Motor experts - a simple question for you

[IG.]

I am just trying to understand something. We all know that when the clutch is pulled with PC on the bike, the RPM goes a bit down, and when the clutch is releases the RPM goes a bit up.

Same could be said about the dealer mode. Since I installed the switch, it's easy to switch to the dealer mode. So, if the bike idles and I switch to the dealer mode, RPM goes up. And actually, if anyone dares to ride while in dealer mode, the bike acts a lot more aggressively at least in lower gears.

What I don't understand is how it's done. The throttle is in the same position, so the throttle bodies have the same opening. Obvious answer would be that the PC reduces amount of fuel injected for the RPM to drop. However, wouldn't that cause the lean issue?

And in order to increase RPM, would more fuel really do it? Wouldn't the mix become too rich?

So, all in all, just how the heck PC or ECU can control RPM for the same throttle opening?

 

[MikeSomething]

Uhm, I might be outta the loop here... You have a Gen1 and a switch that connects to the big clear, white harness inside your tail section, and it puts you in "Dealer Mode", the mode to check codes. And you're saying you're bike feels more powerful while in dealer mode?

 

[Commuta_Busa]

it's the combination of fuel and timing that will effects the rpm at the same throttle angle.

 

[IG.]

Uhm, I might be outta the loop here... You have a Gen1 and a switch that connects to the big clear, white harness inside your tail section, and it puts you in "Dealer Mode", the mode to check codes. And you're saying you're bike feels more powerful while in dealer mode?

That is correct! Try it. Like I said - it's very noticealbe in lower gears.

 

[IG.]

it's the combination of fuel and timing that will effects the rpm at the same throttle angle.

So, retarding timing (i.e. shooting fuel a little too late and with adjusted amount) does the trick, right?

 

[megawatt]

So, retarding timing (i.e. shooting fuel a little too late and with adjusted amount) does the trick, right?

Uhhhh no. Retarded timing does not delay the fuel "shooting" like u said. It delays the timing of the ignition spark by a few degrees.

 

[Commuta_Busa]

changes to the FI only change the duration of the "squirt" while changes to the ign timing would either spark sooner or later in the cycle.

 

[omslaw]

Perhaps it's changing the fuel map...similar to what a TRE does? ???

With a TRE installed, RPM will rise when the clutch lever is pulled in.

 

[IG.]

Uhhhh no. Retarded timing does not delay the fuel "shooting" like u said. It delays the timing of the ignition spark by a few degrees.

Oops! I think I meant the ignition.

 

[kml]

Uhhhh no. Retarded timing does not delay the fuel "shooting" like u said. It delays the timing of the ignition spark by a few degrees.

I find if there is too much ignition spark my timing goes all retarded and I shoot my fuel too soon.



cheers
ken

 

[illuminati]

Well don't shoot all your fuel out at once!!!!

 

[Assassin8]

I am just trying to understand something. We all know that when the clutch is pulled with PC on the bike, the RPM goes a bit down, and when the clutch is releases the RPM goes a bit up.

Same could be said about the dealer mode. Since I installed the switch, it's easy to switch to the dealer mode. So, if the bike idles and I switch to the dealer mode, RPM goes up. And actually, if anyone dares to ride while in dealer mode, the bike acts a lot more aggressively at least in lower gears.

What I don't understand is how it's done. The throttle is in the same position, so the throttle bodies have the same opening. Obvious answer would be that the PC reduces amount of fuel injected for the RPM to drop. However, wouldn't that cause the lean issue?

And in order to increase RPM, would more fuel really do it? Wouldn't the mix become too rich?

So, all in all, just how the heck PC or ECU can control RPM for the same throttle opening?

I've just posted exactly the same issue... I know this is an old thread, but did you ever find out the reason it did this ?

 

[Assassin8]

I find if there is too much ignition spark my timing goes all retarded and I shoot my fuel too soon.



cheers
ken

That doesn't make any sense !!

 

[Bumblebee]

I've just posted exactly the same issue... I know this is an old thread, but did you ever find out the reason it did this ?

IG hasn't been on the forum since 2015 according to his profile, mostly these old threads are good for tombstone information...

You'd be better served to await some help on the thread you started.

I noted there was a response and that response made sense to me, these bikes are very sensitive to voltage.

 

[Assassin8]

IG hasn't been on the forum since 2015 according to his profile, mostly these old threads are good for tombstone information...

You'd be better served to await some help on the thread you started.

I noted there was a response and that response made sense to me, these bikes are very sensitive to voltage.

Yes, got that… cheers…

 

[Berlin Germany]

I am just trying to understand something. We all know that when the clutch is pulled with PC on the bike, the RPM goes a bit down, and when the clutch is releases the RPM goes a bit up.
(...)

jepp - thats what all so called g-packs do

simple solution (i guess you have a busa from ´02-´07)

get the ecu flashed to remove the speed limit in 6th gear and thus also the usual power limit in 2nd and 3rd gear.
thatfor you need a friend with lots of experience in that job
who owns the (free) software from "PetriK" and the interface from "smithabusa".
sametime you can rip out the g-pack an leave it at the crap box.

after that flashing a speedo with 220 mph can be installed