Fitting an aftermarket speedo?

[Ted]

I own a Gilera Coguar... and as some of you may know... they were a moped company's (failed) attempt at a crusier!

So basically, everything breaks... apparently the speedos tend to break around every 6 months ...my one literally fell apart so I have decided to replace it with an aftermarket one.

I got ahold of one a while ago but haven't got around to fitting it yet. The fitting on the back of my original speedo isn't the same, is there just male and female connectors or would that be too simple?

also on the speedo it says '60mph=1000rpm' ...how do I work out what gearing to use?

Cheers people...