PC800 Fuel Injection – Page 8 – Not Your Average Engineer

January 19, 2012

Working on Injector Bosses

Lately I’ve been working on the fuel injector bosses for my fuel injection conversion project. The other night I started machining the bosses themselves. The above video is a sped-up version of me machining the bosses in my living room. I believe that machining in my living room levels me up in the world of engineers.

I was thinking about having the hose fittings come out the sides of the bosses but this would impede being able to bolt the injectors to the throttle body.

I can’t put them straight out the top either without impinging upon the water pipes coming out of the cylinder heads.

This side is a more likely candidate. However, I will need to get a 90 degree elbow to make sure I don’t bend the high pressure fuel hose. I will be picking that up this evening.

I will be shaving down about 1/4″ from the top of the blocks to make sure they fit properly once I have set the retaining bolts to hold the bosses and injectors to the throttle bodies.

I might be in trouble with the alignment of the injector wiring. Hopefully I can make it fit properly.

January 8, 2012

Injector Bungs Installed

Today I successfully installed the injector bungs into the PC800 carbs. Many months back, I had drilled the requisite holes for injector bungs just below the butterfly valves. Recent playing with the electrical system on my XL500S sparked renewed desire to complete the PC800 fuel injection project. After cleaning up the holes a bunch yesterday, today I was ready to JB Weld the bungs in place. The above picture shows both bungs JB Welded in place and waiting to be trimmed down to the cylinder walls. The orange things are injectors.

I used JB Weld SteelStik for its superior ability not to drip everywhere. It begins to set in about four minutes so working time is rather limited. The packaging claims that after an hour the stuff is structurally ready to be used. Not bad for a product that comes in a tube.

After a lot of quality time with a dremel tool, I shaved down the injector bung to be flush with the throttle body wall. I intentionally placed the injector partially into the throttle body passage.

Checking for clearance on the extra PC800 engine that Bart has been loaning me for many months. Thanks Bart!!!

Plenty of clearance for some injector bosses. The bosses are next on my list to make. More on that later.

The injector on the other side. In spite of how it looks, there will be enough room for the plug to clear the cylinder head. Hopefully I won’t run into trouble with things melting from being so close to the hot head.

Looking down the throat of one of the throttle bodies. Nice and smooth all the way down. The injector is just peaking into the bore.

Good fit in this direction, too. The black thing above is the air cleaner box. Plenty of room to route fuel lines and whatnot.

My temporary workbench. I have another project laid out on my wooden workbench so thus I am using this old table I got from an ex girlfriend many years ago. The next step is to use the brass blocks (one is just above the permanent marker just left of center in the photo) to create injector bosses. I have everything I need except for a ream of appropriate size. None of the shops around here carry reams. It looks like I might have to suck up the cost and buy one from McMaster Carr unless I can find a better local source.

Following the injector boss creation and mounting, I will then complete mounting the sensors on the air intake manifold (temp sensor, manifold air pressure sensor, ambient air pressure sensor). I also will mount the throttle position sensor onto the throttle bodies with an aluminum plate that is out of the frame of the photo. Then it will be time to install the wide-band O2 sensor and associated gauge on my PC800, purchase a fuel pump, pressure regulator, and fuel filter, and start installing things. Perhaps by the end of winter term (which starts tomorrow), I will be assembling parts onto the PC800 and be in the home stretch of this project!

November 1, 2011

PC800 Fuel Tank Modification

Over the weekend, I finally had some time to work on the PC800 fuel injection project again. After months of planning to weld on the fuel tank and insert an internal tank pump from a CBR600RR, I finally decided against it due to several factors. First, the shape of the tank is difficult to weld upon. Second, I would have had to recess the tank which would effectively reduce the total volume of fuel that I can access. Third, the internal pump would have taken up more room and thus reduced how much range I could get out of the tank. Therefore, I decided to do an external pump. At the moment, I am eyeing a Walbro GSL393 155 lph pump that can run at the pressure (~45 to 50psi) I am after. They run roughly $100-150 depending upon which website I purchase from. I will also have to purchase a fuel pressure regulator (more on that later). My main concerns are that the pump will use too many watts and overload the PC800’s electrical system, and that the pump will need a low pressure feeder pump depending upon where I can locate the unit.

After making the decision to go with an external pump, I went about modifying my spare PC800 fuel tank and fuel level sensor to accept a fuel return hose. The brass fitting with the blue cap above is the result. I had to cut some metal around the O-ring flange on the tank and drilled a hole through the fuel level sensor housing as well. After a few runs to the hardware store, this is the resulting solution. I have yet to test it for leaks beyond letting some gasoline sit in the tray of the fuel level sensor. A full gasoline test will be coming up when I have the time to take a couple of gas cans to the station and have them filled. I don’t anticipate any leaks but one never can be too cautious.

This modification will not affect the fuel level sensor’s operation.

Now that I have decided to go this route, I will need to purchase a fuel pressure regulator. Looking around online, it appears that I will be paying somewhere between $50 (used on ebay) and $150 for a decent unit. If I choose the right one, I will also have the ability to have an external fuel pressure gauge. Naturally, I want more gauges on my dash. I expect that to run another $50 or so. Hopefully in the next month, I will be able to find the money to purchase these components. However, first I need to finish modifying the carburetors into throttle bodies with injection ports. That is going somewhat slowly as I still haven’t figured out how to shape the injector ports properly. I have some ideas on that but haven’t come to a full resolution yet.