I've done several and it's a fairly common job on Harley's that are being customized. The usual brand is Dakota Digital but they are expensive. I'm sure there are other brands out there but off hand I can't think of any names.
The usual method is to run the electronic tach off of the ignition circuit that operates the coils. Every time the coil fires on a single cylinder engine with a single fire ignition, for example, that's 2 revolutions of the engine, and the unit itself will convert that to RPM. The trick will be finding a unit that is set up for your bike's ignition, or can be set up for it.
You might want to call JP Cycles metric tech line and see if they can suggest a unit that would work on your bike.
The usual method is to run the electronic tach off of the ignition circuit that operates the coils. Every time the coil fires on a single cylinder engine with a single fire ignition, for example, that's 2 revolutions of the engine, and the unit itself will convert that to RPM. The trick will be finding a unit that is set up for your bike's ignition, or can be set up for it.
You might want to call JP Cycles metric tech line and see if they can suggest a unit that would work on your bike.