It's not that it's too lean. You will just have more top end power with a little larger main jet. With a 168 you can leave the airbox lid on. Tuning an engine is all about balance. When ever you increase the air flow you increase the fuel so there is something to burn. The things required for fire or combustion which creates an engines power are HEAT which is the spark, Oxygen which is the fresh air sucked in and fuel which in this case is gasoline. more air less fuel = lean, more fuel less air = rich the balance of the two is tuning. The pilot adjusts your bottom end the main is your top end and the clip on the needle is your mid which is kind a balance of the two. Take it in steps. What I find that works well is first of all everything stock (45 pilot 165 main stock needle untouched) lid on. High flow exhaust or baffle removed ( 45 pilot and 168-170 main needle untouched) lid off. High flowing exhaust W/K&n lid off (45 pilot 175 main needle on 5th or 6th) lots of power. High flow exhaust with cam mod, K&N intake (45 - 48 pilot 180 main with 6 on the clip) I did not see a big difference on the bottom between the two pilots it all depends how well you work the air screw on bottom of the carb. The 45 had a little more of a snap off the go which works well if I short shift into second which I usually do. The 48 works well If you want everything out of first but did bring my front end up a little to easy in the sand. Every thing works different for every one. It is a little frustrating but take some time and play with it, get to know your bike.
