what kind of bike are we working on?? the avg temp for the elec fan to turn onis around the 220 mark. the best thing to do here is bench test the bike start it up and let it idle, put a fan that moves air in front of the bike, this will help to keep things cool while the bike heats up i know it kinda [email protected]
but do it. a inferred temp gun will help you get the temp, you can pick one up at your local auto parts store. check the temp near the senser for the fan and the radiator itself. keeping a GOOD
oil, clean oil in your bike that will help with the cooling as well. If your running a bike with a fuel filter ( If your not GET ONE ) make sure its clean. Bikes with fuel pump, you a two types in tank and external, your in tanks pumps should have a filter on them in the tank, over time they get clogged like a inline filter and can cause poor running as well.
If everything is working as it should you'll need to look into your coils. Heat causes resistance, resistance causes heat and heat causes wires to break down and contact points to to weaken. Coils take alot of abuse when it comes to electricity, it doesn't always happen but it does. coils go out and tire wear odd sometimes.
I hope this helps you out if you need any more help please feel free to contact me
Fix it right Ride it FAST