Re: number of poles,tach install on Force 85?
Pole setting or pulse setting? I did come across a tach once that was set to a 12 pole or 20 pole alternator by a switch on the back. Most tachs ask for a PULSE setting. the switch will be marked something like 1, 2, 4, 6. These tachs will NOT work with the 20 pole alternator that your engine has.
You can get a Tiny Tach which while not as pretty will work off the top plug wire. Search the forum posts for "Tiny Tach" to read about them.