is it the split next to the oil drain plug? if it is than your looking at a complete engine teardown. Not the worst thing, just plan on replacing things on the way such as bearings, oil seals, and nething else that might be trashed that you can get at since you have the engine completely ripped apart. A tube of yamabond costs about $7.00 from your Yamaha dealer, the tube should last you for about 3 engines. Also your gonna have to buy a new complete gasket kit for about $40-$60 (unsure of the price), trust me you will destroy half the gaskets and need new ones and its cheaper to buy the whole kit instead of individual gaskets. Personally I put Yamabond on every mating surface and gasket I can, ensuring no leaks. Clean the gasket surface with acetone, it works great. And a service manual will be your bible for the next couple of nights/weeks that it takes you to tear down and reasemble. Also you'll need to invest/ find speciallty tools that your manual calls for ie: torque wrenches(alot of times your local dealership will have them and for $5 they'll do jobs such as pulling off your stator and spliting the cases for you. And be extremely carefull with all hardware used on any Yamaha engine. They suck. Many of the bolts, philips head screws, will shear right off or strip. Follow your manual to the T, engine work is not as bad as it sounds, my first engine I was scared to take apart, but after building it twice I felt I could do it blind folded. Ask alot of questions and the process should be simple, I'll try to help as much as I can.
