Motorcycle EFI project

[Jake Sternberg]

Welcome to the list!!  Sorry about the discouraging remarks people posted,
despite the fact you stated any _help_ would be appreciated.  Come on,
people, if you dont know how to do something, dont say it can't be done!

anyway.. I myself am working on a project almost exactly like yours, mine
being a 1980 suzuki GS1100 four with sixteen valves, basically the same
thing as your XS1100 (also air cooled).  I'm so sick of my carburetors
that i've contemplated catapaulting them into mexico, but my bike is my
main transportation so i've decided to wait until i install fuel
injection.

In the mail right now (should arrive tomorrow) is a complete EFI setup
from a '84 volvo 240 with bosch LH-jetronic.  The system uses a hot-wire
MAF sensor for its primary metering decisions.  It uses approximately
17lb/hour fuel injectors which allow the 2.1L volvo engine to produce up
to 120 horsepower in production form.  they're just right for our needs.
The fuel rail has a manifold vacuum referenced pressure regulator at the
end, and i intend to cut it where i need to, and bridge the pieces back
together in the appropriate spacing for my motorcycle using 1/2" ID fuel
hose and hose clamps.  I intend to make an intake manifold out of gutted
carburetors while I fabricate a more elegant piece out of aluminum.  I
happen to have access to a nice machine shop with TIG (electrical arc)
welders which can weld aluminum, and i'll be making some parts with
lathes..  but the same effect could of course be achieved with cut metal
tubing and short pieces of radiator hose and hose clamps if you lack those
resources.  speaking of resources, one of the main reasons i'm going with
the LH-jet setup i speak of is because a buddy of mine happened to have it
lying around and i'd rather experiment with "what's lying around" than go
out and explicitly purchase a setup without knowing if it'll work well.

I fully expect this FI setup to operate my motorcycle satisfactorily from
the get-go, despite the fact that its breathing characteristics are very
different from a tractor-engine-like 8-valve 2.1L volvo engine (which
rule, dont get me wrong).  One of my ultimate goals for this system
include equal or superior drivability and performance to a perfectly tuned
carb setup.  Since i've never cracked open an LH-jet ECU, i've already
come up with a few ways to tweak the system without modifying a thing,
in case I can't find solutions within its built-in flexibility.

for enrichment on throttle-whacking, i intend to explore various places
for the connection to the fuelpressureregulator's vacuum reference.  By
letting it see an increase in pressure faster than it normally would,
pressure in the fuel rail would jump during throttle openings and provide
an accelerator-pump effect superimposed on the computers' intentions.
I have other ideas like this, but ideas are all they are until i try them.

for oxygen sensors, i'll be mounting one at each exhaust port, with
bi-color LEDs on my instrument cluster to indicate rich/lean status for
each.  the ECU will get its info from whichever of the four i tell it to.

Of course, when i get the gear on my bench I intend to open it all up and
catalog all the chips in everything, and read the prom(s) (assuming there
are any!) to see what i can figure out.  Volvo EFI setups like this are
cheap enough to acquire to make fully reverse-engineering them worthwhile.
According to my friend sending it, there are two "boxes" in the system,
one is the ECU proper and the other is under the hood with a good number
of wires and a vacuum transducer mounted right on it; i suspect this box
has a lot to do with the ignition and timing since LH-jetronic does not
normally involve itself with that task.  That's great, because the
ignition system on my bike is fine for the moment and it will be that much
easier to tweak the new EFI setup without having to worry about spark.

So, rest assured, myself and others on this list are embroiled in the same
exact endeavor as yourself, many of us on 1100 fours, of course :)
I am quite determined to be running on EFI as soon as possible, and i'll
share all of my findings and formulae with the list, and you are more than
welcome to simply trace my steps on your own bike if you want to just do
it first and then learn.  The only factory bike EFI out there people talk
about is the kawasaki 1100 which, as i understand, were so strange and
crappy that many of them were replaced with carbs!!!  A new option is
definitely needed.

-Jake

> From: Jemison Richard <JemisonR at tce.com>
> Date: Wed, 30 Sep 1998 09:33:44 -0500
> Subject: New List Participant - very new 
> 
> 2)  The real reason I'm here is that I'm a motorcycle enthusiast and want to
> design (or adapt if someone much smarter than me has already done this!
> This will NOT hurt my feelings any) an electronic fuel injection system that
> would be generic enough in nature to fit many similar engine sized Japanese
> bikes that were carbureted.
> 
>      At this point I don't even know where to begin.  Of course, from my
> perspective, existing units are attractive but reprogramming the control
> computers is a black box for me.  One thing I've toyed with is single board
> computers (SBCs).  I worked a bit with process control in the pharmaceutical
> industry about 8 years ago and got some experience programming these guys.
> They're cheap and readily available and of late have a lot of inexpensive
> digital and analog sensing options.  Big question is, has anyone gone down
> this path and if so, is it worth looking at?  
> 
>      I again apologize for what are probably pretty simple (and possibly
> silly) questions.  I'm just looking for some good initial direction to
> pursue.  Any help will be gratefully received!
> 
> Rick
> Indy
>