Manual - Chapter 4 - Cooling

4. Cooling system: filling

  1. Before filling the system, always check that the drain plug has been fitted and tightened and that the hose clips are tight.
  2. The recommended coolant to be used in the system is made up of 40% corrosion-inhibited ethylene-glycol antifreeze suitable for use in aluminium engines and 60% distilled water; this gives protection against the coolant freezing in temperatures of down to - 28°C ( -18°F). An alternative mixture ratio of the same ingredients for lower temperatures is listed in the Specifications Section of this Chapter. To give adequate protection against wind chili factor and other variables, the coolant should always be prepared for temperatures - 5°C (-9°F) lower than the lowest anticipated.
  3. Use only good quality antifreeze of the type specified; never use alcohol-based antifreeze. In view of the small quantities necessary it is recommended that distilled water is used at all times. Against its extra cost can be set the fact that it will keep the system much cleaner and save the time and effort spent flushing the system that would otherwise be necessary. Tap water that is known to be soft, or rainwater caught in a non-metallic container and filtered before use, may be used in cases of real emergency only. Never use hard tap water; the risk of scale building up is too great.
  4. So that a reserve is left for subsequent topping-up, make up approximately 3.5 litres (3.7 US qt/6.2 lmp pint) of coolant in a clean container. At the standard recommended mixture strength this will mean adding 2.1 litres (2.2 US qt/3.7 lmp pint) of distilled water to 1.4 litres (1.5 US qt/2.5 lmp pint) of antifreeze; do not forget to alter the ratio if lower temperatures are expected.
  5. Having checked the system as described in the subsequent Sections of this Chapter, add the new coolant via the radiator filler neck. Pour the coolant in slowly to reduce the amount of air which will be trapped; then the level is up to the base of the filler neck, fill the expansion tank to its upper level line. Refit the expansion tank filler cap.
  6. Start the engine and allow it to idle until it has warmed up to normal operating temperature, with the temperature gauge needle (where fitted) giving its usual reading; the level in the radiator will drop as the coolant is distributed and the trapped air expelled. Add coolant as necessary. As soon as the thermostat opens, revealed by the sudden steady flow of coolant across the radiator and by a warm top hose, the level will drop again and more air will be expelled in the form of bubbles.
  7. All trapped air must be expelled trom the system before the radiator cap is refitted. When the level has stabilised for some time with the engine fully warmed up, and there are no more signs of air bubbles appearing, top the level up to the base of the filler neck and refit the radiator cap. Stop the engine, check that the expansion tank is topped-up to its upper level mark and refit the radiator shrouds, fairing components and side panels.
  8. When the machine has been ridden for the first time after renewing the coolant and has cooled down, check the level again at the radiator cap to ensure that no further pockets of air have been expelled; top up if necessary. At all other times the coolant level should be checked at the expansion tank, as described in Routine Maintenance - Check the coolant level.

4.5 Refill cooling system at radiator filler after draining...

...and top up at expansion tank afterwards