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Old 10-14-2009, 11:43 AM   #1
toplessFC3Sman OP
Joined: Oct 2009
Oddometer: 68
Project '73 CL350... fuel injection and electronic spark control?

Well, some friends and I picked up what the seller advertised as a '71 CL350, but after a bit of research appears to be a '73 (k5).

Anyhow, this is my first bike, and I'm working on getting back into good shape over the winter, which will involve the usual battery of de-rusting, painting, polishing, new rubber, cables and whatnot.

However, I'm very tired of dealing with the carbs over the past summer (as well as tank gunk), and the broken choke plate on the left cylinder. Instead of getting a new set of carbs and continue to mess with the adjustments... fuel injection may be an interesting project with potential gains in drivability, cold-start behavior and fuel economy... plus I don't think its been done before.

The plan is to go with a MegaSquirt open-source engine controller since not only are they cheap ($200!), but I've used them on project cars and through FSAE before, so i'm familiar with the hardware and software sides.

Then, i'd get some throttle bodies with injectors and fuel rails from a fuel injected bike (i'm thinking a CBR600 F4i since they come in banks of two, can be found very cheaply including injectors and everything), and have an integrated throttle position sensor. I'd need an in-line fuel pump, filter, and to add a return to the tank (probably just as a T in the tube that connects the two sides), but all of this is pretty minor.

On the signaling side, the contacts can be replaced with a toothed wheel and VR sensor or hall-effect sensor pretty easily to track engine position and speed (I have a spare sensor/wheel from my project car), and then use the megasquirt to control spark to the individual cylinders (it does have an odd-fire mode which should work)

The last hurdle would be tuning, but with a narrow-band O2 sensor and just tuning to stoich (or close anyway, to keep temps down), it shouldnt be hard, just a longer process since I dont really want to be riding with the laptop open on the gas tank... disaster much?

In addition, this would allow me to add a tach that actually seems to respond to the engine (the old one seems like its trying to move through peanutbutter...), as well as an idle valve, no need to ever re-jet, and if i wanted to go all-out, launch control, shift lights and some other neat little functions.

$200 for MS, $50 for throttle bodies/injectors etc, $70 for fuel pump, $30 for O2 sensor, $50 for misc. wiring supplies and electronics...tempting...

toplessFC3Sman screwed with this post 10-23-2009 at 08:25 AM
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