I slowly cut away with a 6 inch cutoff wheel on a hand held grinder, start working your way closer to the main part of he crankcase with the obvious ...it makes the rest go easier, when you get to within about 3/4 of a inch to the main case it would be a good idea to separate the case halfves to see how far to go before you break into the case. There are two places on the 041 that are hard to tell if it's ok to trim away, one of those places is on the back by a double layered part of the casting.... it seems like it would be ok to trim away there but it's not, it'll open up into the case. I tried to use a hacksaw at first , no way, 6 inch grinder makes quick work of it. It works so well you can afford to go very slowly with the trimming. With you have it taken apart as much as you can without cutting, start by cutting all the way around the case parallel with the crankshaft about 1 1/2 inches away from the round part of the case on the tank part of the case. It will just start falling away with the help of a screwdriver after you make four parallel cuts. hope this helps