Whatever you want to call it, it is a mod that "Eliminates Retarded Timing"
The ignition timing on the Hayabusa in the first few gears, under 8krpm, is retarded to varying degrees. It has been suggested (and the most probable reason) that it is retarded to stop you flipping the bike. Adding the Mod will not make the bike uncontrollable.
It makes it crisper under 8krpm and is solely a drivability mod. I am aware of no power
improvements or decreases through its usage.
What you effectively do with this mod, is to take the output from the Gear Position Sensor (GPS) and intercept it before it gets to the ECM. we then tell the ECM that it is in
a chosen gear all the time, thus removing any ignition retardation that may be mapped into the bikes computer.
The output from the GPS is the Pink wire, ...we isolate this at the GPS connector.
We then add a resistor, of the specified gear value, onto the ECM end of the pink wire, and jumper this to
ground, or the black wire.
It is a simple mod.
Now the decision bit...what gear do you want to fool the bike into thinking
it is in?? Well, I have tried 4th, 5th and 6th gear. 4th is okay, 6th is good,
but 5th is the best (In my humble opinion) and this is what I run and fit to
bikes I work on.
Now, for 5th gear the resistor value is 6.8K ohms, for 6th gear it is 15K ohms.
I recommend the 6.8K ohms, 1/4 watt resistor, but it
is up to you.
TOOLS REQUIRED IN ADDITION TO THE BIKE TOOLKIT
Thin bladed screwdriver, or thin, sharp pointy thing.
Resistor of the correct resistance, 1/4 Watt will suffice
Soldering iron and solder if you want to make sure of your connections
GETTING TO THE AREA
Remove front seat
Lift and support tank
IDENTIFYING CORRECT CONNECTOR BLOCK
Kneel on LH Side of bike. Underneath the Fuel petcock, and closer to you, you will see the main wiring loom. It is black, wrapped in tape and flattened as it goes over the chassis.
Follow it forward from this point about 3" you will see a white connector. It looks like 3 tubes stuck together on either end.
This is the Gear Position Sensor connector.
FOR REFERENCE TO ENSURE YOU HAVE THE RIGHT ONE
If you look up next to the back LH Side corner of the air box, there should be another of these connectors, the Throttle Position Sensor (TPS) identical but in black.
Right, back to the white one.
About 1" further forward from the GPS connector is a black reusable zip tie. Depress the nodule and remove. this allows you to pull the
connector block up high enough to get either your fingers onto the clip to depress and pull the 2 halves apart, or, like I have to (chubby fingers ) get some long nose
pliers on it and pull apart.
Once inside the connector, the RH Side one is the ECM side. this is the one we work on.
REMOVING THE PINK WIRE SPADE CONNECTOR
Look inside the RH Side block, see how the spades are held in, with a little one way clip??
Identify which one is the pink wire, depress the clip and pull the wire with spade connector intact out the back.
Take the resistor and the pink wire. Either push one leg into the circle piece at the side of the spade
and solder or attach how you like....then tape up as this does not go back into the block.
then, with the other end, this needs to be attached to the black wire, (but remember this needs to be reinserted into the block if you remove
it) either remove black wire, strip a little coating back (melt with soldering iron is the best way) then solder
on, ensure that the connection is good.
Tape up so they cant move or rattle loose,
Re connect the connector block
Checking you got it all back right, leave tank up, just in case..
Start bike, out of gear.
Set fast idle at about 2krpm.
Pull in clutch revs should drop, then let clutch out, revs should rise.
If they don't, it isn't connected right. (its neutral timing, vs other gear timing....there is a difference at low revs)
If this doesn't happen, you haven't got a good enough connection somewhere...go back, check your work.
If it works, turn bike off, replace zip tie, check to make sure it all looks safe and isn't going to fall off,
While you are in here, check the fuel hoses for signs of kinking, especially if you have had the recall done, as this is when the main feed from the
petcock has to be removed. They don't put the counter twist in. So that when you lower the tank the fuel line gets a twisting
force. When it gets hot it kinks. If it does have a wrinkly crease mark in the hose (normally about 1" from the
petcock spigot), you need to cut the offending piece off and reinstall, but with a clockwise twist in it...but you
don't want to get petrol everywhere!!! see next project!! LOL
Lower tank, replace seat, wipe off dirty paw prints.
Be careful on first ride, as you have now taken out the Suzuki installed safety feature to stop you flipping the bike...it will be SO MUCH MORE RESPONSIVE from junctions, small throttle openings etc...it is like a different bike.