Found a Sweet Engine, What Now?

I'm interested to hear how the EFI conversion works out and if it's a good option for high performance motorized bicycles. I'm planning to EFI an electromechanically injected auto in the near future for similar reasons, EFI is ultimately tunable with the click of a mouse and the stroke of a key. Changing carbie jets isn't so bad on a bike since its usually close within a step or two of running great, and you don't need an ECU power source, but for finely tuned bikes which run differently according to the weather conditions like a spastic two stroke, and could be rejetted every single ride because of temp and baro changes, I could see efi being a way to get the most out of your motor without having to retune the main jet every time you decide to rip.

Keep it up, sounds like a fun and reliable four stroke build. I recommend a rear brake just in case you gotta swerve and clamp it down in case of emergency, since a strong rear brake upsets the bike less when you need it most, and it's the first to wear out on all of my BMX's and mountain bikes that got shredded through the years.

Cheers!

Whatever you wind up with on the brakes, keep us posted. Just remember if you want more braking force with the same lever force, you need to reduce the master cylinder bore. Once you have the calipers set up, changing a master is the easy part.

I am running a 7" H4 light in a dietz style housing. Of course I have a lot of generator so running a 60w headlamp is no big deal.

I am running the two bulb stop / tail lamp with no problems. I have incandescent bulbs in it, and they hold up well.

Several people I know have killed a few LED replacement bulbs on motorcycles. Seems like vibration shakes the surface mount parts right off of the little circuit boards.

Most of that inexpensive LED stuff comes no where near the output of the original incandescent bulbs either. In a headlamp that is not as dangerous as a tail lamp or brake light. Your brake light should be clearly visible in full sun between 11am & 2pm from 300 feet away. The tail light should be visible from the same distance at sundown.

The final thing to consider is how the lights are powered. The pit bikes and some under 125cc street bikes powered the lights with AC power from the stator. This kept the lighting load off of the regulator & rectifier, and a bulb filament does not care AC or DC works. This also means that the lights are on anytime the engine is running - a very good idea.

LED replacements may not run on an AC circuit. Some run at half power. Probably best to get a wiring diagram for the motorcycle your engine came out of & see how the charging system / lighting system was connected.

My tail & head light run with the engine. My brake light runs off of the battery.

Hope that helps.

Looks like you got things pretty well planned out but here's a nice diagram I found on the jockey journal.

Although the fuses are in different places in the diagram, in reality they can be all in the same spot. I included a 4-slot fuse block in my build and a separate terminal block tucked inside the battery box.