Ok well I've been bike-less for a few months now since I sold my kx80s and traded my drz125 and my civic for a 1989 Toyota supra turbo fast fun car till I tore the tranny out. I got my first quad a 300ex but it stripped an output shaft and started smokeing so it's down till I rebuild it so i traded the supra even to a buddy for this 1999 cr125 He redone everything on the bike and the motor that came on it had a crack in the case where the swinger bolt goes through, along with a scared up top end. It had all factory red plastics on it, stock bars and wore out tires, he put pro taper bars and a 02 cr125 motor on it and a klihen carb on it, I believe it's a flat side carb but not positive. Along with other things, bike looks mint I got the bike and the 99 motor factory plastics, factory exhaust pro-circuit and fmf fatty and fmf shorty silencer that's on it now, So I've been reading and people say to put an 04 air boot on the 02 motor to open it up but that's on an 02 bike and I'm thinking this is the original 99 air boot so should I swap in the 04 or 05 boot? Air box already has a small hole in it witch I heard helps get air in as well, I also was wondering about case stuffing? The cr125 for this year was said to be one of the worst motors they built, and i can tell it compared to other 125s ive ridden, but this the first full size bike ive owned, would I get more power out of the 99 motor? I also want to add a headlight , I've been searching for a cheep solution but havent come across anything yet I used to have two bell bicycle handle bar lights on my DRZ they wernt the best but they worked, any input and info you guys can give me will be greatly appreciated, I'm pretty mechanically inclined but alot of this is new to me, I've only learned from what I've had to do on my own and modding cars an jeeps, I'm gonna probably do my first top end on the bike when I get back i town, my buddy did it about 8 months ago so it's probably about due. I really love the bike so far but I always like to improve things if I can and I figured you guys on here would help thanks in advance!