Gen II Busa speedometer vs GPS readings

I am finding the Gen II Busa speedometer readings to be fairly typical of big-bore Japanese machines... readouts are optimistic across the range, with the margin of error increasing the faster one travels.

Went out today and took a few measurements at different speeds, comparing the stock speedo to a GPS in my tankbag's map-case. Here's some of the readings, they are not too surprising.

All figures are in mph.

Indicated - Actual

25.0 ------- 22.8

35.0 ------- 33.1

43.4 ------- 40.0

54.0 ------- 50.0

59.6 ------- 55.0

65.0 ------- 60.0

75.1 ------- 70.0

81.5 ------- 75.0

109.7 ------ 100.0

Looks like I can stay fairly close to 75-77 mph indicated on the interstate, and not have to sweat things.

Still, I need to be realistic about things; am still going to wire up my Valentine One well before next summer....

I note that you omitted the fact that these readings were taken by a professional rider on a closed course, with the disclaimer that watching your speedo and your GPS simultaneously while riding should only be attempted by trained professionals. Just covering your ass...

Warchild said:

Indicated - Actual25.0 ------- 22.8

35.0 ------- 33.1

43.4 ------- 40.0

54.0 ------- 50.0

59.6 ------- 55.0

65.0 ------- 60.0

75.1 ------- 70.0

81.5 ------- 75.0

109.7 ------ 100.0

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What happens when you take it up to 2nd gear??
a little under 10% -seems pretty typical for most jap bikes and identical to my zukis.

Get a yellr box or speedo healer and then you wont be adding almost 10% more miles than you really are.

Wicked Webby said:

get a yellr box or speedo healer and then you wont be adding almost 10% more miles than you really are.

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Nice find, WW!: SpeedoHealer I thought this was something only a dealer could calibrate (I've noticed ~3-4 MPH over the GPS reported speed on my FJR). Good to see someone being creative and taking matters into their own hands!

Wicked Webby said:

get a yellr box or speedo healer and then you wont be adding almost 10% more miles than you really are.

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Not the case ....at least speaking for many jap bikes ...and in particular Suzukis
I'd bet both my nuts that the odometer on the busa is fairly accurate.

-so you run into the problem: Do you want the speedometer accurate? or the Odometer accurate? ...because if you use a yellow box to fix the speed, it will throw the odometer off.

What does this poor engineering prove? It proves that it is no accident that the jap bike manufacturers want you to believe you're going faster than you are. Huge disservice IMO that they don't sync the odometer and speedometer.

RenoJohn said:

Wicked Webby said:

get a yellr box or speedo healer and then you wont be adding almost 10% more miles than you really are.

Click to expand...

Not the case ....at least speaking for many jap bikes ...and in particular Suzukis
I'd bet both my nuts that the odometer on the busa is fairly accurate.

-so you run into the problem: Do you want the speedometer accurate? or the Odometer accurate? ...because if you use a yellow box to fix the speed, it will throw the odometer off.

What does this poor engineering prove? It proves that it is no accident that the jap bike manufacturers want you to believe you're going faster than you are. Huge disservice IMO that they don't sync the odometer and speedometer.

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Reno J,

Well they make the speedo's read fast for liability reasons. It is not poor engineering. It is for tire speed rating discretions, possible consumer crash excuses and all those lawyers, law suites and such.

If your speedo is reading faster so is your ODO. Period. Using a speedo healer or Yellr box will not make your ODO incorrect. It will make it CORRECT.

The only second clock that the FJR(or any bike) has is if it has a ABS system... And that clock is set at the true speed not faster. And this clock is only in place to calculate the difference between your speedo and your true speed for ABS stopping reasons of course. Actually, it really isn't a second clock but a set value(the FJR's is 5%) that the ABS system uses against your speedo to compute stopping against a skid. You can test this too if you don't believe me! When you install a Yellr box on a ABS FJR you will only be able to set it to slow the speedo by -5%. Thats how it is setup(how fast it reads) from the factory. If you try to set it to read slower than -5% the ABS clock will automatically re-adjust itself back to the original speedometer error of +5% on the speedo. Even if you tried to reduce the speedo by -33%(yellr box allows this much plus/or minus) it re-calculates itself. Thus, you can reduce the error of reading fast by -5%.

I have changed many, many sprockets on bikes over the years and then the speedo's have read +10-25% faster(when gearing for more acceleration) and the ODO's always seen to accelerate also. Thus, I have used Yellr boxes on on my rides for over 10 years now. I prefer the Yellr box over the speedo healers BUT that is just my personal choice. I have used them both. I like the simple more fine tuning ability of the Yellr box. I don't represent Yellr box BUT they have a great product:

https://www.blackrobotics.com/

You should research it some more and be careful what you bet... You must want to give away your nuts.. NO, I don't want them.. Nice try!!

