Sponge Bob EFI Checklist

I guess I’m looking sort of seriously at doing this…

Parts required, big things first.

  1. Throttle Body – eBay purchase history doesn’t go back far enough for me to see what I paid for it, and I don’t have any pictures of it, but I have the throttle body from a big ATV, a Kawasaki if I recall correctly, with a bore very similar to the 30/31 PICT carburetor and more importantly, a similar horsepower rating to a stock 1600. This should make it pretty easy to adapt and install to the stock manifold, so…   check!
  2. EFI controller – I have the MicroSquirt version of the MegaSquirt II controller. The original plan was to exchange the MicroSquirt for the MSII on the Dragon Trike and use that unit for Sponge Bob. That may still be a good plan. The MicroSquirt is a smaller, weathertight controller with some motorsport friendly features, like built-in hardware for either two-coil wasted spark ignition or even coil-on-plug for four cylinders, etc…  check!
  3. Fuel system modifications – EFI requires a high pressure fuel pump, a regulator and return to the fuel tank. Motorcycles, with their really short distance from the tank to the engine, can generally get away with the pump, regulator and return all being inside the tank, with a single regulated high pressure fuel line going to the throttle body. Because of the way Sponge Bob’s fuel tank is mounted directly above the engine and carburetor, that would work pretty well here, too. The tank, however, would need quite a bit of work to make that work. It is currently just a plain cylindrical tank with a little tap on the bottom of it. The question becomes, do I figure a way to use it as is, modify it or replace it? Replacement becomes a decent option because places like Pacific Customs make fuel tanks to order.
  4. Rebuilt engine – Admittedly a rather big item, but I don’t think it’s wise to expend all the effort required to install and tune EFI on an engine that needs rebuilding. This engine should be properly in tune and running perfectly on a carburetor before the switch to EFI begins. The current engine has a freakin’ welded on crank pulley and keeps only most of its oil between changes.