Lol speaking of dirt bikes with slicks, I picked up this set two months ago to put on my Honda CR85 this year. The beautiful thing is as they are 17" I'll be able to run flat track tires on these as well so I can get dual usage.
When it's done it should look something like this, 85 2 stroke is all I need I've ridden a friends 450 flat tracker a few times and that scares the bejesus out of me. 250 is ok for a track that size in the video but the 150r is the fastest thing on kart tracks by far. 450 would really only benefit on a larger road race track.
These set ups can be done for reasonably cheap, especially if you already own the bike, I found these wheels, Excels for $400 with Sava slicks, big brake set up with the 450 caliper is under 300 and that is not manadtory, many run the stock set up like the bike in pic above, after that change out the springs for your weight again not mandatory and mount your slicks and you are good to go, pit bikes are even cheaper... The hardest part is finding the wheels. Which reminds me if anyone has a pit bike or Honda 150r that they want to convert to supermoto I have a supermoto new unused 12" set up for sale.
DUA Motorsports Bodywork, Akrapovic Moto2 exhaust w/ Akrapovic SS full system, Attack Rearsets, Bazzaz ZFI TC, Kawasaki Kit ECU, MWR race filter, Fren Tubo type 4 carbon fiber brake lines, Braketech Iron Axis rotors, , carbon Fiber clip on tubes, Renthal clip ons, ram air mod, Attack velocity stacks, Motion Pro quick turn throttle, Brembo 19x18 MC, custom carbon fiber subframe, Ohlins TTX36, Ohlins 30mm cartridge kit http://zx6r.com/pictures/26715-my-09-track-bike.html