WW

Wicked Webby said:

If your speedo is reading faster so is your ODO. Period. Using a speedo healer or Yellr box will not make your ODO incorrect. It will make it CORRECT.

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Sorry, NOT CORRECT. This has been covered in numerous other threads.

Althought the speedo and odo run off the same data, the speedo is typically biased 5-10% high while the odo is very close to correct. This "built in" bias is because of instrument certification regulations requried to sell vehicles in most countries.

These regulations typically require that the speedo NEVER read low and can read up to 10% high, so the mfgs split the difference and aim for about 5% high. But the regulations also require a +/- 2% (or so) odometer error so that consumer warranties (espeically emission warranties) don't expire prematurely. So if the mfgs make the odo consistent with the 5% speedo error, they'd be in violation of the regs. So they make the odometer more or less accurate. This results in the odd situation where there is a deliberate bias between the two instruments even though they use the same source data.

So if you mess with the calibration and get the speedo correct, your odo will probably read low. Which isn't a terrible thing for most folks.

None of us can speak to what the errors are on any particular bike sample, but this is the general way things work out of the box and has been confirmed by numerous people using GPS and timed roadside mileage markers.

- Mark

Wicked Webby said:

If your speedo is reading faster so is your ODO. Period.

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No, this is completely inaccurate.

There is one speed signal which drives both the speedometer and the odometer. However, the manufacturers make the display units such a way that the speedometers usually read high, while the odometers are quite accurate on stock vehicles.

Using a speedo healer or Yellr box will not make your ODO incorrect. It will make it CORRECT.

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No, it does not. Again, this is completely inaccurate.

Speedo to odo error ratio is the quotient of the indicated speed, and the speed which drives the odometer internally. This error ratio is fixed in the dashboard logic, i.e. it's bike model specific and will be constant no matter what you change on your bike. The speedo to odo error ratio is almost the same as the initial (factory) speedo error, considering that the odometers are usually accurate on stock vehicles.

You don't have to believe the above words if you don't want to. They are not mine; they are taken directly off the Speedo-healer web site. Specifically, this wording was lifted from Question #16 on their FAQ page.

As RenoJohn correctly observed, you can tune the Speedo-healer for *either* a perfect speedometer, OR a perfect odometer. But not both simultaneously. Typically, most install a Speedo-healer to obtain a perfect speedometer. Rarely does one install a Speedometer to get their odometers dead-nuts accurate. But it happens occasionally. Like last May, when I installed a Speedo-healer on my Blackbird to obtain a perfectly accurate odometer in preparation for BBG Hell Week. When I had the odometer calibrated perfectly against a DOT odometer course, my speedometer was 9% optimistic. But for that particular Endurance event, the odo was much, Much, MUCH more important than a speedometer.

When you install a Speedo-healer and adjust for accurate speedometer readings, then as Markjenn correctly observed, your odometer will now read artificially LOW. Which is a good thing for re-sale and warranty purposes.

I'd bet both my nuts that the odometer on the busa is fairly accurate.

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It is impressively accurate. Just when the GPS ticked over 10.0 miles, the Busa odometer displayed 10.1 miles.

Warchild said:

I'd bet both my nuts that the odometer on the busa is fairly accurate.

Click to expand...

It is impressively accurate. Just when the GPS ticked over 10.0 miles, the Busa odometer displayed 10.1 miles.

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Which extrapolates to an additional ~100 miles displayed on the odometer for every 10,000 actually ridden. Not enough to affect resale of the bike (by more than a buck or 2 tops), or be concerned enough with to spend ~$150 on a SpeedoHealer! (Unless of course, now that you know, it's one of those little things that you know just isn't quite right about your bike. And that little seed of knowledge just sits there and festers and festers until it becomes something really, really irritating and you start yelling at your dealer and blaspheming the manufacturer and then putting up posts about starting a class action and getting the advice of lawyers... Damn, I hate that little insidious ECU with its Altitude Surge all coiled up just waiting to strike like a... ****. What were we talking about again?? )

Wicked Webby said:

Reno J, If your speedo is reading faster so is your ODO. Period.

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I'll say this as politely as I can: Bullpoop. They are NOT sync'd as we'd all assume and hope that they would be. Fix one (speed or odometer) with your choice of pulse altering devices, the other will change by the same margin of error.

Wicked Webby said:

You should research it some more and be careful what you bet... You must want to give away your nuts.. NO, I don't want them.. Nice try!!

