If 2002 or 2003 they had a recall on them and yamaha has a heat kit.
www.grizzlyowners.com/66-general/23-grizzly-recall.htmlIf not you can probably still get some ideas from the recall.
Ethanol gas makes engines run hotter. If you can find it just use pure gas. That can be good for 15 to 30 degrees alone in a smaller engine. A fuel tank insulator could just be the high heat under hood type insulator that has a foil face to it. This could be used on the fuel line over some pipe insulation as well. A heat shield could be made to go over the top of the motor with the insulation on it as well. Mine is just a piece of aluminum roofing.
If your model has the fake vents above the radiator in the front they can be cut out to allow airflow to hit the heads and keep hot air flushed out better from rising up to the carb and fuel tank. Cleaning the finned portion of your head with an aluminum polish and getting the oxidation off will also help a little.
Not knocking anyone's oppinion but I would stay away from the header wrap if you worry about rust. On my street rods I powder coat the header, wrap them and seal the outside. Even though they don't stay out in the weather they still rust over time. They don't cross creeks or get water slung on them all the time or mud caked to them to hold moisture. Just the good Ol' AL humidity does it. The wrap is perfect for wicking humidity to the steel. I think that maybe the natural process of cold wanting to go to hot accelerates the humidity sucked into the wrap when the headers are just about cooled off.
I do run wrap on the pipe and it is very rusty. Every year I take it off, paint it and the muffler and reapply. I don't ever try to get the rust off because I figure good metal will go with the bad and it will be sooner that I'll have to repair the pipe. I've had it on 10 years and haven't had to patch the pipe yet. Mine is the smaller kodiak. My problem was it would burn your legs on a hot summer day if you were just tooling around. The main jet in my carb had 3 slots that an e clip goes into to adjust your off idle mixture to about 1/2 throttle. I moved it from the top position to the bottom to increase the amount of fuel on the low end making it richer and in turn cooler. It also gave a little more umph off the line to power the big tires in mud as well as yanking on logs to get them started for skidding. I also have the idle adjusted a little rich since low speed and idle was where your legs would start burning through the covers. I insulated them a little better as well.
