I bought a 300EX and need some help.

[300EX'er]

Two weeks ago I got a 98 300EX. It's my first sport quad... I've always riden a 4X4. Its so much FUN! Now on to my question. The quad as an e series pro meg slip on, K&N air filter and jet kit.
The other day I tryed a plug test, it looked a little on the lean side to me. I know with additives in todays gas that plug readings are sometimes unrelyable, but im still conserned that it could be running lean.
What are some other signs to look for when watching for proper jetting? What size jets dose it sound like I should be running, and what size jets are with a K&N jet kit?

Thanks

[phatswinn]

125 or a 128 is probably what you should be running, check it as see, the plug test works unless u are running race gas, pump fuel doesent have the additives that would make the plug test not work, the plug should look a coffee color, any darker and you are running rich and any lighter means u are running lean, and allitle rioch probably isnt bad