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Electronic Fuel Injected CB77

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MBellRacing
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Electronic Fuel Injected CB77

Post by MBellRacing » Thu Dec 22, 2011 9:03 pm

So I'm not really sure where in the forum this should go. I'm mostly heading down a "cafe racer" style bike without doing the over-popular clubman bars and fiberglass seat. I have been thinking out loud to my neighbor Bob Guynes (built that famous dual engine Bonneville racer) for a while about fuel injection. He's always argued with me on the high points of a good system, until just the other day he said, "Well, when you think about it, why not?" He was right. Why not? Why bastardize these pristine old bikes with electronic ignition and non-original parts all while shaming anyone that thinks about doing away with the troublesome, ancient carburetors?

So I started my research. Found a small company run by a guy named Matt (I like him already...) called Ecotrons. They've made just a couple products, but they have a very clever set of brains behind how motors should be tuned, and how they can tune themselves. Matt custom assembled a kit for me and I'm in the process of installing it all now. Nothing is bolt-on, it's all "make it fit or do without it". The kit is comprised of everything I need to get this motor running on fuel injection, minus silly things like a Variable Reluctance sensor and a trigger wheel. It comes with two 26mm Mikuni-style throttle bodies, a small fuel pump, a fuel pressure regulator, two 128g/min injectors, manifold pressure, throttle position, intake air temperature, and engine temperature sensors, two modern ignition coils, and finally a giant wiring loom ready to plug into the ECU.

My plan is (and always has been) to make it very hard to tell that the bike is fuel injected. Before the photos, let me explain where things are going. The ECU, ignition coils, sensor clips, and most of the wiring will be under the tank where the stock GIANT ignition coils had been before. The fuel pump will be housed in the stock tool tray behind the side covers and feed the injectors via a long black line that hugs the backbone of the frame and the fuel pressure regulator hidden under the back half of the gas tank. The pressure regulator will send excess fuel back to the tank via a fake overflow line in the gas cap from the space between the tank and the steering head. The trigger wheel is mounted on a little standoff to the generator rotor and the VR sensor will have a custom bracket holding it under the stator cover. The cover itself will need a big spacer so it clears the VR sensor (those things are relatively HUGE). The engine temp sensor is conveniently placed on one of the bolts under the stock ignition rotor cap and the wire is the perfect size to fill up the rubber gasket/grommet. I'll be rewiring the whole bike with a custom loom as to cut down on doubled-up wires. I'll be installing a NOS CYB93 stator and a Charley's Place regulator rectifier. Along with the LED headlight and taillight (seen here: http://www.honda305.com/forums/led-head ... t8546.html) I should have plenty of juice to run all the ignition/injector drivers and the fuel pump.

Now with the photos:

Test fitting the throttles...

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Tried tightening them down to measure air filter length and broke off a cheap little vacuum nipple...

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...So I relocated it on one with a stronger brass fitting and filled the old holes on both throttles...

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Trigger wheel randomly placed on rotor to check out VR spacing...

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Engine temp sensor in the points cover. Don't mind the old epoxy or the fact that the cable is heavily bent. I checked to make sure it wasn't kinking, it just looks bad under the insulation...

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Wouldn't know it was there! Also, don't mind the stuck screw driver bit-- didn't notice till I saw the photo!...

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MAP sensor hidden between the engine and frame...

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Coils and ECU in their new home. Need to wrap the spark plug wires in some electrical insulation to make sure they don't talk with the ECU's internals...

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Fuel pump in the tool tray...

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...Once again, you'd really have to be looking to find it. The blue lines will end a bit short of where they are and be on quick disconnect fittings to black lines out to their sources...

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Hard to see with the stuck quick disconnect from the old cross tube, but the fuel pressure regulator is tucked up under the side of the tank...

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I seem to have measured a bit shallow for my filter length. They fit, but are VERY snug...

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And finally (for now), the CYB93 stator to replace my current one...

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Now that I have a place to share, I'll post updates regularly. I'm trying to get as much done as possible before the 24H of Daytona, but testing and seat fittings are keeping me from the project. Worse comes to worst I'll just end up finishing it off late in January/early February. I need to done before March though-- more on that later.........

Hoosier Tom
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Post by Hoosier Tom » Thu Dec 22, 2011 11:57 pm

Tip-o-the-hat to you, sir. I will be eagerly watching your progress. Very neat project.

HT

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Michael Stoic
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Post by Michael Stoic » Fri Dec 23, 2011 2:34 am

What a great feat of engineering and custom fabrication! I love the idea and look forward to following your progress!

Michael Stoic

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brewsky
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Post by brewsky » Fri Dec 23, 2011 6:42 am

Very interesting!!

Are you going to use single or dual O2 sensors?

A friend of mine installed a Terminal Velocity self learning system on his Yamaha 1300 twin after intake and exhaust mods and it was impressive. It had no adjustability though and an unknown (or secret?) A/F target.

The system you have appears to be much more versatile.

Looking forward to seeing the results.
66 dream, 78 cb750k, 02fz1, 09 wing

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Snakeoil
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Post by Snakeoil » Fri Dec 23, 2011 10:51 am

Very interesting. Looking forward to the end results.

Any concerns the vibration will saw thru your tool box fuel lines?

Is it your intent to dyno tune the engine once you have it finished?

regards,
Rob

MBellRacing
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Post by MBellRacing » Fri Dec 23, 2011 11:36 am

I will be using one wide band O2, switched between the two pipes for initial tuning. I'll then install the narrow band O2 for constant use for the self tuning of near-stoichiometric running on the highway-- probably. I can also just get it close and run it open loop and figure it all out myself. I'm not sure yet. Their ECU is incredibly small, which is awesome. It lets me put it really wherever I want. The only downside to this is that it doesn't have an internal wide band driver and needs a large box to go with it. Unless I want to mount that somewhere as well, I'll not be able to monitor wide band O2 stats all the time. Their software (and ECU) has a lot of auto-tuning capability. It's sort of their claim to fame. They have some creative means of calculating the volumetric efficiency, and therefore how much fuel the engine probably needs. The gaps between the formula and reality are the only numbers you input.

The vibration on all the parts will be an issue. The ECU doesn't need as much vibration dampening, so it's just sitting on the powder coated frame in two spots. If I get worried about it, I may just put some rubber under it to further buffer the sharper stuff. The fuel pump was the one I was especially worried about. It has about 1/8" of hard-ish rubber insulation around it. The fuel lines are all soft so they should be okay. I could be wrong, have people had experiences with this? As far as the sawing effect goes, I opened up the smaller holes quite a bit more than they had to be. I figure it'll only "saw" if it can grab it on two sides so the vibration becomes a striking or sliding motion. I'm trying to make sure this doesn't happen. The big injector line is pretty tight, but it's also a massive line. I'll check it after the first or second time out to make sure it it's being cut.

Thanks for the support so far. I'm going to TRY and get over there today to do more work. It's all pretty fast stuff, but it's still time I need to drive to the shop and get to work. There are some things I have little or no experience with that I need to sort out. The throttle cables, for instance. Is there a kit I can buy that will enable me to make them as long as I want, go to the single ended bit (as in stock CB77) by the grip, but then split into the more modern style end by the throttle? I guess I need to make a 100% custom cable, just not sure how to go about it.

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brewsky
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Post by brewsky » Fri Dec 23, 2011 3:14 pm

Some cycle shops keep cable kits for custom fitting, so you might find one close that can modify a stock throttle cable ........or even make one from scratch.

Motion Pro will also fabricate custom cables.

Any way to link the throttle bodies together and use one cable?
66 dream, 78 cb750k, 02fz1, 09 wing

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