I haven't stopped by here in awhile...

I just finished my school project (and school) and now have time to begin that daunting task of building an EFI system for the savage.  I am about to begin bashing away at a chip in a couple weeks to get my basic code down.

Sensors required:
Intake air temp
Manifold absolute pressure
Throttle position
Cylinder head temperature

Hardware required:
Injector
Intake manifold
Throttle body
Fuel pump
Fuel pressure regulator
Fuel return line

If anyone sees anything I am missing please make a note of it for me.  I will be using the stock components to account for where in the rotation the engine is and it will therefore be "wasting" gas by injecting when the intake valve is closed at BDC since the stock ignition fires twice (not knowing when TDC occurs...only when TDC and BDC occur).

I already know where to get most of my information for basic numbers on fuel per air density for a given size of engine.  There will be no feedback loop to keep the a/f ratio at any specific level initially.  I will probably do some type of visual interface (LCD) to give feedback.

If I ever complete this project:
1.  Is anyone else interested in converting their bikes as well?
2.  How much of the work are you willing to do?  I can program a chip with my code easy enough after I bash through it and I'd only charge the actual cost of the chip...but I'm not about to solder every circuit board together for everybody free of charge!
3.  Would anybody be willing to pay for complete units where I include a charge of around $20 per hour of labor I put in added to the cost of the unit?
4.  Would anybody just want the circuit diagrams and chip alone and then they would build everything else themselves if they wanted to convert to EFI?
5.  No, I would not be willing to stock every single component involved to make it a "complete" kit...only the electronics involved.
6.  Yes, I could do custom features if anybody has good ideas (altering fuel tables by X% every 500rpm for example).
7.  No, I would not consider doing an ECU that controls ignition at the same time.

Oh hell no!  One of my favorite things about the Savage is it's simplicity.  I'll stick with stone knives and bear skins as long as possible.

While the project is most interesting, I am in the same school as Savage_Rob.  

Savage_Rob wrote on 12/31/69 at 16:00:06:


I'll give that an Amen brother - the last thing I want is yet another computer to break and leave me on the side of the road!

The idea is cool but really not needed on this bike. like everyone else is saying, this is just a simple single cylinder bike. What would it really gain having EFI? If you are going to do it as an "experiment", goto a cycle salvage yard and find a  newer crotch rocket that got wiped out. I have seen some with EFI on them or maybe another touring bike of some brand or another. at least You'll be ahead with parts for your project!!

Interesting project. I read an article on the Suzuki M50 in Motorcycle Consumer News & they liked what the 32 bit engine management system did for the engine. It's a similar system to the new Gixxer 1000. I wonder if a future S40/Savage might have one. If they had a reliable system that would optimize the ignition curve & fuel injection for maximum power at all RPMs factoring in engine load, air density, throttle position & intake vacuum it would be cool to see how it ran. One nice thing is that it would automatically compensate jetting for muffler swaps. I'm happy with the carb but I'm always wondering about those unknown possibilities.   8)

45mm throttle bodies would be a good place to start.

Clive W  

This is hypothetical as the Savage's ports won't go that big but if you were looking for maximum output you would use a 46.7mm i.d. carb and inlet port. For the exhaust port and first 8-9" of the header you need an i.d. of 39.7mm tapering out to 46.7mm over a distance of 1.5". Continue the 46.7mm i.d. untill you are 39" from the port then step up to 53mm for 4.5" then into the open air. By which time you would want to change the cam and so the pipe,it neverends.
Of course this can't be done and if it could it would run like a bag of nuts most of the time.

A Raask pipe and amal 38mm carb would be the safe option. Any 38mm i.d. header in fact.

Clive W