Odometer reading
Seasoned HDF Member
Joined: Sep 2008
Posts: 14,061
Likes: 11,080
From: San Diego, CA
I would suspect that as long as the new ECM tables relating to mileage are set up for that particular bike, the range number should be as accurate as before the ECM swap...
I have found the range number to be close at times, and sometimes it's off by a good bit.... It can change rapidly if I start to play with the throttle...
It's just a guide anyways, nothing I would consider a concrete number...
Last edited by hattitude; Jun 30, 2022 at 09:18 AM.
Road Warrior
Joined: Sep 2021
Posts: 1,902
Likes: 1,349
From: Black Hills of SD
I think what he is asking is = If the ECM is changed with a new speedo or the speed that matched that ECM [ form another bike ], wouldn't that be a way to show incorrect [ lower ]milage?
But, I could be wayyyy off. Known to happen.
But, I could be wayyyy off. Known to happen.
Road Master
Joined: May 2021
Posts: 777
Likes: 928
From: North Carolina
Yes, that's pretty much what I was asking. However, that might be a very expensive way to lower the displayed mileage. I have no idea what a HD ECM cost.
Seasoned HDF Member
Joined: Sep 2008
Posts: 14,061
Likes: 11,080
From: San Diego, CA
Interesting question.... my bikes have the mileage in the speedo on two, and the other has a BCM... so not sure what part the speedo has on changing the ECM...
Prior to the BCM, there were a series of speedos (forget the years) where the speedo got the mileage from the ECM via a temporary cable connection...... Then you would install the speedo and drive for 25 miles. After 25 miles, they were permanently married.
I've never read about going the other way... changing the ECM and matching it to current mileage... or if it even needs that...
Someone will know/chime in with the procedure...
Last edited by hattitude; Jun 30, 2022 at 06:14 PM.
Road Warrior
Joined: Sep 2021
Posts: 1,902
Likes: 1,349
From: Black Hills of SD
I once had to change a circuit board on the CBR speedo module. Milage was started over at zero after that. I know it's not HD or apples to apples. But electronics can be adjusted, where there is a will there is a way.
For example, I have crashed HD that I am parting out. I also have a high mile super clean similar HD. I change out all the electronics, ECM, speedo panel, whatever it takes. - Walla, low milage super clean bike that I make a lot more $$$$ off. I bet it happens all the time in the flippers and parters world.
For example, I have crashed HD that I am parting out. I also have a high mile super clean similar HD. I change out all the electronics, ECM, speedo panel, whatever it takes. - Walla, low milage super clean bike that I make a lot more $$$$ off. I bet it happens all the time in the flippers and parters world.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Southpaw Super Glide: A Left-Hand-Drive 1979 Harley FXE Built to Fit the Rider
Verdad Gallardo
The Best and Worst Harley-Davidson Moves of 2025
Verdad Gallardo
Road Master
Joined: May 2021
Posts: 777
Likes: 928
From: North Carolina
I once had to change a circuit board on the CBR speedo module. Milage was started over at zero after that. I know it's not HD or apples to apples. But electronics can be adjusted, where there is a will there is a way.
For example, I have crashed HD that I am parting out. I also have a high mile super clean similar HD. I change out all the electronics, ECM, speedo panel, whatever it takes. - Walla, low milage super clean bike that I make a lot more $$$$ off. I bet it happens all the time in the flippers and parters world.
For example, I have crashed HD that I am parting out. I also have a high mile super clean similar HD. I change out all the electronics, ECM, speedo panel, whatever it takes. - Walla, low milage super clean bike that I make a lot more $$$$ off. I bet it happens all the time in the flippers and parters world.
Stellar HDF Member
Joined: Sep 2020
Posts: 2,418
Likes: 2,858
From: Southeast
I would suspect that as long as the new ECM tables relating to mileage are set up for that particular bike, the range number should be as accurate as before the ECM swap...
I have found the range number to be close at times, and sometimes it's off by a good bit.... It can change rapidly if I start to play with the throttle...
It's just a guide anyways, nothing I would consider a concrete number...
I have found the range number to be close at times, and sometimes it's off by a good bit.... It can change rapidly if I start to play with the throttle...
It's just a guide anyways, nothing I would consider a concrete number...
when I purchased a ThunderMax ECU for my 06 RKC, I got the "VIN ERR" message. The bike already had the H-D speedo/tach upgrade and I didn't want to get rid of that. They state to install the new VIN in the TMAX ECU and it should go away. If I'm remembering correctly, that didn't work.
I read up on the issue and while the exact process is a bit foggy now, I remember lifting the tank-mounted gauge pod and unplugging and plugging in the speedo/tach according to a specific process. I can't find that process on the 'net right now and I can't tell if it was a TMax thing or just the way H-D works. If I can come across that information again, I'll update my input. I at least wanted to note that a new ECU will need to be mated to the gauges, but it is possible. Hope it helps!
Last edited by Tcrafty; Jul 1, 2022 at 09:31 AM.