NC750X DCT buggy build

[smrco]

Hello to all of you NC fans!

I am new to this forum. My name is Sebastijan and I come from Slovenia (EU).

I starter this project of swaping a PGO Bugrider 250cc buggy with a 2018 NC750X DCT engine. I just think this is a perfect engine for such a project. But it is not easy to make it work with this DCT transmission, ABS and so on.

So... I have a few questions...

First one is:
Is it possible to make this engine work without the ABS unit? I know it depends on ABS sensors to work with the transmission, but I see there is a Dyno Tool that you connect to DIAG connector and lets you go throo gears with only rear tire spinning. So this is half of the solution...but... Is it possible to only use speed sensor from the output shaft? In theory this one spins synchronised with rear abs sensor, so I don't se the point of having both.

Next question: HISS. Is there a way to disable it?

Third question: Do I need original instruments/dash or will this engine work without it? (with aftermasket unit)

Thank you so much for your answers!

Best regards!

 

[mzflorida]

I have no answers for you but that is super cool! Slovenia is on my list of places to visit.

 

[smrco]

I have no answers for you but that is super cool! Slovenia is on my list of places to visit.

Thank you!
Do it! You won't regret it. I live here and I am still amazed every single day I just love this country.

 

[lootzyan]

... I have a few questions...

The main thing you need is the service manual for this NC750 model. There won't be direct answers to your questions, but it will indirectly allow you to conclude how the system works. Especially the list of DTC code definitions will allow you to conclude what may not work if the system (PCM) does not receive the expected information.
E.g. depending on the version, there is two-way serial communication between the PCM and the combination meter (instruments/dash) so I would think that the original combination meter would be required.

 

[smrco]

Thank you for you reply. I have this service manual and I went through all of it, but like you said, no direct answers. This is why I asked here, maybe somebody allready went through this.

 

[lootzyan]

... This is why I asked here, maybe somebody allready went through this.

That's why I'm telling you. Here you can get suggestions based on information from the service manual. So look for answers in SM anyway.
Another example from SM:
ABS system DTC 7-1 will tell you how important tire size is.
DTC 1-3, 1-4, 1-5 says that improper sensor operation will stop ABS operation,
E.T.C.

 

[dduelin]

The proprietary Honda diagnostic software must be connected to the motorcycle's transmission control module (PCM) to enter the mode that allows DCT operation without synchronized wheel speeds between front and rear wheels. Only dealers supposedly have access to the software.

As you know, there are three sensors recording vehicle road speed and rotational velocity of the two gear shafts in the transmission. If any one of them do not agree with PCM programming the transmission will not shift out of first gear.

 

[smrco]

That's why I'm telling you. Here you can get suggestions based on information from the service manual. So look for answers in SM anyway.
Another example from SM:
ABS system DTC 7-1 will tell you how important tire size is.
DTC 1-3, 1-4, 1-5 says that improper sensor operation will stop ABS operation,
E.T.C.

View attachment 53541

Thank you for this. I am looking into it.

 

[smrco]

The proprietary Honda diagnostic software must be connected to the motorcycle's transmission control module (PCM) to enter the mode that allows DCT operation without synchronized wheel speeds between front and rear wheels. Only dealers supposedly have access to the software.

As you know, there are three sensors recording vehicle road speed and rotational velocity of the two gear shafts in the transmission. If any one of them do not agree with PCM programming the transmission will not shift out of first gear.

I read this in the manual yes. I have to find out somehow if this "service mode" will stay permanently activated once they set it, or will it reset to normal mode again after disconnecting diagnostic software or restarting the bike. And if it allows you to go through the gears with the rear wheel still (let's say without the chain mounted) If this would be possible, that this is a solution for me. Maybe I need to go to a dealer that is willing to take the time and try it out for me.

 

[dduelin]

I read this in the manual yes. I have to find out somehow if this "service mode" will stay permanently activated once they set it, or will it reset to normal mode again after disconnecting diagnostic software or restarting the bike. And if it allows you to go through the gears with the rear wheel still (let's say without the chain mounted) If this would be possible, that this is a solution for me. Maybe I need to go to a dealer that is willing to take the time and try it out for me.

