Tweaking the Electrics

[trapezeartist]

I have now been riding an EM for 4 years but there are still things I think could be done better, and I'm wondering if they are possible.

1. I would like to have a little bit of "engine braking" when the throttle is closed. I quite like the idea of the "Finger Throttle" on this page, https://www.electricmotiontech.com/home/em-epure-race/regen-experiments. If I understand correctly, this would be a straight bolt-on if I could get the right finger throttle. It could replace the present PRB-R (2023 bike) and the 0.8 volt would provide the engine braking. Right?
2. I only ever use green and blue maps so I would like to get rid of the red map so that the sequence would be white-green-blue-green-blue-etc. I assume that is not possible as that stuff is presumably locked into the controller. My aim is to easily switch maps part way through a section. I've done it once or twice going from green to blue but I don't like the idea of going the other way as it would require two pushes of the button. There seems to be a danger of a hurried push-push becoming just one push and that might present a little surprise when going back on the throttle. The purpose is to get the punch of the blue map for climbs and banks but the sensitivity of green for tight turns. I'm thinking of a couple of other solutions. One would be to slip the clutch in blue but I haven't touched the clutch in all the time I've had EMs and I was a bit jerky with the clutch way back when I had a petrol bike. The other thought is to have the training button up on the handlebars in the form of push-and-release. So hopefully the detuned blue map would behave like green or perhaps even a little bit milder. I was looking at https://www.electricmotiontech.com/home/em-epure-race/wiring-diagram and it seems to suggest that the training map used the OPTION port on the controller up to 2021 and that then became the PRB from 2022 onwards. However PRB and FRB seem to just deliver variable or fixed voltage to the same port yet FRB was available on 2021 so how did they get training map and FRB then? Maybe I'm not understanding this right. I've found a blanked-off connector coming out of the controller with green, yellow and black wires. What does that do?
3. I've just removed the lighting circuit from my bike in order to simplify the wiring a bit. I was also concerned that the 12v DC/DC converter was wired direct to the main battery without a fuse, though I've found a fuse on my 2023 that wasn't there on the 2021. No matter, I had already removed the front light so it makes sense to get rid of the back as well and simplify things a bit. Just out of interest, there was another blanked-off connector on the lighting harness with yellow and black wires, labelled S?BD (It's hard to read but I think that's it). Anyone know what that might do?

Edited April 17 by trapezeartist

[ChrisCH]

Will the new up/down map switch fit your model?  I thought they were on the later bikes.  The factor-e will move maps up or down on the fly.  Its one of the things I think make it better than an ICE bike.  I seem to remember the same switch configuration being on the other bikes but our old bike ('21) had the push button set up which scrolls sequentially through as you describe.

[ChrisCH]

Check with them but I think this is the one that will retro fit the earlier bikes.

https://inchperfecttrials.co.uk/products/2024-em-main-command-switch-map-button-fits-models-race

[trapezeartist]

That would be just the job, if it will work with a '23. I think there is a good chance as '23 and '24 are broadly the same bike. I'll give Symon a call today. Thanks.

[trapezeartist]

Unfortunately the '24 command switch wouldn't work on my bike. It connects into the display, not straight into the controller, and presumably the display does something with the signal before sending the necessary to the controller. I think I'm back to learning how to slip the clutch smoothly.

[konrad]

My understanding is that EM allows 2023 models to be upgraded to 2024 specs which would also give you EM Connect.  But you must buy a lot of hardware: TCU, display, switchgear.  Probably more cost-effective just to trade up to a newer bike.

Regarding the school mode on later models.  I have the idea there may be two different places to plug the throttle into the wiring harness -- one for standard mode and one for school mode.  But that is speculation because I don't have a bike to examine.

Regardless, it would be possible to make the throttle less responsive by inserting a resistor in series with the 5-volt reference to the throttle. (In fact, that's how EM implemented the different power modes on their original 5.7.)

