IMS added exactly one gallon of capacity to the Yamaha's meager stock fuel supply, where the buzz-killing low-fuel light routinely lit up after 75 miles of silliness. To carry 128 more ounces of unleaded, the IMS tank is 5.5 in. wider at its girthiest point, 5 in. longer and almost 2 in. taller than stock. This greater capacity creates tighter tolerances between the radiators and the tank and a negligibly taller profile than stock. The IMS item does away with the WR's locking fuel cap and its narrow fuel-fill opening, coming with a plastic, screw-on cap and a tremendous mouth, making fill-ups a much simpler affair.
From the saddle, whether sitting at a stoplight or carving apexes, there's no noticeable difference with the big tank in place. This makes us wonder why Yamaha let the aftermarket increase the WR's fuel capacity to acceptable capacity instead of equipping it with a bigger tank—and this is the greatest compliment we can pay IMS's aftermarket ingenuity.
With a capacity that should have come stock, this aftermarket tank is a simple mod that's easy to install which doesn't create any comfort or mechanical issues.