The climb to Song Kul lake was to be our highest yet. We were a bit anxious as we have experienced problems with the troopy overheating at altitude on big climbs. I decided at this point that it would be a good idea to adjust the fuel mixture for the lack of oxygen at higher altitudes. The thinner air causes the fuel to burn hotter and overheat the engine. We traveled a couple of hundred km from Issyk Kul lake on good paved roads before we turned off and hit the gravel preparing for our climb to Song Kul. We were at almost 2000m above sea level before we started the climb. When we got to the foot of the mountains and could see the track Zigzaging it’s way steeply across the mountain face, we knew that we would be having problems. Turned out we needed to stop 3 times to allow the troopy to cool down.