side to the left, and then makes a 180° turn, returning to the right side and passing near the exhaust port. Most of the coolant is then routed to the very large radiator that sits across the frame in front of the bike. Some of the coolant that was not directed to the radiator is now sent around the inlet port and the left side housing. Its passage is once again reversed before flowing to the radiator. The water cooling is thermostatically controlled, and a shrouded fan on the right side of the radiator takes care of excessive temperatures, switching on at and cutting when the temperature falls below . Lubrication Internally the rotor is cooled and lubricated by engine sump oil and the aforementioned trochoid pump. Engine oil is filtered by an easily accessible car-type oil filter on the lower right side of the cases. The filter includes an internal bypass valve in case of blockage. Further lubrication specifically for the tip, corner and side seals is provided by oil from a tank located under the seat. An engine-driven metering pump sends oil from this external tank into the carburetor at a ratio of around 100:1. Metering of the oil quantity is mechanically controlled by cables from the throttle grip. The metering pump also provided lubrication for the final drive chain. A second line is routed from the metering pump and around the bike, ending just above the drive chain behind the sprocket cover. This feature was also disconnected on the "A" models by a simple blanking plug at the metering pump. The gearbox is separated from the engine sump and has its own oil supply. Suzuki marketed its own brand of rotary oil but also approved at least two other oils for use in its rotary engine. Shell Super 10-20-50 and Castrol GTX were both endorsed lubricants. Exhaust Rotary exhaust temperatures reach , and as such, on a motorcycle, required a specialized exhaust system. Suzuki dealt with the problem by first exhausting into a large, heavily finned manifold which split the single exhaust into two streams. They then built two twin-shelled exhaust pipes which included air cooling ducts. Each muffler contains a stainless steel inner pipe which is a little shorter than the length of the external shell. The internal pipe ends in a removable stinger drilled with numerous holes and wrapped in a fibreglass-like material. The stinger