Just drill and tap the crankshaft for a 7/16-20 bolt and use a balancer installation tool. Most FLAPS will rent you one. I used to make a fixture to center the drill bit and tap accurately and install balancers, until it became obvious that most people couldn't follow the simple printed instructions I provided with the kit.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!