I've got an '06 and put the Thermo-Bob on. Have done some backwoods riding and a fair amount of first gear almost-trials riding for several miles and have worried about the engine temp but developed no real issues. The cooling system does like to be "movin' down road" The fan does come on and the temp will increase but have not overheated, though I don't like it getting that hot and I watch the gauge a lot. I guess I'll just have to buy another bike for the woods.(WOW!, what a brilliant idea!) The thermo-bob really helps stabilze the engine when temps are cooler. The thermostat in the thermo-bob kit is bigger than the stock so I would think when fully open allows greater coolant flow. I'm glad I have it.