i'm no expert, and don't know your elevation,maybe someone else will chime in here,but I think you might be dumping to much fuel, search jetting on here.
Other than double checking the sprocket counts and jetting, air box lid or not, etc., I wouldn't believe there would be a noticable difference from pipe brands, I notice mine looses a ton of bottom end when the pipes need packed.
not a bad idea for you and your buddy to switch bikes and see what happens. Maybe he could tell the problem. But if he beats you on your bike, no problem.
pour a half a cap of oil in each cylinder thru the spark plug holes, that will tempoarily seal the rings so it will kick start. can also do a "wet" compression test that way.
Nice looking bike...makes me wanna go out and polish on mine. except for the "excessive heat warning" outside today.
Stock compression should read 125 w/throttle wide open kicking until the gauge doesn't climb any higher.
More important is both cylinder readings be close to each other.
'
Just earlier today I was trying to decide to part out my 2000 Banshee. my latest biggest expense was new Wiseco's and bore from F.A.S.T last november.
Less than 20 min ride time due to cracked flywheel, then noticed worn left crank bearing, explaining why jeff said the left cylinder needed bored 3 times over from the right.
Anyway, What i could get for the top end would decide whether or not to part it out.
The actual bearing number is 6007 2RD. THAT I have in my hand...sorry no seals, but they do have different I.D as stated above. My local NAPA quoted me $34.50 each for their 6007-2RSJ. Let me know how your store treats you.
I had the same type of emergency, my local NAPA had them, at $55 each. And I get a pretty deep discount rate. I sure hope your store can take better care of you.