Fuel injection

Douglas Binder /

It started!!!

Let's back up. As some of you know, I've been building a land speed racing Puch Maxi. After the last event in September, I decided to start making big changes to the bike. In particular, I wanted to cast my own cylinders and also add fuel injection. See my other thread about the cylinders but this is about the EFI. I wanted EFI for a few reasons: control over the fuel mixture, control over the ignition, and the ability to run a large throttle body without having mixture issues like you would with an overly large carburetor. It is powered by a total loss battery. Remember that I only need to go wide open for 1.5 miles then get back to the pits.

I started by buying a kit from China. It included a throttle body, fuel pump with regulator, and injector. I was frustrated by the lack of good documentation but, fortunately, I discovered Speeduino, an open source EFI project based on an Arduino Mega2560. I bought an NO2C board and have been working on it the last few weeks. For crank angle, I machined a 24 tooth wheel and use an optical interrupter to detect the holes. I also decided that I wanted two injectors because I didn't feel that one injector could handle the range of rpms that I hope for.

For monitoring and tuning, I used a Raspberry Pi with a 7" monitor running Tuner Studio. This will be mounted in front of the handlebars eventually but now it sits on a stool by the dyno.

Re: Fuel injection

Douglas Binder /
IMG_20190407_112046504.jpg

The crank sensor.

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Douglas Binder /
IMG_20190407_135030182.jpg

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Douglas Binder /
IMG_20190407_145101412.jpg

Throttle body

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Douglas Binder /
IMG_20190407_145104996.jpg

Bit of a mess but I'll clean it up later.

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YES!

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excellent...

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Ľ̷̝̽͒i̶̛̼͑͠ȁ̸̧̛̽m̵̻̟̯̀̅ ̷͎̙̽̊F̶̲̺͑̓ F /

Whoah.

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> Douglas Binder Wrote:

> -------------------------------------------------------

> It started!!!

wait wait wait, you mean it actually fires? wow, i figured this would be like 3-4 months of screwing around. this is awesome.

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Douglas Binder /

Graham, ye of little faith! It fires and runs smoother than I ever heard it. Still need to connect the wideband and some sort of engine temperature sensor. I plan to switch back to the cylinder project because I am experimenting with plating...

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" Any sufficiently advanced technology is indistinguishable from magic. - Arthur C. Clarke"

made me think of this one!

i still haven't got my plaster to stay in one piece for a burn-out... that said i haven't been working on it much lately... spring on the farm, tractors to fix and trees to cut down and all that jazz.

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Looks great. Breaking into new moped territory. Keep it up

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Just like the casting a cylinder thread, most of this thread is going straight over my head. Iam excited to see what type of sorcery goes into this and how it performs. Awesome work.

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Josiah Radebaugh /

I'd like to see it run/ how it performs as is.

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Awesome!

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Are you still using the throttle body and whatnot from the Chinese kit? Is it one of the sets that comes with a Megasquirt clone ECU?

I keep rambling about doing an efi 2t but haven't figured out how to handle fuel/air feedback. In my head I'm thinking EGT would work for that, but don't know enough about the programming to know where to start.

I like the idea of a setup for the street that is programmed to save the cylinder. Like if temperatures climb over a preset number it goes richer and richer until it floods.

I also have this fantasy of a rig set up with two tanks, two injectors, fuel curves, timing curves, etc... So I can flip a switch and go between pump gas and whatever dumb blend I want to play with.

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Douglas Binder /

This is the kit I bought: https://www.aliexpress.com/item/microsquirt-II-based-EFI-motorcycle-Motorbike-Motocross-ATV-scooter-small-engine-Electronic-Fuel-Injection-kit/32786077851.html?spm=a2g0n.description.0.0.5b1bb3c5KNPpBp

I am using TPS/RPM (Alpha-n) for fuel ratios. Open loop. I only operate a WOT so don't need to be too fancy. What I'm doing probably won't be too useful to a normal moped. I think that adding EFI wouldn't be worth it for most people. I'm doing it for a few reasons: I want to try it, I want that last few percent of power, I have the background in embedded control systems and I have a lot of equipment available to me.

Re: Fuel injection

Matt Mahloch -- MBM Customs /

OP

I enjoy reading what you’re working on. It’s very cool watching with skills tinker on these little machines. Good luck getting that thing working properly. You have any events set up yet this year?

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Douglas Binder /

There's an event in July.

Re: Fuel injection

> Douglas Binder Wrote:

> . What I'm doing probably

> won't be too useful to a normal moped. I think that adding EFI wouldn't

> be worth it for most people. I'm doing it for a few reasons: I want to

> try it, I want that last few percent of power, I have the background in

> embedded control systems and I have a lot of equipment available to me.

I want to do it just because. I did come to the conclusion that I need a few more folks with your level of understanding to do it first since I don't understand all the variables enough to make a good plan. I need a bit more to build on.

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Douglas Binder /

Thomas, the reason I post the stuff I do is in case anyone wants to try it. The casting stuff is pretty straightforward but requires a lot of equipment. The EFI doesn't need too much except you need to come up with a trigger wheel. The issue is that there is a steep learning curve. You can buy some of the parts like the control board, etc, but then you need to get a throttle body somehow mated with your engine. I imagine that I will eventually cast the throttle body to reed housing adapter in aluminum but, for now, will use the 3D printed part. The throttle body that came with the kit has a built in intake air sensor, manifold pressure sensor, and throttle position sensor. Because there was no documentation, I only use the TPS and that was fun trying to figure out which wires to use. The thing is sealed up so I had to do some detective work. I have a lab grade power supply that I used to put 5 volts into the thing and watched the remaining wires while I moved the throttle.

I could go on but I should get back to work.

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Not to go of course but that pull start looks like it was made from a stock magneto cover a spacer and a chines pull start. How did you make a the magneto paw?

Could you make a pull start thread. The pullstart looks good!!

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Douglas Binder /

Rocco, you are correct. I cut out the center of my flywheel cover, 3d printed a spacer, then bolted on a Chinese pit bike pull start. The paws engage the two allen head bolts on the flywheel that you can see in one of the photos.

Re: Fuel injection

> Douglas Binder Wrote:

> -------------------------------------------------------

> Rocco, you are correct. I cut out the center of my flywheel cover, 3d

> printed a spacer, then bolted on a Chinese pit bike pull start. The

> paws engage the two allen head bolts on the flywheel that you can see in

> one of the photos.

You use Allen bolts!? This is fucking ingenious. Thank you so much!

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