Arduino Goped / pocket bike / 5th scale R/C ECU

yep i bet this questions been hit a thousand times in the past but with the dawn on Arm based Arduino's i think it has more then a fighting chance

this projects goal is simple
computerize a simple single cylinder or v twin engines
taking over 3 things

  1. throttle yep drive by wire (helps with air control)
  2. Fuel (simple 30~40psi on a high impedance injector)
  3. Spark

sensors to be used
Math
Map
TPS
RPM
Maybe o2 but not in the works yet

i have a full shop
2X repraps, CnC machine,and tools list runs on, and more then i need as far as parts and sensors go.
this is not my first venture in to micro-controllers.
3X hexpods, 2X UAV's and my self driving, 3d mapping kinect rover that can kick Pi's FPU's
with it's intel Core i7 2600K oc'd to 4.6ghz(real time full color 3D mapping with 3 xbox kinect's eats cpu power more then you know)
mind you all i'm much better with C#, java, python, then MCU's and hardware.

just need some ideas to get me going.

First project will be my mini chopper it's 230cc 4 stroke V twin with RHB31 Turbo
i want to try and used maybe one of my JR mini servos as they rock for throttle but might use a feedback loop with a pot and steeper for safety.
i CnC'd a fuel pump for it about year ago still going strong reg set to 25psi tested to 140psi at 1270cc/min peek

Crank position sensing is going to be the hardest part of the problem, and if you can arrange to use a trigger wheel that would be the easiest way to get an accurate signal. Otherwise you're going to be guessing the RPM and extrapolating the crank position, and that's going to make it much harder to fire at cranking speeds.

Have you considered a Megasquirt based solution, and optionally EDIS for spark? That sorts out a lot of the hardware design for you and also gives the the front end and mapping software.