Idea to fix Speedo error?

[SS4Luck]

So my Speedo is 5-8 fast at important speeds (45-80 ish)

Can I just swap the rear sprocket to bring it closer to being accurate? These bikes get speedo signal off the front wheel so I’m *hoping* a sprocket change will help bring the speedo closer but I never know with these things.

[SPECIALFORCESOFGOD]

I thought I was crazy. At 50-65, everyone is passing me...even scooters.

[Berlin Germany]

@SS4Luck
what bike? a busa or what ?
and if busa what type? gen1 , 2 , or 3 ??

[SS4Luck]

@SS4Luck
what bike? a busa or what ?
and if busa what type? gen1 , 2 , or 3 ??

Gen 3

[fallenarch]

Is there some reason why you can't use a speedo healer?

I use my GPS anyway

[SS4Luck]

I thought I was crazy. At 50-65, everyone is passing me...even scooters.

Yeah I did the same thing lol downloaded a GPS speedo on my phone and jumped on the freeway and was amazed how off it was.

IS there some reason why you can't use a speedo healer?

Speedo healer won’t work on gen 3, at least not yet. Too much in the computer is still locked.

[sixpack577]

Heal-Tech doesn't make a gen3 Speedohealer.
They were working on it earlier this year, but have since confirmed they will not be making a gen3 version.
Electronics work differently than gen1 or 2.
@smithabusa has posted info about this.

[SPECIALFORCESOFGOD]

Yeah I did the same thing lol downloaded a GPS speedo on my phone and jumped on the freeway and was amazed how off it was.

Hmmm...gonna try that then. For now, I do 10 over the speed limit and that seems to work whether at 25 or 55 MPH.

[Vanishing Point]

Next rear tire swap , put a 55 series on

[Got-Busa?]

Guys, it reads from the FRONT wheel so a sprocket change or rear tire swap will have no change.

Maybe try a different size front tire but it’s not worth the trouble, just get a quality GPS.

[SS4Luck]

Guys, it reads from the FRONT wheel so a sprocket change or rear tire swap will have no change.

Maybe try a different size front tire but it’s not worth the trouble, just get a quality GPS.

If the pcm doesn’t take RPM into its speedo calc from the front tire signal, than changing the sprocket or tire will change the bikes speed, it’s just gonna take some math to figure it out.




I’m putting a new swing arm on next week, I’m going to order a new sprocket that mathematically is closer and see what it does. Worst case I just end up with a cool black vortex sprocket.

[smithabusa]

If the pcm doesn’t take RPM into its speedo calc from the front tire signal, than changing the sprocket or tire will change the bikes speed, it’s just gonna take some math to figure it out.




I’m putting a new swing arm on next week, I’m going to order a new sprocket that mathematically is closer and see what it does. Worst case I just end up with a cool black vortex sprocket.

why would it need engine RPM? it reads speed coming from the front tire to drive the speedo only.

[SS4Luck]

Idk man, I’m coming from the car world where they do dumb poop like that all the time.

[LuapSouthFlorida]

why would it need engine RPM? it reads speed coming from the front tire to drive the speedo only.

Are you 100% sure on that?
IDK about Gen3 but both my Gen1 Busa's read speed using a sensor on the front sprocket.
Honestly I don't know, but want to

[smithabusa]

Are you 100% sure on that?
IDK about Gen3 but both my Gen1 Busa's read speed using a sensor on the front sprocket.
Honestly I don't know, but want to

Yes I am 115% sure, I have a couple hundred hours into the rabbit hole that is Gen3 Busa with my test bench in the basement. Never seen a Gen3 in person yet, but I am very much into the innerworkings of the ECU and dash etc as I am working to make the dash compatible with standalones (MaxxECU).

[smithabusa]

[smithabusa]

[LuapSouthFlorida]

Yes I am 115% sure, I have a couple hundred hours into the rabbit hole that is Gen3 Busa with my test bench in the basement. Never seen a Gen3 in person yet, but I am very much into the innerworkings of the ECU and dash etc as I am working to make the dash compatible with standalones (MaxxECU).

So currently the only way to correct the speedo is, as someone else said, put a different tire size on, which opens up a whole other can of worms.
I don't mind the error so much because i know about it and can adjust my speed accordingly. I'd be more concerned with the odometer showing more miles on the bike than there actually are

[smithabusa]

So currently the only way to correct the speedo is, as someone else said, put a different tire size on, which opens up a whole other can of worms.
I don't mind the error so much because i know about it and can adjust my speed accordingly. I'd be more concerned with the odometer showing more miles on the bike than there actually are

I haven't tested it yet, but I can about guarantee that the odometer reads correctly despite the speedo reading fast.

[LuapSouthFlorida]

I haven't tested it yet, but I can about guarantee that the odometer reads correctly despite the speedo reading fast.

IDK how that would be because a sending unit is a sending unit, but Hallelujah if that's the case. I ran a speedo healer on my Gen 1 bikes, and it worked great. Not available for Gen3.