OK so I'm trying to find a way to better cool my Yamaha bruin 250. It has no oil cooler but it did have a set of fans on it right in front of the header that were broke since I bought it and I just threw them out but I could not find anything about the bruin having any fans stock.I have not had many problems with over heating over the past year I've owned it but any time I went riding without stopping for almost 2 hours I would have to stop and let it cool for atleast 15 minutes and it would also loose some power and since I usually ride with another person on back and have about 50+ pounds of gear on it I need all the power I can get out of it and I'm sure that extra weight adds to the over heating. So any suggestions on what I can do to cool it better than just the fins like are they're any fans I can fit on it or is there some oil cooling kit like the recons have.And just wondering but how hot does the crankcase get on these air cooled motors get specifically in the flywheel/starter clutch area.Thanks in advance

 

You could put some more electric fans back on it. Also check your jetting to make sure it's not running on the lean side. If you richen the mixture up some it will run a little cooler.

 

Are your Fins clean/cleared of baked mud? My old 1987 Yamaha 250 Moto4 had no oil cooler or fans yet it never over heated even on my heavily loaded down fishing trips on the hottest days.

You can try a better grade oil for heat. Synthetic oil can put up to more heat to then conventional and also move to a higher grade heat range like 40 or 50 weight vs 30.

 

Sounds like you kinda answered your own question, you're overworking the poor machine. I would 2nd the synthetic oil suggestion. Riding an air-cooled machine for long periods at low speeds will cause them to overheat too. You just don't get much air to the engine to cool it off. Moving at speed helps force more air in to help cool it. I've noticed in many liquid cooled machines that as soon as you stop them and let them idle, the fan has to kick on to keep them cool. While they were moving, the engine was getting enough air that the fan didn't have to turn on.