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My bet is a safe one ..........and I'd welcome your condecending attitude in our next poker game ...Mama needs new shoes LOL LOL

Well guys,

This is news to me... When I went down one tooth up front on my zx10r the speedo and odo changed drastically. The speedo was reading over 15% higher than actual. After I dialed it down with the Yellr box the speedo was dead on. BUT I never tested the ODO....HMMMM... So what your saying is the odo was correct and after the sprocket change was only reading 7-8% high because of the sprocket change(and was set correct from the factory, even though the speedo was reading 7% high) and not the 15% as the speedo was reading? Interesting theory... Now I am more than curious. When it warms up, I will test them both against my GPS for ODO's results and see what I am getting for 10 miles also. I know my speedo's are dialed in correctly.

More to come...

BULLPOOP! Hahahahahah!

WW

Wicked Webby said:

When it warms up, I will test them both against my GPS for ODO's results and see what I am getting for 10 miles also. I know my speedo's are dialed in correctly.

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Please come back here and report. I love storing these little factoids in my trivial mind.

Wicked Webby said:

BULLPOOP! Hahahahahah!

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Bovine feces?!?!

Interesting reading here. I ran into the same problem when correcting the speedo after a sprocket change on my literStrom. I added two teeth to the rear sprocket to make 6th gear a little more usable. Now the speedo was wildly inaccurate. Added a healer to the bike and dialed in a 12.5% correction. The speedo is dead nuts accurate now, but...the odometer is almost 10% slow after repeated runs against the DOT mile markers.

--G

escapefjrtist said:

Interesting reading here. I ran into the same problem when correcting the speedo after a sprocket change on my literStrom. I added two teeth to the rear sprocket to make 6th gear a little more usable. Now the speedo was wildly inaccurate. Added a healer to the bike and dialed in a 12.5% correction. The speedo is dead nuts accurate now, but...the odometer is almost 10% slow after repeated runs against the DOT mile markers. --G

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Yep, you got it. Even without the gearing change that you made, your experience is consistent with most Japanese bikes. My first strom I put on a yellow speedo healer but I wired the speedo healer with a toggle switch so that I could instantly swap between accurate speelometer OR accurate odometer. Seemed cool at the time, and maybe a good option for some,
...but on the next bike I went with a seperate speedocomputer(typical of what many use) to give an accurate speed rating.



This will give you accurate speed, accurate odometer and a host of other data .....many options out there from simple bicycle computers to elaborate dual-sport devices. Perhaps a good option for some. I like it.

may folks use these, i *think* I recall seeing a like device on Warchilds Blackbird?

The most common "fix" is to do nothing ...the odometer (assuming no gearing changes) will be relatively accurate and you just deduct aprox 10% (or a bit less) from your displayed speed. IE: 80MPH displayed = aprox 73MPH actual.

IMO a real shame that the manufactures don't sync the odometer and speedometer accurate to each other.

RenoJohn said:

IMO a real shame that the manufactures don't sync the odometer and speedometer accurate to each other.

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As discussed before, they aren't really allowed to by law.

- Mark

Wicked Webby said:

When I went down one tooth up front on my zx10r the speedo and odo changed drastically. The speedo was reading over 15% higher than actual. After I dialed it down with the Yellr box the speedo was dead on. BUT I never tested the ODO....HMMMM... So what your saying is the odo was correct and after the sprocket change was only reading 7-8% high because of the sprocket change(and was set correct from the factory, even though the speedo was reading 7% high) and not the 15% as the speedo was reading? Interesting theory... Now I am more than curious. When it warms up, I will test them both against my GPS for ODO's results and see what I am getting for 10 miles also. I know my speedo's are dialed in correctly. WW

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That's because YOU changed the dynamic of the speedo and odometer. Suzuki has long since been known to make the speedo read high while the Odometer was dead on accurate. Once the end user changes sprockets, all bets are off.

One solution that some Bandit riders were doing a while back was replacing the speedo dial face. Someone somewhere made an aftermarket speedo face cover that was accurate. Thus speedo and odo were now accurate without a yellow box.

markjenn said:

As discussed before, they aren't really allowed to by law.

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ya, that argument makes more sense than any I've seen ....yet the FJR and a (very) few handful of other bikes I've seen are pretty darn close .........

ponyfool said:

One solution that some Bandit riders were doing a while back was replacing the speedo dial face. Someone somewhere made an aftermarket speedo face cover that was accurate. Thus speedo and odo were now accurate without a yellow box.

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YA!! good call Pony! ....same with stroms and other bikes ...changing out the speedo dial face is a great solution.