This is to let some of you people know that extremely hot weather can affect your motorcycles almost the same as extremely cold weather can affect cars.
In over 20 years of motorcycle repair, I've seen extremely hot weather induce low speed/idle problems in motorcycles due to the following reasons:
-fuel boiling or vapourizing in fuel system due to idling in hot traffic (symptoms similar to fuel freezing) bike feels like its running out of gas.
-batteries failing to provide enough current (usually battery is 2+years old). Charging systems can have problems in extreme heat as they do in extreme cold.
-cooling system not maintained properly. Weak coolant causes pump problems such as leakage or overheating (this contributes to fan possibly running too much, possibly taxing the charging system).
-problems starting motorcycle when engine is hot - weak battery or lean fuel setting.
Keep in mind that fuel is made of components that are very active when heated which in itself can cause running problems in these conditions, especially if you should get a tank of lousy fuel or let the bike sit for more than a couple of weeks in weather that accelerates evaporation.