V85 Speedometer inaccuracy

[Huzo]

My money says gear change indicator is reading the front tone ring and speedometer is reading the rear tone ring.  My "guess" is that the new tone ring will get the inputs back within spec.

Or, it could be an error totally unrelated to the new tone ring!  LOL!  Wouldn't that be funny.

Rocker, if that was true and I really hope it is, why has the alteration of the rear ring introduced the anomaly ?
The odo was acceptably good before this debacle. What is your reasoning to lead you to think this ?
How about if I start the bike, put it in gear on the centrestand..(yes I know but not for long), and see if the odometer begins to count kilometres.
Or conversely  to reduce the chance of re lighting an old thread, rock the front wheel off the ground, and spin the front wheel with my drill and check for odometer function ?

[Xlratr]

Rocker, if that was true and I really hope it is, why has the alteration of the rear ring introduced the anomaly ?
The odo was acceptably good before this debacle. What is your reasoning to lead you to think this ?
How about if I start the bike, put it in gear on the centrestand..(yes I know but not for long), and see if the odometer begins to count kilometres.
Or conversely  to reduce the chance of re lighting an old thread, rock the front wheel off the ground, and spin the front wheel with my drill and check for odometer function ?

You know that the rear ring gives the signal for speedo and odometer (because your new one has altered both). Speed plus engine rpm is all that is required for the gear indicator calculation. Why would Guzzi add complexity with a second speed input from the front wheel? That wouldn't make sense.
The purpose of the front ring will just be to establish if there is a sudden change in rotation speed between front and rear wheels to enable the ABS.
If making a new ring for the front fixes your gear indicator, I wouldn't be more surprised if I woke up tomorrow with my head sewn to the carpet (yes, I watched Christmas Vacation again!) 

[rocker59]

Guzzi

That wouldn't make sense.
 

'nuff said...   

[rocker59]

Rocker, if that was true and I really hope it is, why has the alteration of the rear ring introduced the anomaly ?
The odo was acceptably good before this debacle. What is your reasoning to lead you to think this ?
How about if I start the bike, put it in gear on the centrestand..(yes I know but not for long), and see if the odometer begins to count kilometres.
Or conversely  to reduce the chance of re lighting an old thread, rock the front wheel off the ground, and spin the front wheel with my drill and check for odometer function ?

I don't guess I have a logical reason for thinking this.  And, to be honest I was way off with what the new rear tone ring would accomplish.

Please be careful, if running the bike on the centerstand.  Probably best to just ride it!   

[Huzo]

I don't guess I have a logical reason for thinking this.  And, to be honest I was way off with what the new rear tone ring would accomplish.

Please be careful, if running the bike on the centerstand.  Probably best to just ride it!   

Yeah mate..
It would be diabolically foolish to keep going down a dead end track, even on a V85...!
I will spin the front with my drill and see if the k’s start to add.

[Huzo]

Started the bike on the stand and allowed it to idle in gear.
Odometer started adding k’s with (obviously) stationary front wheel.
I’m rooted

[GonzoB]

When you add the 6% under-reading change (due to the new encoding wheel) to the 1.5% existing under-reading of the ODO, you are pretty close to the 8% you measured.

Where I fitted the Healtech speedo healer to my previous ride, the ODO was over-reading by ~4% so when I corrected it with the -8%, it under-read by ~4% which was tolerable. 8% under probably isn't.

I suggest you find a local mate who's an Arduino nerd and get him to build an electronic solution. That's if the speedo still worries you....

Gonzo

[Huzo]

When you add the 6% under-reading change (due to the new encoding wheel) to the 1.5% existing under-reading of the ODO, you are pretty close to the 8% you measured.

Where I fitted the Healtech speedo healer to my previous ride, the ODO was over-reading by ~4% so when I corrected it with the -8%, it under-read by ~4% which was tolerable. 8% under probably isn't.

I suggest you find a local mate who's an Arduino nerd and get him to build an electronic solution. That's if the speedo still worries you....

Gonzo

Thanx Gonz, you are correct...
I think I will wait for Beetle. He will have a quiet word to the diodes and they will fall into line, if he can’t do it then I’ll not feel too bad that it was beyond me..
It was fun though..!

[RinkRat II]

      While your waiting for Beetle, swap the tone wheel front to back, go for a ride and see what you get. It may give you more clues to the solution.

         Paul B

[Huzo]

      While your waiting for Beetle, swap the tone wheel front to back, go for a ride and see what you get. It may give you more clues to the solution.

         Paul B

They’re different mate..Won’t fit.

[Huzo]

And so...
It was with a heavy heart and a slightly red face that our intrepid modifier undid the bolts and threw the useless tone wheel in the bin and strode toward the next exciting adventure, full of hilarious hijinx...


Sorry to lower the tone....  

[GonzoB]

Hey, with 253 replies you did well keeping us entertained.

Thanks.

Gonzo

[Huzo]

It was good fun Gonz.
What I did was successful, but the tip about the odometer was the one I should have heeded.
 Anyway...
I went out today with the original tone wheel back in and checked the odometer. It was only 1% off give or take so that’s a bonus. Also the ‘85 used 10 litres for 240 k, so 4.16 l/100 k
That doesn’t even sound right to me but that’s what it took and I did fill it right up...!

