MicroSquirt – Page 4 – Not Your Average Engineer

I installed the coolant temperature sensor in line with one of the coolant lines coming off the engine heads. It will restrict coolant flow a little but hopefully not enough to hurt the PC800 engine. I had to improvise with some coolant hose that I had laying around the shop to fit. I will need to check for leaks once I have the fuel injection system up and running, and the engine hot and coolant system operating at pressure.

Wiring is coming along well. I am done with wiring in the coolant temperature sensor, the throttle position sensor, the manifold air pressure sensor in the throttle body, the air pressure sensor that will live somewhere else on the bike to monitor atmospheric pressure, the intake air temperature sensor, and the fuel injectors. I also connected the relay for the high pressure fuel pump. Next up is to connect the spark pulse sensor wiring and the spark generator wiring. I’ve decided that I’m going “all in” and will have the MicroSquirt control the spark system, too.

I still need to wire in the indicator LEDs and the tilt sensor. Also I need to think about how the run/stop (kill) switch on the handlebars will get wired into the setup. Maybe I will use it to cut the relay power to the fuel pump.

It looks like next weekend I should be able to start tuning the bike. Exciting times ahead!

After yet another test ride where I had fuel pouring out of the overflow on the carbs, I decided that I was done trying to diagnose an intermittent problem in the stock fuel system on my PC800. Yes, it has finally become time to install the fuel injection system that I have been working on for several years.

The first course of action was to install the high pressure fuel pump I bought off ebay from a 2010 Honda Fury. After some modification to the PC800 plastics and relocating the wiring harness plugs, I was able to fit in the high pressure fuel pump.

Purists will not like how I had to cut part of the plastics out to make the pump just slightly visible from the outside. Then again, purists aren’t interested in fuel injecting a PC800.

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With the trunk lid closed, a little bit of the fuel pump is visible. I can live with that.

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I drilled through a spare PC800 fuel cap to make a return line for the high pressure fuel pump.

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Some high temp RTV helps hold everything together. It isn’t a perfect or a pretty setup but I didn’t want to have to drop out the existing gas tank and put in the gas tank I modified several years ago. Maybe down the road I will do that but for now this works well.

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High and low pressure lines routed up from the fuel pump. I should note that I do not have a low pressure boost pump installed at the moment although I think that I will end up having to put one in in order to access the lower half of the fuel tank. Testing will be needed before I can make that determination.

The Honda Fury throttle body and fuel injection intake manifold near the position where it will be once everything is installed. I am going to hang a UNIPOD or similar filter off the front of this. I still need to figure out where I can pull vacuum from on this setup for the secondary MAP sensor I am running to do on-the-fly altitude correction.

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Top-down view. I am going to be using some wide diameter fuel hose with 90 degree bends pre-made to connect the injector intake body with the PC800 engine intakes. It isn’t the best way to do it but I don’t want to pay for a 3D printed metal intake adapter. Maybe down the road I will do that.

Here is a picture of the “brains” of the MicroSquirt that will be running the entire show.

More to come soon!

Tag: MicroSquirt

Coolant Temperature Sensor Installed and Most Wiring Done for PC800 Fuel Injection Conversion

Installation of a High Pressure Fuel Pump on the PC800