It appears you're interested in specifications for the Yamaha Big Bear 400 4x4 IRS . This ATV model is powered by a Single cylinder, four-stroke engine with 386.00 ccm (23.55 cubic inches) of actual displacement before 8.6:1 compression. Fueling is metered via Carburettor. Mikuni 33mm BSR allowing this machine to produce its horsepower and torque. According to our records engine heat of the Yamaha Big Bear 400 4x4 IRS is moderated by Oil & air. You'll need to get familiar with the 5-speed transmission and pay attention to final drive Shaft drive (cardan) maintainence. Our best information shows that the front tire size is 25/8-12 and the rear is 25/10-12 . The entire package is supported by the frame, . We know you like to go fast or cruise all day, but when you need to stop, you'll be dependant on Double disc. Hydraulic front brakes and Sealed multidisc rear brakes. The Yamaha Big Bear 400 4x4 IRS was launched in 2012, 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.