I will start to add a little information about the 4-stroke Weber engine used in the Polaris MSX 110-150 series.

Changing the oil isn't difficult with the purchase of a few tools, and who says the dealer is any better at it than you?

I recommend a good oil filter socket, and a vacuum pump. I will attach links to them, but you can buy elsewhere also.. If you purchase the parts from me, free advice is always included!
http://www.watcon.com/Catalog_Pages/...il_Filters.htm

http://www.watcon.com/Catalog_Pages/Fluid_Evacuator.htm

http://www.watcon.com/Catalog_Pages/...ter_Socket.htm

Thanks for looking!
Randy