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General Category => General Discussion => Topic started by: YellowDuck on June 02, 2025, 09:05:59 AM

Title: Speedo correction, V7 850
Post by: YellowDuck on June 02, 2025, 09:05:59 AM
The speedometer on my 2023 V7 stone (LCD instruments) reads about 8% high, even on the original tires.  Has anyone successfully installed one of those correction do-dads that plug into the harness?  I can't find one that is specifically offered for the V7, but there are some universal ones available that in theory can be installed with some extra work.  I'd like to know if anyone has succeeded at that.

Also it would be great to know where the connector is on the bike - maybe in the headlight nacelle?

Feel free to comment that a properly operating speedo is not something I should worry about, but note that that is not actually my question :)
Title: Re: Speedo correction, V7 850
Post by: Dirk_S on June 02, 2025, 09:43:08 AM
I thought all moto speedometers were meant to be off that much to make you feel like you’re going faster.
Title: Re: Speedo correction, V7 850
Post by: Alfetta on June 02, 2025, 09:51:22 AM
ALL of my Fiats and ALL of my Alfa Romeo's, seem to indicate higher than actual speed...  I think its just an Italian thing !
Title: Re: Speedo correction, V7 850
Post by: n3303j on June 02, 2025, 10:02:48 AM
If measured distance and indicated speed are both off by the same amount a "corrector" could work. But if the indicated speed is the only error then corrector will mess up measured distance.
Title: Re: Speedo correction, V7 850
Post by: DoubleGuzzi on June 02, 2025, 10:22:01 AM
I'm sure that this ground has been covered many times before..
It's deliberate by all manufacturers (in EU/UK market) and can be up to 10%. Under-reading is not allowed.  :copcar:

I very much doubt that electronic speedos are calibrated to read true mileage travelled - that would require extra coding work.  :wink: So... when you go to sell your steed, a 10,000 mile bike may have only done 8,000 miles.  :shocked:
Title: Re: Speedo correction, V7 850
Post by: Moparnut72 on June 02, 2025, 10:29:57 AM
Correct the measured mileage is pretty damn close, so adjusting speed is probably not the best idea. My Mandello is off by about the same 9%. I have read that it is a European thing. I use a cell phone speedometer app. I put the phone on a handlebar mount. I got tired of converting speeds. It is easy to figure in the error but then adding in cop tolerance is a pain in the butt. The app I use is "GPS Speedometer: Speed Tracker" in the Google Play Store. It is free but usually an ad at startup.
kk
Title: Re: Speedo correction, V7 850
Post by: Dukedesmo on June 02, 2025, 10:33:09 AM


Quote from: DoubleGuzzi on Today at 04:22:01 PM (https://wildguzzi.com/forum/index.php?topic=123255.msg1902917#msg1902917)
I'm sure that this ground has been covered many times before..
It's deliberate by all manufacturers (in EU/UK market) and can be up to 10%. Under-reading is not allowed.  :copcar:
___________________ ___________________ _________

Obviously no EU regulations back then but my LM2 speedo is more than 10% 'optimistic'.   :laugh:

Both my Ducatis are pretty much spot on speedo-wise but that's because they've both got aftermarket digital speedos that can be calibrated accurately and my cars are both within 1mph (over-read) of actual speed.
But yes the regulations (UK/EU) are a tolerance of +10% / -0%

Title: Re: Speedo correction, V7 850
Post by: DoubleGuzzi on June 02, 2025, 10:45:23 AM
I did word my reply carefully!
My mechanical Duc M600 under-read considerably and even a change of speedo didn't improve matters. Just as well I didn't thrash it ALL the time.
Our German 4-wheeler is very close to true speed, comparing with roadside active signs.

UK police have a discretionary speed tolerance (which varies by region and limit set). Add this to the notional up to 10% speedo error, then it begins to explain why so many people drive/ride at around 80mph in a 70mph zone. At lower limits, IME, there are more 4-wheelers that speed than two.. the 50mph everywhere brigade, in particular.  :undecided: I digress.  :blank:

[GPS provides an average speed, over admittedly a relatively short distance -unless it is of military/intelligence grade.]

Oh, and on this subject.. the bloody speedo sensor is playing silly buggers on my Breva again! Outrageous rip-off for a new simple hall effect sensor.
Title: Re: Speedo correction, V7 850
Post by: kingoffleece on June 02, 2025, 12:22:13 PM
Or, one could just calibrate their own internal processor and be done with it.
Title: Re: Speedo correction, V7 850
Post by: bronzestar1 on June 02, 2025, 12:44:27 PM
Or, one could just calibrate their own internal processor and be done with it.

 :bow:  Yup, that would be the easiest solution for sure! 
Title: Re: Speedo correction, V7 850
Post by: YellowDuck on June 02, 2025, 01:03:30 PM
Okay so far this has been interesting but not at all helpful  :wink:

I guess I'll be the guinea pig and hunt around the harness for the appropriate connector.

