V85 Speedometer inaccuracy

[Xlratr]

Xlratr..
Did you happen to read this post ?

Yep. I replied on 11. December.

[Huzo]

  Question, If it's on the centerstand, key on, not running and as you rotate the rear wheel by hand and run up through the gears does the indicator show properly?

     Paul B

Hmm..
Dunno mate, but I’m gunna’ get up, take a piss and wander out to have a look.
Keep asking diagnostic based questions, I love ‘em.
Another thing ..
If you have an unmolested system on your V85 that works and you change to a different tyre and do a recalibration, you do not inherit a gear position indicator problem.
Now why is that ?
After all, when you alter your tyre size, all the sensor knows is that you’ve changed the pulses per second and a recalibration brings it all back to normal. All I did from the point of view of the CPU is to do the same thing...
The waters are becoming muddied here for me.
Unless some miracle occurs, I’m going to have to make a front one. Now everything is set up tooling wise, it’s probably about 8 hours..
I just thought I was more or less finished.. 

[Huzo]

Yep. I replied on 11. December.

So you damn well did mate..
My apologies to you..

[Huzo]

  Question, If it's on the centerstand, key on, not running and as you rotate the rear wheel by hand and run up through the gears does the indicator show properly?

     Paul B

I just checked that Paul.
When the bike is on the centrestand, key “on”, not running.
The only gear indication you get is the “N” for neutral, cycling up and down through the ‘box rotating the wheel by hand, does not give a gear indication at any point.
Can anyone with a standard (unmolested) V85, do a similar test ?

[rtbickel]

No, it does not display anything but neutral with the key on, but I just reinstalled the rear wheel after fixing a flat so there may be something else involved with that.  Will report back after I take a ride.

[Huzo]

No, it does not display anything but neutral with the key on, but I just reinstalled the rear wheel after fixing a flat so there may be something else involved with that.  Will report back after I take a ride.

Thank you mate..
Will await your report.

[rtbickel]

After a quick spin around the block, it doesn't display anything other than neutral with the engine off.

[Huzo]

After a quick spin around the block, it doesn't display anything other than neutral with the engine off.

Thank you. That’s comforting information, it all combines to form knowlege based informed opinion.

[GonzoB]

Hmm..
Dunno mate, but I’m gunna’ get up, take a piss and wander out to have a look.
Keep asking diagnostic based questions, I love ‘em.
Another thing ..
If you have an unmolested system on your V85 that works and you change to a different tyre and do a recalibration, you do not inherit a gear position indicator problem.
Now why is that ?
After all, when you alter your tyre size, all the sensor knows is that you’ve changed the pulses per second and a recalibration brings it all back to normal. All I did from the point of view of the CPU is to do the same thing...
The waters are becoming muddied here for me.
Unless some miracle occurs, I’m going to have to make a front one. Now everything is set up tooling wise, it’s probably about 8 hours..
I just thought I was more or less finished.. 

The gearing is the ratio of the engine speed to the rear wheel speed, and by just changing the tyre size you don't change that. The ABS and traction control need to know about the actual speed, so they need re-calibration

I suspect that you may be out of luck with fixing the gearing unless there is a "re-calibration" for that (as items like the Healtech unit have).

Congrats, by the way.

Gonzo

[Huzo]

The gearing is the ratio of the engine speed to the rear wheel speed, and by just changing the tyre size you don't change that. The ABS and traction control need to know about the actual speed, so they need re-calibration

I suspect that you may be out of luck with fixing the gearing unless there is a "re-calibration" for that (as items like the Healtech unit have).

Congrats, by the way.

Gonzo

Oh dear..
I’m afraid that makes enough sense to worry me.
As you say, even if I put a new tone wheel on the front, it’ll have nothing to do with the rpm/rear wheel speed relationship.
I did not think of that..
Thanks...(I think)

[Moparnut72]

I don’t recall suggesting that the bike has to be moving to indicate a gear selection.
If y’all have a look at the bottom shot in post #184, you’ll see that with the bike on the centrestand and the rear wheel turning, the gear indicator correctly shows 1st gear.
In this case the bike knows it’s stationary because the front wheel is still.
Oddly though, why does the TC allow this condition, how does it know that I’m not doing a burnout in the grass and prevent me ?
I tried to spin the rear wheel the other day in the grass and was understandably prevented by the TC.

