were intended to feature new colors, a redesigned logo, and possibly keyed ignition, these models were virtually identical to the ‘86 offering. Though sold concurrently, the Honda TRX250R would remain in the Honda line-up until 1989, effectively becoming the ATC's successor. The four-wheeler used many of the same components as the ATC250R, including a slightly detuned version of the ATC's engine. Competitive Racing Honda created the ATC250R as a consumer sport ATV, but would offer multiple variations to their factory racing teams in the 1980s. These machines were designed for several displacement classes. The ATC125R, ATC200R, ATC300R, ATC350R, ATC400R, ATC480R, and ATC500R were all tested at various times during ATC production. The Honda ATC250R's competition came largely from the Kawasaki KXT Tecate 250 and Yamaha Tri-Z 250, and to a smaller extent from companies such as Tiger ATV. From in-house, the ATC250R is often compared to the Honda ATC350X, a sport ATC featuring a 350cc 4-stroke engine. The ATC350X was not competitive on professional circuits, and was better suited to amateur racing and recreational riding. Engine Specifications Engine type - Water-cooled 1985–1986, 2-stroke, single-cylinder Bore & Stroke - 66 x 72 mm Displacement - 248 cc for 1981-1984 or 246 cc for 1985 and 1986 Compression ratio - 8.0 to 1 Lubrication - fuel:oil mixture Air filtration - foam element Cylinder Bore - 66.020 - 66.040 Piston/cylinder clearance - 0.060 - 0.080 Piston Diameter - 65.94 - 65.96 mm Pison pin bore - 18.007 - 18.013 mm Piston pin outer diameter - 17.994 - 18.000 mm Piston-to-piston pin clearance - .007 - .019 mm Piston rings per piston compression - 2 Ring end gap - .20 - .40 mm Ring side clearance - .045 - .075 mm Connecting rod (sm end inner diameter) - 21.997 - 22.009 mm References Honda ATVs Vehicles introduced in 1981