For example, let's say the controller expects to see a command signal of 4.8 volts as WOT.  When the controller sees a throttle signal of 2.4 volts, it will produce one-half of its maximum torque (for that map).  If instead, you make WOT produce only 2.4 volts, the torque at any throttle opening will be correspondingly reduced.  Research the theory of voltage dividers to understand this.

Edited April 17 by konrad
typos

[trapezeartist]

3 hours ago, konrad said:

My understanding is that EM allows 2023 models to be upgraded to 20224 specs which would also give you EM Connect.  But you must buy a lot of hardware: TCU, display, switchgear.  Probably more cost-effective just to trade up to a newer bike.

EM Connect can be retrofitted to a 2023, but without the new display. However it is pretty uneconomic: £500 plus sending the bike back to Inch Perfect which is at the other end of the country. So that option is out.

3 hours ago, konrad said:

Regarding the school mode on later models.  I have the idea there may be two different places to plug the throttle into the wiring harness -- one for standard mode and one for school mode.  But the latter is speculation because I don't have a bike to examine.

I can only find one OPTION connector, which is being used for TKO. Inch Perfect confirmed that.

3 hours ago, konrad said:

Regardless, it would be possible to make the throttle less responsive by inserting a resistor in series with the 5-volt reference to the throttle. (In fact, that's how EM implemented the different power modes on their original 5.7.)

For example, let's say the controller expects to see a command signal of 4.8 volts as WOT.  When the controller sees a throttle signal of 2.4 volts, it will produce one-half of its maximum torque.  If instead, you make WOT produce only 2.4 volts, the torque at any throttle opening will be correspondingly reduced. Research the theory of voltage dividers to understand this.

My understanding of electrickery stops at Ohm's Law. I did read up on voltage dividers and it pretty much puddled my brain when it came to devising a practical application. If I tried to do this I think it would probably go horribly wrong. It would also need a A/B handlebar switch to swap between normal maps and soft maps but I can't find such a thing. They are all on/off or horn-type buttons.

Meanwhile your Regen Experiments page (https://www.electricmotiontech.com/home/em-epure-race/regen-experiments) has given me an idea for getting a bit of throttle-off engine braking. I'm going to be offline for a few days but will return to the subject and may try to consult you again on that.

[konrad]

On 4/16/2025 at 11:13 AM, trapezeartist said:

One would be to slip the clutch in blue but I haven't touched the clutch in all the time I've had EMs and I was a bit jerky with the clutch way back when I had a petrol bike.

Your issues with the clutch may not be completely of your making.  

Clutch fiber plates take some time to break in.  You can speed the process (and give the clutch a longer life) by perfectly aligning the plates: https://www.electricmotiontech.com/home/em-epure-race/mechanicals/clutch#h.twzu1hiimf5e

You could also experiment with different clutch fluids.

Finally, my wife tried one of these levers on her Dragonfly: https://www.splatshop.co.uk/trialsolutions-ergo-lever.html   It worked so well, I bought one for my EM. 

[trapezeartist]

On 4/17/2025 at 8:11 PM, konrad said:

Your issues with the clutch may not be completely of your making.  

Clutch fiber plates take some time to break in.  You can speed the process (and give the clutch a longer life) by perfectly aligning the plates: https://www.electricmotiontech.com/home/em-epure-race/mechanicals/clutch#h.twzu1hiimf5e

You could also experiment with different clutch fluids.

Finally, my wife tried one of these levers on her Dragonfly: https://www.splatshop.co.uk/trialsolutions-ergo-lever.html   It worked so well, I bought one for my EM. 

The jerkiness on the clutch dates back to when I had petrol bikes. I've never used the clutch on my EM. Given the complexity of access to the clutch, I think I'll just go for some extended practice before diving into the alignment.

Those Ergo levers look very interesting. I currently use Apico short levers but could certainly live with something shorter. I might give them a go for both clutch and brake.