Motorcycle Repair: engine crankcase disassembly, engine crankcase, defective seals

Question
I just bought an old 1973 Suzuki TS250 two stroke motorcycle.  It runs but blows heavy blue smoke and the gear oil level is very low. The previous owner thought it was leaking gearcase oil into the crankcase/piston area.  I believe the crankshaft seal is leaking.  I have the entire engine completely disassembled except for splitting the gear case.  I need to split the gearcase in order to get to the crankshaft oil seal.  The book says you need a special tool model #09910-80113 to open the crankcase halves.  The tool costs $130 and I don't want to spend that amount for a one time use.  Can you offer a recommendation on how I can split the case without this tool.  I'm willing to try almost anything.  I don't have much into the bike so if I screw it up I'm not too worried.  
Thanks for you help.
Mike

Answer
Hi Mike,

Test the sealing properties of the crankcase before the tear-down. It may not even be necessary.

Perform a compression test and leak-down test. These tests pressurize the cylinder and crankcase and indicate condition of both. Leak-down test will find air escaping past defective seals.

Respectfully,
Mark Shively