I searched the forum and web and it got more confusing the more I looked. Anyway, when I purchased my DR400s the previous owner gave me a couple extra sprockets. It currently has a 45 tooth installed. I also have an extra 45 tooth as well as a 41 tooth sprocket. It seems to me that there is quite a gap between a 41 and 45 tooth sprocket. I've mostly seen 44 tooth sprockets listed for the DR400s on my searches. Does it seem odd that the DR would come with two sprockets so widely spaced? Any reasoning for the combination of 45 and 41? I would also think that changing a sprocket back and forth would be a pain in the butt! My DR has about every mod possible. So, it's pretty much maxed out for the stock motor if that makes a difference. I would also say 90% of my riding is Forrest trails and the other is 60mph side roads. My riding partner has a DR200se. So, getting these 2 bikes synced is high on the priority list! Runny off and leaving my partner (the wife) would be very, very bad. Most, if not all my riding is done with my wife. Sorry for the Noob questions. But, I figured someone here is running a similar combo.