Speedometer Correction - Trail 125

[Southwest ORV]

Hello friends,
I see lots of discussion about sprocket changes to lower gearing. Someday when I get mine, I'm positive I'll do the same. But, with that comes inaccuracy with your speedometer and therefore odometer, correct?
Has anyone seen a solution for this? I have a thing about miles - I love to know how many miles I've put on my machine, and it would bug me to have a false reading.

 

[r80rt]

From what I read, and I can't prove any of it. The speedometer is roughly 2 to 3 m.p.h. off from the factory. With the lower gearing it's roughly 3 to 5 m.p.h off. If I change the oil a bit early because of it, that's fine with me, I never look at the speedometer anyway. There is supposed to be something on the market to correct this but I don't know what it's called, Speedometer Dr. or something like that. I've also read of some riders having the ABS show a fault with the lower gearing, I haven't. But if the ABS works or not I don't care, it's still acts as a normal brake and that's all I need. It works for me, but you may have different results.

 

[AZ7000']

Depends if the speed is read off the computer or the wheel rotations or a combo. My bigger tires probably changed it somehow...

My 1974 is my daily driver and I could care less about the odometer and if its off by a small percentage. I'll change the oil in her every few years and the 125 will definitely outlive me. I know and knew the excitement, ride and enjoy the heck out of it!!! Don't sweat the small stuff, got my first wear marks from the trailer and rubbing up on my dirt bike, bummed me out but adds character!

 

[Southwest ORV]

Depends if the speed is read off the computer or the wheel rotations or a combo. My bigger tires probably changed it somehow...

My 1974 is my daily driver and I could care less about the odometer and if its off by a small percentage. I'll change the oil in her every few years and the 125 will definitely outlive me. I know and knew the excitement, ride and enjoy the heck out of it!!! Don't sweat the small stuff, got my first wear marks from the trailer and rubbing up on my dirt bike, bummed me out but adds character!

View attachment 183

Yessir, there’s a story to go with each scar.

 

[Lostagain]

On the 2021 CT125 the speed input is from the area of the countershaft. Changing the front sprocket will create a speed error. You can fix that with a 'speed Dr' or an aftermarket instrument cluster which also includes tach, oil temp, correction for front or rear sprockets, and more. OPMID is working on a kit...https://opmid.co.jp/

 

[G19Tony]

All motorcycles are optimistic a little bit. I won't worry about. this bike won't go fast enough for the Police to bother with.

 

[Msfitoy]

I use the GPS nav speed on my phone mounted to the column...mounting 3.0-17 tires will screw things up too so GPS is the way to go if you really want to know the true speed...

 

[Lostagain]

I use the GPS nav speed on my phone mounted to the column...mounting 3.0-17 tires will screw things up too so GPS is the way to go if you really want to know the true speed...

Yes, still have an issue with odometer....not sure if I even care about the odo with the small mileage I anticipate putting on the LRD. Changing the oil once a year will be overkill.

 

[Southwest ORV]

I get a kick out of knowing, for example, that I have ridden enough miles on my quad to ride from here to Alaska. I know it's goofy, but that is why I like an accurate odometer. I'd love to see 10,000 miles on the CT's odometer someday (yes, I ride a lot) and not be thinking, "hmm, so 10,000 miles x .9 should be about right." Oh well. If there's no fix, there's no fix.

 

[Spydie]

On the 2021 CT125 the speed input is from the area of the countershaft. Changing the front sprocket will create a speed error. You can fix that with a 'speed Dr' or an aftermarket instrument cluster which also includes tach, oil temp, correction for front or rear sprockets, and more. OPMID is working on a kit...https://opmid.co.jp/

Opmid doesn't have the Dr. Speed ready until march for the CT125 and they aren't even sure if they'll ship it to the USA. I'm in touch with them almost daily. HardRacing.com doesn't have one to fit it either, but I'm working with them to try to get one. I sent them our wiring diagram today. My ABS fault light (and results in disabling the ABS) comes on in 5-10 miles of highway riding with a 13t front sprocket. Makes no difference if you change the rear Sprocket, if you are running the same gear ratio (3.00) you should get an error. Several people have reported it.

 

[Spydie]

I use the GPS nav speed on my phone mounted to the column...mounting 3.0-17 tires will screw things up too so GPS is the way to go if you really want to know the true speed...

If you want a correct speedometer, get the Opmid. It's adjustable and I have it set to my GPS

 

[ScooterD]

If you want a correct speedometer, get the Opmid. It's adjustable and I have it set to my GPS

Love the Opmid but have been having problems programing it. Got MPH according to iphone gps but cant get far enough in the programing to get Temp to F and tire sprockets Etc.

 

[Spydie]

Love the Opmid but have been having problems programing it. Got MPH according to iphone gps but cant get far enough in the programing to get Temp to F and tire sprockets Etc.

Remember there are two adjustments setups. Hold the button down for 3 seconds to get “adj” or 6 seconds for “full”. You have to be in full

 

[Lostagain]

Love the Opmid but have been having problems programing it. Got MPH according to iphone gps but cant get far enough in the programing to get Temp to F and tire sprockets Etc.

I tried using the Opmid right out of the box but finally gave in to actually programming it. Turns out it's pretty simple if you just take your time scrolling through the options. Mine came with a multi sheet setup guide in English and Japanese. You get into the full adj mode by pressing and holding A & B for 6 seconds, release when "FULL" is displayed. Then you can scroll through the various sections...A changes the sections, B selects...then A or C increases of decreases as desired. Didn't your Opmid come with these directions?

 

[South of the border]

Opmid doesn't have the Dr. Speed ready until march for the CT125 and they aren't even sure if they'll ship it to the USA. I'm in touch with them almost daily. HardRacing.com doesn't have one to fit it either, but I'm working with them to try to get one. I sent them our wiring diagram today. My ABS fault light (and results in disabling the ABS) comes on in 5-10 miles of highway riding with a 13t front sprocket. Makes no difference if you change the rear Sprocket, if you are running the same gear ratio (3.00) you should get an error. Several people have reported it.

Hi Spydie, are you saying that you can change the rear sprocket and no ABS light issue will arise? Only if the front one is changed will it affect the abs light? I would like to gear mine down a little but don’t want the abs issue. Appreciate your clarification on this.

 

[Spydie]

Hi Spydie, are you saying that you can change the rear sprocket and no ABS light issue will arise? Only if the front one is changed will it affect the abs light? I would like to gear mine down a little but don’t want the abs issue. Appreciate your clarification on this.

No, that's not what I meant. It depends on how much the gear changes. One tooth in the front equals 3 in the rear. So if you change one tooth in the front, it upsets the sensor for ABS. Or, if you change 3 teeth in the rear it does also. But if you change 2 teeth in the rear (41t) then the sensor does not detect the difference. Two of us with 41t rear have reported on that.