I attended a motocross seminar today at North End Cycle in Elkhart, Indiana with my 2 sons. My one son is into motocross racing which is why we made the trip. They covered 2 stroke engine maintenance, 2 stroke lubrication, top end rebuilding, carb adjustments, how to replace your seat cover, just about everything. Even though it was aimed at motorcycle riders, I learned alot that could be applied to any atv. It took the better part of a day but it was free and they supplied pizza for the 50 people that attended.
Why I am mentioning this is not many atvers would think about attending a motocross clinic but if any are held in your area you might want to check it out especially if you are interested in working on your own machine.