[Frenchfrog]

Well it was a noble effort...all credit to you ingenuity and persistence....have a good New Year !

[Huzo]

Well it was a noble effort...all credit to you ingenuity and persistence....have a good New Year !

Thanks mate..The speedo worked beautifully.
All in fun...

[Huzo]

Just before I lower this thread into a hole and start shovelling dirt on top...
Does the signal split to the speedo/odometer by a separate wire or more likely an electronic piece of wizardry ?
I ask because if the split in the signal was in the wiring, I could take the odometer signal from the front tone wheel and by making a new one with the requisite slots, bring the odometer back into line without buggering up the speedo.
I could then do a re calibration to fix the expected ABS/TC anomaly...

[beetle]

Nope. The signal is sent to the ECU from the ABS controller.  The ECU talks to the dash via CAN bus.

The only way would be to intercept the signal to ECU and interfere with it, or find the correction factor in the map and modify it.

[Huzo]

Nope. The signal is sent to the ECU from the ABS controller.  The ECU talks to the dash via CAN bus.

The only way would be to intercept the signal to ECU and interfere with it, or find the correction factor in the map and modify it.

Utterly beyond me..

[GonzoB]

Nope. The signal is sent to the ECU from the ABS controller.  The ECU talks to the dash via CAN bus.

The only way would be to intercept the signal to ECU and interfere with it, or find the correction factor in the map and modify it.

And, of course, if you were able to do either of those things there is still the probability that changing the speed readout by massaging the CAN speed signal or ECU map factor will change the odometer at the same time!

Gonzo

[Kiwi_Roy]

I followed this thread with interest, you did your best to resolve the error.
My new V7iii has a similar error, it must be in the software ECU or Dash, we should be demanding that Piaggio fix it.
To account for changes in the tire sizes it would be easy enough to have a fudge factor the owner could change.

[beetle]

I followed this thread with interest, you did your best to resolve the error.
My new V7iii has a similar error, it must be in the software ECU or Dash, we should be demanding that Piaggio fix it.
To account for changes in the tire sizes it would be easy enough to have a fudge factor the owner could change.

The speedo correction factor can be modified for the MIUG3. Knock yourself out.


Making demands on Piaggio would be fruitless. I think you'll find that the speedo error is well within Govt mandated specs in all countries.

[Huzo]

I followed this thread with interest, you did your best to resolve the error.
My new V7iii has a similar error, it must be in the software ECU or Dash, we should be demanding that Piaggio fix it.
To account for changes in the tire sizes it would be easy enough to have a fudge factor the owner could change.

Well they sort of have mate..
When I installed the new tone wheel, I introduced a 6% error into the system. It was 6.5% out @ 100 k and with the modification, it was 1%.
That means the on board re calibration function could handle 5.5% at least which is more than that required for a new tyre, but we all know what that did to the gear selector indicator and the odometer...(I was clearly warned).

[Huzo]

I think you'll find that the speedo error is well within Govt mandated specs in all countries.

Well..
I cannot comment on Lithuania or Uzbekistan, but in Australia...?
They shat it in..

[Kiwi_Roy]

The ADRules are BS, I'm sure most other countries have something similar thought.
In 1988 most speedometers worked by a magnet spinning around dragging a pointer, in this day and age speedometers are digital either with a digital display or analog pointer and stepper motor there is no reason to be out by 1% let alone 10$

[Kiwi Dave]

I don't understand the big deal.  I tend to cruise at around 10% over on the speedo, knowing that it reading fast, and so I can speed in safety.  Most of the police cars will just flash their headlights or beacons when they consider I'm getting too close to their acceptable tolerance. Radar detectors (legal in NZ) help with getting too carried away.

[Huzo]

I don't understand the big deal.  I tend to cruise at around 10% over on the speedo, knowing that it reading fast, and so I can speed in safety.  Most of the police cars will just flash their headlights or beacons when they consider I'm getting too close to their acceptable tolerance. Radar detectors (legal in NZ) help with getting too carried away.

The big deal is...
I WANT IT CORRECT...!
I don’t want to have to make on board re calculations that vary between 100 k’s and 50 k’s and all the other anecdotal  stories and conventional wisdom.
I just want it right...Please.

[Frenchfrog]

I totally get that...that's why I got the sygma...looks  out of place even though it is slightly discreet...but at least i know exactly how fast i'm going or not ! And it was only 40 euro which is the guzzi content....

[93spada]

So I might have missed this but...…..
How do you know your GPS is all that accurate.

[93spada]

https://www.gps.gov/systems/gps/performance/accuracy/

[Huzo]

So I might have missed this but...…..
How do you know your GPS is all that accurate.

I was banking on the assumption that it knows it’s position within 15 metres, which is the distance it travels before a recalculation, if I miss/ignore a command.
And..
The on board time clock is spot on.
So the calculation of distance/time (velocity), must carry the  same accuracy as the position...