I've been having some trouble with my 02 Trailboss here lately and hopefully someone can help. I hadn't rode it for 3 or 4 months because the tranny was out on my truck and I had no way to haul it. So, I fixed my truck and got it out and the oil cooler fan, that had never came on since I owned the quad, suddenly runs constantly. Well, I'm thinking, maybe it wasn't working right to begin with. After all, an oil cooler fan should come on at least once in a while, right? Well, ther next time I get it out, (a couple of weeks later) the fan comes on as soon as I turn the key over. I knew right then that something wasnt right, but I figured it could hurt for it to run so I went riding. After about an hour or so of riding, the temp light comes on and I know darn good and weel the thing isn't hot, but in the back of my mind I was a little worried because I did put an Aaen muffler on late last summer. I went up 2 sizes on the main,but I wasn't sure if it was jetted perfectly. I'm hoping thet there is a temp sensor that runs both the fan and the light, because if there is, then I know what my problem is. Oh, by the way, when the temp light came on, I parked it for at least 45 minutes, and when I started it up, yeah, then fan came on, and probably 30 seconds later the temp light came on too. Ther's no way that thing could heat up that fast, right? .... And yes, the whole time it was running great.

 

don't know much about bosses but if its water cooled its a good bet to check the coolant level same thing with oil levels

 

Your water pump may be going. No circulation of water in and around the boe will cause an immediate overheat within minutes.

 

How long has it been since you changed the oil?It sounds more like a faulty sending unit .You have an air cooled motor not liquid cooled.

 

the boss is air cooled. the fan is an assist for the oil cooler. wish i could help more, but haven't had anything like that on mine.