jet jet, might be equal to a 132(example) Keihin jet. You can't always trust the spark plug.