Excellent work. Your question sure opens another can of worms. The Harley I had used road speed vs rpm to indicate what gear I was. Pull the clutch lever and the display would go blank. My Audace shows what gear the gearbox is in no matter what, even if the engine has stalled. I would also be interested to see how the two different tone rings affect the ABS. I would be careful testing though. Would the ABS kick in early limiting braking effect? Very interesting work.
kk

[Kiwi_Roy]

Too bad the gear indication is not working.
Since it works by comparing the ratio of engine speed to wheel pulse rate
You have increased the wheel pulse rate
Just as an experiment try slipping the clutch a little to change the ratio back.
I'm not suggesting this as a fix but it might be enough to move the indication to 6
Would it then move back to 5 when you let the clutch out or is there enough differential in the calc to stay on 6?

[Huzo]

Too bad the gear indication is not working.
Since it works by comparing the ratio of engine speed to wheel pulse rate
You have increased the wheel pulse rate
Just as an experiment try slipping the clutch a little to change the ratio back.
I'm not suggesting this as a fix but it might be enough to move the indication to 6
Would it then move back to 5 when you let the clutch out or is there enough differential in the calc to stay on 6?

Remember I reduced the number of slots so I have reduced the pulse rate.
However your thought experiment is worthy of consideration.
If I go along in sixth, I will currently see 5 th on the panel, because the engine is revving higher than it should for that rear wheel rpm.
If I pull in the clutch and gently bring the revs down about 600, you’d think the indicator would sense a lower rpm for that wheel speed and throw a 6 th gear indication..
Hmmm...

[Huzo]

If the selected gear is deduced by comparing engine rpm to rear wheel rotation, why does the gear number not change if you pull in the clutch in say, third at 4,00 revs and let the rpm drop so that you have a lower rpm for the same rear wheel speed?

[Moto]

If the selected gear is deduced by comparing engine rpm to rear wheel rotation, why does the gear number not change if you pull in the clutch in say, third at 4,00 revs and let the rpm drop so that you have a lower rpm for the same rear wheel speed?

Because the ECU may understand that you pulled in the clutch. It does monitor that voltage. And it's only one additional "if clause" in the program needed to check the clutch status before changing its mind about what gear you're in.

By the way, I didn't pay any attention to this thread until yesterday. Quite impressive!

Moto

[Huzo]

Because the ECU may understand that you pulled in the clutch. It does monitor that voltage. And it's only one additional "if clause" in the program needed to check the clutch status before changing its mind about what gear you're in.

By the way, I didn't pay any attention to this thread until yesterday. Quite impressive!

Moto

I’m actually becoming more interested than I thought I would..
Regardless of the ultimate outcome, it’s actually a bit of fun. Thanks for your input.
Beetle was not optimistic from the start about this. He knew that there’d be hurdles to overcome that would be beyond the scope of what can be achieved with the ECU that we have in the ‘85.
I’ve done ok with my nuts and bolts approach, but there’s going to be a wall that I’m not good enough to climb.
Even if you could fool the tachometer by 6%, you’re then going to have erroneous readings on the panel.

[beetle]

I'm not sure the ECU crunches the numbers for the gear indicator. The Cali 1400 has a gear position gizmo on the gearbox, as does the Aprilia RSV4. Mayhap the 7SM doesn't have code required. It's possible the V85 dash does all the crunching for the gear indicator. We don't know what data is transmitted over the CAN bus, so would wait until you've got the front tone wheel in before you give up hope.

[Huzo]

I'm not sure the ECU crunches the numbers for the gear indicator. The Cali 1400 has a gear position gizmo on the gearbox, as does the Aprilia RSV4. Mayhap the 7SM doesn't have code required. It's possible the V85 dash does all the crunching for the gear indicator. We don't know what data is transmitted over the CAN bus, so would wait until you've got the front tone wheel in before you give up hope.

Oh...OK then...?
Now that HAS got my attention.
You think Beetle, that knowing these things as you do, coupled with a bit of a gut feeling, that my continuing on and doing a front one may be worth my while..?
I would happily do the work on your say so alone with no further prompting required.
I’m not even after a tentative guarantee, I’m emboldened to continue given your ponderings.
Thank you for caring.

[Huzo]

Just in the interests of gathering information..
Does anyone know how the system gathers the reading for the tachometer?

[beetle]

Just in the interests of gathering information..
Does anyone know how the system gathers the reading for the tachometer?

