[Metro61]

I own a venerable '73 Yamaha U7e scooter. It's extremely similar to the Honda Cub/Passport models, and is still in production (2-stroke and all) in Asia. It's a single-cylinder, 78cc. And it's pretty worn. I call it the Twenty-First Century Sex Machine.

I've already switched to a near-smokeless synthetic oil. But I feel I can do more. Inspired by the claimed successes of Orbital Technologies and their co-project with Envirofit, converting Bangkok tuk-tuks to Direct Injection, I've decided I'd like to come up with a conversion for the 21CSM.

I'm slightly ahead of the game, in that the 21CSM has oil injection within the crankcase, so I don't need to worry about how to lube the engine once the fuel is no longer entering with the air.

The general plan.
I want a returnless system. Add-on components will probably include:

1) Engine control module (possibly Microsquirt or similar)
2) Fuel pump
3) Fuel line--probably hydraulic flex-type--and filter.
4) Crank position sensor, possibly a Hall effect type running off a magnet tapped into the crank on the generator end.
5) Throttle body, possibly machined using the original carburation intake as a template, with Mass Air Flow sensor.
6) Throttle position sensor
7)Injector

I'd like to avoid having to add air injection, and I think I can.

Now for some questions:
First, has anyone out here tried this before?

Secondly, could someone advise me: For cleanest burn, the injector will need to fire the fuel into the chamber just as the piston ports are closed, which means it'll be shooting into a pressurized chamber. How do I determine how much pressure I need from the injector to acheive decent distribution of fuel in the chamber?

Thirdly, the fuel will need to be finely atomized upon entry. Without injecting an air charge, does anyone know of a way to do that? I read that the Aprilla system uses injectors with twelve or sixteen holes in. Anyone know what'll work?