splitting a case

I got this 2007 Honda PO250S in my garage that im working on. The timing chain fell off the bottom sprocket, thats what i get for having little kids messing around the bike while i work. Is there anyway of getting it back on there with out splitting the case, if not how do i split it without a splitter and when its still on the bike. I need to get behind the flywheel.
 
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