Does anyone at least know if there are any connectors located in the headlight nacelle?  Also, does the speed get sensed off of the front wheel or the back?  I feel confident it is not off the sprocket.  :grin:
Title: Re: Speedo correction, V7 850
Post by: Clifton on June 02, 2025, 02:06:42 PM
What I have found interesting on every motorcycle I've owned with an optimistic speed display, that also has an "average speed" display built in, the average speed is correct.
Set your bike at an actual 70 mpg on level with cruise (the speedo may read 76). Toggle to the "average speed" display, reset it, and it will display 70 mph not the speedometer's 76.
Title: Re: Speedo correction, V7 850
Post by: Kiwi_Roy on June 03, 2025, 07:20:46 PM
The speedo on my V7III Special over-read by a similar amount.
I was able to install a larger rear tire and it bought the speedo right in line.
I installed Avon Roadrider Mk II tires made in the UK
Front Avon Roadrider Mk II140/80 V17
Rear Avon Roadrider Mk II 100/90-18 this barely clears the drive tunnel, by just over the thickness of a credit card.
I have been very pleased with these tires, I will try to source the same next time.

Note: I'm running Tubeless front and rear.
Title: Re: Speedo correction, V7 850
Post by: averb on June 03, 2025, 09:59:19 PM
It is not a "European thing" but a "United Nations" thing, UN Regulation No39, but USA and Canada are not party to the agreement
Title: Re: Speedo correction, V7 850
Post by: Huzo on June 03, 2025, 11:12:55 PM
I have bumped an old thread regarding work on this topic.
As usual most people went nowhere near answering the question, but gave me their unsolicited opinion as to the worth of such an exercise. I got the indicated and GPS displayed speed perfectly correct by making a new tone wheel with a different number of slots, but then the gear indicator would not read above 5.
Title: Re: Speedo correction, V7 850
Post by: Dr. Enzo Toma on June 04, 2025, 01:33:46 AM
Huzo, could you provide a link to that thread here instead?

That way if it ever gets buried again (it will), people can refer back to it more easily.
https://wildguzzi.com/forum/index.php?topic=103682.msg1903057#msg1903057
Title: Re: Speedo correction, V7 850
Post by: Huzo on June 04, 2025, 06:49:09 AM
I still reckon a front tone wheel with the same correction factor would do the trick.
One day I might get around to it, but lately I’ve been considering removing the motor and having the black paint removed by dry ice blasting then done in silver like the rear drive.
That’d look good I reckon.
I don’t know how to atttach a link.
Title: Re: Speedo correction, V7 850
Post by: SIR REAL ED on June 04, 2025, 07:20:27 AM
Or, one could just calibrate their own internal processor and be done with it.

But some people don't have the math gene!  I forget which ones do and which ones don't at the moment....
Title: Re: Speedo correction, V7 850
Post by: YellowDuck on June 04, 2025, 07:28:01 AM
I have bumped an old thread regarding work on this topic.
As usual most people went nowhere near answering the question, but gave me their unsolicited opinion as to the worth of such an exercise. I got the indicated and GPS displayed speed perfectly correct by making a new tone wheel with a different number of slots, but then the gear indicator would not read above 5.

Thank you for posting something relevant to the question!

Your result re: the GPI seems odd.  If the bike now thinks it's going slower at a given rpm, shouldn't it calculate that you are in a higher gear, rather than a lower one?

Anyway, I'll read the old thread...
Title: Re: Speedo correction, V7 850
Post by: Dirk_S on June 04, 2025, 07:39:28 AM
Thank you for posting something relevant to the question!

The yellow duck is a sassy one!

Be thankful you didn’t ask this question on Facebook. You’d still be scrolling through irrelevant photos of other people’s bikes or queries as to where you got your accessories.
Title: Re: Speedo correction, V7 850
Post by: Moparnut72 on June 04, 2025, 09:06:38 AM
I don't do Facebook except to keep up, kinda, on our regional boat racing page. Then again even it is full of irrelevant BS.
kk
Title: Re: Speedo correction, V7 850
Post by: DoubleGuzzi on June 04, 2025, 04:03:38 PM
.. even it is full of irrelevant BS.
Like local diners and 4-wheeler crap?  :evil:
Title: Re: Speedo correction, V7 850
Post by: Huzo on June 04, 2025, 07:49:45 PM
The yellow duck is a sassy one!

Be thankful you didn’t ask this question on Facebook. You’d still be scrolling through irrelevant photos of other people’s bikes or queries as to where you got your accessories.
Lucky they don’t charge for advice, you’d have to say to put it on your bill…! :grin:
Title: Re: Speedo correction, V7 850
Post by: YellowDuck on June 05, 2025, 10:03:08 AM
Lucky they don’t charge for advice, you’d have to say to put it on your bill…! :grin:

  :rolleyes: And here I thought you were actually cool.