The 1973 Yamaha MX line consisting of both a 250cc and 360cc model was Yamaha's first true response to the two year earlier entries to the serious "privateer Motocross racer" market made by both Suzuki and Honda.  Suzuki's TM line was the result of extensive race development by some of Europe's best riders.  Yamaha caught on fast and fielded Hakan Andersson and Van Velthoven on Yamaha works bikes on the 1972 European motocross Grand Prix circuit.  Hakan Andersson finished second overall in the 250cc class and Van Velthoven finished fifth overall in the 500cc class.  Both the 1973 MX250 and MX360 were genuine replicas of the 1972 works machines.  Yamaha was world 250cc motocross champion in 1973 with Hakan Andersson, while bikes entered by the French importer Sonauto won the national 125cc championship with Jallat riding and came second in the 500cc class, this time with Drobecq in the saddle.  Yamaha had genuinely arrived on the European world circuit and in mid 1974 introduced the newer YZ models that firmly placed Yamaha as a podium contender at every motocross event.  The MX360 represents a critical stepping stone in Yamaha's path to dominance in the sport.  The engineers at Yamaha critically studied the winning bikes of the time in 1971 as evidenced by the 360MX's wheel base being stretched out to match the current Maico 400's dimensions and the weight distribution and ground clearance being virtually identical to the Husky 400CR.  The 360MX utilized a ground breaking reed valve induction system that allowed for early intake of the fuel charge through the special windowed piston.  The reed prevents the fuel from backing up into the intake tract when crankcase pressure changes from negative to positive.  Consequently, monstrous ports and radical port timing were incorporated in the design without sacrificing low to medium rpm performance (something that Suzuki had not figured out with the "pipey" TM line).  They also incorporated a Capacitor Discharge Ignition system that was sealed in a polyurethane resin to protect it from water, corrosion, and vibration while delivering a consistent spark intensity and duration relatively independent of engine rpm.  All of this added up to a 360cc single that delivered 39 bhp at 7500 rpm while still allowing for a manageably wide power band.  One other trick item was the partial decompression mechanism that was interlocked with the kick crank.  The decompressor, located in the front portion of the cylinder, lessens compression, and thus reduces kick lever pressure to that of a mild 250cc, all automatically.

Automobile, Truck, and SUV Note: All of our cars, trucks, and SUVs are professionally detailed both inside and out. All of our cars and trucks receive a multi-point safety inspection and a fresh Mobil 1 full synthetic oil change, oil filter, air filter, and cabin filter service. Every car and truck sold, at Minnesota Motorcars, leaves our store with a full tank of gas and a road side emergency kit (which we hope that you will never need to use). Please visit our car store to experience our very relaxed and friendly approach to car sales and see just how easy and pleasant car buying can be.