I spent a couple hours on it today, and I am now grinning from ear to ear. It turns out that the 155 main was way too rich. I played around and now I have a 152.5 main, and the fuel screw 2.5 turns from tight, and it runs alot cleaner, much less smoke. Man does this thing pull hard! It is very nice to work on becuas it is very responsive to changes, and I can immediatly tell if it improved or not. I am still thinking about trying the stock 150 main, I think I could get away with it just fine. A mechanic up at my dealer told me that a couple people with that pipe have been running stock jets without a problem. I haven't done anything with the needle, because Im not too familiar with that. I guess I might have to play with it some day when I have time. Right now this thing pulls so hard. First gear is nuts, you can't hit the throttle without pulling the front end right up. I am 180 lbs and I can lean forward, and pull a wheelie with just the push of the throttle. Even second gear can pull them up without any effort.
I had it up by my dealer today driving it around, and all the mechanics and 2 salesman had to take there turns riding it. They were extremely impressed. THey couldn't believe the power gain. The pipe says 5 HP, but feels more like 10. Pretty soon they are gonna have there dyno set up for 4 wheelers too. One of the guys has almost 1000 dolars stuck into his KFX 400, which he uses for oval racing, and he said he thinks mine pulls harder. And I only spent 270 on a pipe and a K & N filter.
If you haven't noticed, I AM PUMPED!

 

Oh yeah, I was going to mention, if you are running a K & N filter, do like it says and make sure you take out the foam pad. At first I didn't read the directions, and I left the foam pad in there, and my top end kept choaking off like I was hitting the rev limiter or something, then I took that pad out, and then it pulled hard and clean straight through until the rev limiter.

 

Im at about sea level and I had to go all the way to a 167.5 mj and a 50 pj. Ran like a raped ape!