It appears you're interested in specifications for the ATK 604 MX. This Cross / motocross model is powered by a Single cylinder, four-stroke engine with 562.00 ccm (34.29 cubic inches) of actual displacement before 9.8:1 compression. Fueling is metered via Carburettor. Mikuni TM 38 Flat Slide allowing this machine to produce its 40.00 HP (29.2 kW) horsepower and torque. According to our records engine heat of the ATK 604 MX is moderated by Air. You'll need to get familiar with the 5-speed transmission and pay attention to final drive Chain maintainence. Our best information shows that the front tire size is 80/100-21 and the rear is 120/90-18 . The entire package is supported by the frame, Nickel-Plated-Heat-Treated-Chromoly. We know you like to go fast or cruise all day, but when you need to stop, you'll be dependant on Single disc. 2-piston calipers front brakes and Single disc. Disk mounted on front-sprocket . 1 piston caliper rear brakes. The ATK 604 MX was launched in 1991, and we're happy to know (or assume) you've got one in your garage. To help you keep your ride in tip-top shape, consider purchasing an owner or service manual.