To be able to keep a decent operating temperature in the engine while riding, I had completely covered the front of the radiator from the 2013 Polar Ice Ride R1, using three aluminium plates. In the middle, I used a solid 2 mm thick and 20 cm wide plate, which ran from top to bottom. I wanted to leave that one on, even after we reached warmer temperatures on the mainland. The reason was that I didn’t use a front fender and without that the chance of damaging the radiator by stones, thrown up by the front tyre, was very high. To the right and left of that solid plate other aluminium plates were mounted which had 1 mm thickness. In there I could make air breathers in case there would be a shortage on cooling. By bending the breathers further or less open, I would be able to control the cooling.
That was the idea, but it turned out totally different. Even after removing the two breather plates, at times the bike still had to deal with overheating! Yes, overheating at minus 30 Celsius! Mainly due to the wind direction. A tailwind meant overheating for sure and when having a crosswind it depended on the wind force, the outside temperature and my riding speed. If the bike stood parked while idling, it only got enough cooling when its nose pointed into a stiff wind. Headwind while riding however, made the engine cool too far down, which at the end will cause damage. Especially on the first camshaft which faces the cold wind. For this reason the 20 cm wide plate -covering a big part of the radiator- had to stay on its place in any case. But because the ventilator was positioned directly behind there, it couldn’t cool the engine enough if the wind came from a different direction.

What is the right way to do it?

On Arctic 1 two things need to be done totally different.
1st It may not have the radiator positioned straight behind the front wheel. This way the necessarily space will be created for the front wheel and a suspension with a long travel.
2nd The cooling should stay the same whatever the wind direction is. It also needs to be adjustable because of the huge outside temperature differences that we are going to face. -10°C until -50°C / +14°F until -58°F / 263.15K until 223.15K

The intention is to place two small radiators, just before the engine. One on the left and one on the right. They probably will be mounted in an angle or completely in line with the riding direction. By building an air chamber on each radiator, I can have the supply of cooling air entering from above. This way the wind force and direction no longer affect the cooling. Ventilators behind the radiators, which get controlled by a thermo-switch, regulate the intake and cooling. In case the outside temperature gets so low, that even without running ventilators the engine becomes too cold, I can temper the flow of cold air by a manual slide in the air inlet or even block the inlet partly with duct tape. Once this is all build and functional, I am going to look at a possible way to reuse the warmth that the ventilators extract from the radiators to heat my feet and/or knees and/or hands.