Full mod Pit Bike

I have a full mod pit bike I’d love to put one these on and test it out I hate having to tune the carb often here in Minnesota where the weather changes frequently much simpler to just plug in a laptop or even have auto tune. Do you know when beta will go out? Do you know if the fuel injector fuel pump and throttle body would potentially be able to handle e85? Finally, do you have any idea roughly of what one of these systems would cost?


If you twist my arm, I’d say mid-summer right now. There’s still a lot to get done before we’ll be ready to roll.

Good question. I haven’t done anything with E85 yet. I probably won’t be able to until after beta release unless a bunch of people ask for it.

Still on target for $199 for the conversion kit (not just the ECU). ECU, TB w/ TMAP & TPS, pump, injector, lines, harness w/ American wire, and assorted hardware. One of the biggest challenges has been keeping the price super low while not skimping on quality or the more advanced stuff.

I would love to test one of these kits on my pitbike if your interested just let me know I have used some tuning software before specifically hondata s300 on my car so I have some knowledge on efi and tuning.

Thanks Aaron! And welcome aboard by the way :wave: What’s the make/model of your pit bike?

2007 Crf50 frame pisterpro 155cc engine with tb 184cc big bore tb v2 race head with roller rockers and takegawa s35 cam. Lots of other goodies

Sweet! Got any pictures? Let’s see it :+1:

We’ll need to figure out the electrical capacity at idle, and the trigger style too. Got any technical docs like a service manual for the engine I can take a look at?

Here it is. It has a signal magnet trigger. I will have to get a rectifier to convert the ac output of the lighting coil to DC for battery to test current at idle. Would there be anyway to make a battery less system like the newer big bikes?

Looks great!

Sounds good, let me know if you need any help with the testing setup.

That’s a good question, it’s been requested before but I’m not personally familiar with battery-less operation or the details involved. Interested in taking point on research for this? I’ll take a look at any info you find, and see if it’s feasible on the system. Or what it’ll take to adapt. :+1:

About how many amps will the efi system need to function? What is the voltage range the the ECU and fuel pump can handle because I’m assuming at idle the voltage will be slightly lower than at high rpms. I am currently on the search for a full wave rectifier instead of a half wave one because I hear the full wave ones are alot more efficient and produce more power. I can look into a battery less system in my free time but from my understanding is that they use a capacitor to store some power just to prime the fuel pump and power the ECU on when starting the bike then once it is started the stator takes over and powers everything else.


For now the number I’m going with is 5 amps to be conservative. I have a pressure regulation strategy in mind that should bring the requirements of the pump down a good bit. But that needs implementing and testing. For now, let’s go with 5A.

Yes, definitely full-wave. I can recommend a suitable rectifier that won’t be overkill or break the bank. Got any technical docs like a service manual for the engine? They usually have a decent diagram and specs for the stator that would be helpful

I can’t say for sure at the moment, I haven’t tested for low voltage scenarios yet. I’ll have to get back to you on this.

Unfortunately these engines do not have any service manuals that I know of the stator has 5 wires coming out of it 2 go to the trigger blue one and green one. two yellow wires come out of the lighting coil and there is a black wire which I assume is a ground. If you could find me a full wave rectifier/regulator that would be great

I misspoke the black wire is actually black and red and runs to the cdi I don’t know exactly what it does maybe you do?

Hey Aaron, I’ve been looking into this. Judging by your description and what I can gather, here are my thoughts.

The two yellow wires from your stator are going to be your charging winding, apparently it has no center tap which is fine. Based on that I would recommend trying this rectifier first:

This is how I’d wire it to test things out:

  1. Stator Red -> Battery (with an inline fuse rated below the ampacity of the wire)
  2. Stator Yellow 1 -> Rectifier Yellow
  3. Stator Yellow 2 -> Rectifier Pink
  4. Rectifier Green -> Good grounding bolt on the engine with a ring terminal. Don’t try to tie it into a harness ground. Better to run a jumper if you need to.

Polarity on those stator yellows doesn’t matter, so they can be connected either way. If you go for it, let me know your results or if you need any help!