actually, ive done it once, but it was tricky... you can take one side off, the stator side off without taking everything out of the clutch side. It is more difficult to get everything aligned again, but if you have 30 minutes extra it should be fine.you need to undo all the bolts that hold the cases together, take off the stator, the chain wheel (drive sprocket) and the cylinder of course, then, with the pulling tool, you will be able to pull the stator side case off. PS: this is also only if you dont need to change any bearings, including the crankshaft bearing. Remember to grease up the inside of the crank seal when ur puttin it all back together, or alternatively, install the seal once the cases are closed.