Phase sensor -> ECU -> Dash

[Moparnut72]

Just in the interests of gathering information..
Does anyone know how the system gathers the reading for the tachometer?

Wouldn't that come from the crank sensor?
kk

[Huzo]

Phase sensor -> ECU -> Dash

Ok.
Still over my head but now I know..
Thank you.

[Huzo]

Well..Here’s the good news.



Y’all have seen that before.
Here’s the other bit of good news
This turned up..


So something to do when the bike cools down. But why is the bike so hot I hear you ask ?
Because I went for a GPS measured 100 km trip and a 78 km trip.
100 GPS measured km=91 on the trip meter....9% error
78   GPS measured km=72 on the trip meter....8% error (give or take)
That I think is not really acceptable and unless someone REALLY knowledgeable (yes HIM) says otherwise, I can’t see building a front tone wheel will make a scrap of difference to this particular problem.
Beetle’s sage advice regarding building a front tone wheel to talk some sense into the gear indicator is totally acceptable, but you can all see that there is more at stake than just that.
Even if you just said “bugger it all I’ll wear it”, you still have the problem that the service intervals will blow out by 8 or 9%, the gear selection indicator is not quite right (although probably would be by then) but worst of all from my perspective, the distance to empty function will be very unreliable.
As for the indicator, pulling the clutch erases the numeral so you cannot go up to 6th and crack the clutch allowing the revs to drop 500 or so and observe if the system is “fooled” enough to indicate 6th.
I guess I could disconnect the switch so the system didn’t know and run the experiment, but God only knows what secondary issue that would throw up.
I will leave the new tone wheel on for the short term, but if there are no developments, I think I’ll remove it. I do not want to savagely root up that distance to empty or service interval indicator.

[Moto]

Disappointing.

Though I see that the new rear tone wheel could be responsible for the too-low trip odometer value, I have one question that I didn't see answered: Was the trip odometer measurement essentially accurate with the original tone wheel?

Moto

[RinkRat II]

 
  Interesting results, I would think the offsets would have fallen in the six percent category, but it could come back in line with another tone wheel if the computer sees similar rotation for normal operation. Nothing to lose at this point except some steel and labor. My $.02

      Paul B

[Huzo]

Disappointing.

Though I see that the new rear tone wheel could be responsible for the too-low trip odometer value, I have one question that I didn't see answered: Was the trip odometer measurement essentially accurate with the original tone wheel?

Moto

Don’t know, but I will find out.
How are others’ instruments performing ?

[Huzo]

 
  Interesting results, I would think the offsets would have fallen in the six percent category, but it could come back in line with another tone wheel if the computer sees similar rotation for normal operation. Nothing to lose at this point except some steel and labor. My $.02

      Paul B

Because the two tyres are different diameter but the slots are the same, the brain is at ease with different pulse rate from either end.
Seemingly the calibration does this, I did another this morning.
However, I’m thinking that with a successful calibration that it now has, the braking reads less slots in one rear wheel rpm, so would therefore think the wheel has only done 94% of the distance down the road that it actually has, that’s what has reduced the speedo reading back to correctness, but the down side is the odometer reading goes with it.
If speed = distance/time then I guess what we are seeing is that an alteration in indicated speed with time as a constant, distance must vary with speed...(unfortunately).
It’s going to need the 48 slot wheel in the back to get the odometer correct I think.
Leaving the 45 in the back and adding a 45 to the front will likely achieve nothing that an on board re calibration cannot accomplish.
Bum...!

[Huzo]

Disappointing.

Though I see that the new rear tone wheel could be responsible for the too-low trip odometer value, I have one question that I didn't see answered: Was the trip odometer measurement essentially accurate with the original tone wheel?

Moto

I remember doing a 100 k run against the GPS and from memory was about 1.5% out with standard tone wheel.
123.5 GPS equaled 122.0 indicated on trip meter.

[Xlratr]

Ah, I forgot to mention that. If you adjust the number of pulses for the Speedo by 6%, then the odometer will read 6% less. There's only one source for the signal so you have to choose what's more important to you. Speedo accuracy or odometer accuracy.
From the factory, the odometer is usually quite accurate, but the  Speedo intentionally reads too high. Trouble is, they depend on the same input. (Assuming the V85 works the same as the 5AM ECU)

Just sayin'.  ;-)

[Huzo]

Just sayin'.  ;-)

You could not possibly have been more correct..