Diagnostic mode only works with the Honda software when plugged into the bike's onboard connection. Unplug it and it no longer defeats the DCT self-protection mode.

I worked for a Honda dealer.

 

[smrco]

The proprietary Honda diagnostic software must be connected to the motorcycle's transmission control module (PCM) to enter the mode that allows DCT operation without synchronized wheel speeds between front and rear wheels. Only dealers supposedly have access to the software.

As you know, there are three sensors recording vehicle road speed and rotational velocity of the two gear shafts in the transmission. If any one of them do not agree with PCM programming the transmission will not shift out of first gear.

I read this in the manual yes. I have to find out somehow if this "service mode" will stay permanently activated once they set it, or will it reset to normal mode again after disconnecting diagnostic software or restarting the bike. And if it allows you to go through the gears with the rear wheel still (let's say without the chain mounted) If this would be possible, that this is a solution for me. Maybe I need to go to a dealer that is willing to take time and try it out for me.

Diagnostic mode only works with the Honda software when plugged into the bike's onboard connection. Unplug it and it no longer defeats the DCT self-protection mode.

I worked for a Honda dealer.

Ohh this is great info! Thank you for that.

Ok, so on to the next solution.
I have two more options...

First is to make a (arduino?) logic that inputs signal from output shaft and changes it so a signal that would normaly be on front and rear wheel.
So, I know that...

Output shaft has 30 pulses/rev
Front wheel has 60 pulses/rev
Rear wheel has 50 pulses/rev

Sprockets are 17 and 39
...so... 17 / 39 = 0.436
Front wheel 60 x 0.436 = 26.15 (26 pusles) pulses/rev
Rear wheel 50 x 0.436 = 21.79 pulses/rev (22 pulses)

Second option is to make a "metal ABS ring" with 26 and 22 marks to put it on a front sprocket and put ABS sensors there...

 

[smrco]

One more question. Does anybody have 2018 DCT wiring diagram? I have older diagrams but those are a bit different.

 

[Airfiddler]

Interesting project. Too bad you don't have the manual version of the engine, probably would be a lot easier to figure out. Of course the challenge is half the fun.
Hope you can work it out. Keep us updated.

 

[lootzyan]

One more question. Does anybody have 2018 DCT wiring diagram? I have older diagrams but those are a bit different.

I have a newer wiring diagram. It was said that it was from the 2021 model. I cannot confirm if this is correct information. One thing is for sure. There is a significant difference in this version of the diagram from previous versions from before 2015. To find out, you'll probably have to make friends with the technicians at your local Honda dealership.

 

[Zalm]

So, ...
to make a "metal ABS ring"...

Output shaft has 30 pulses/revOutputShaft
Front wheel has 60 pulses/revFWheel
Rear wheel has 50 pulses/revRWheel
Sprockets are 17 / 39 = 0.436

Ok,

But tires 120/60-17 and 160/70-17
Front wheel diam = 432 mm + 2* (120*0.6) = 576 mm
Rear wheel diam = 432 + 2* (160*0.7) = 656 mm
-> Front wheel rev = Rear wheel rev * (656/576)

Rear wheel 50 x 0.436 = 21.79 pulses/revOutputShaft (22 pulses)
Front wheel 60 x 0.436 x (656/576) = 29.79 pulses/revOutputShaft (30 pulses)
...
(Question: Can you add another sprocket -with holes- anywhere on the chain? You would have more room to place the sensors...)

 

[smrco]

Interesting project. Too bad you don't have the manual version of the engine, probably would be a lot easier to figure out. Of course the challenge is half the fun.
Hope you can work it out. Keep us updated.

DCT was the reason I went with this engine. It was this one or Africa Twin...but africa is just too much for this buggy. Maybe next one

 

[smrco]

I have a newer wiring diagram. It was said that it was from the 2021 model. I cannot confirm if this is correct information. One thing is for sure. There is a significant difference in this version of the diagram from previous versions from before 2015. To find out, you'll probably have to make friends with the technicians at your local Honda dealership.

View attachment 53547

Ohhhh thank you sooo much! This is it! The one I need. All the colours match my cables

 

[smrco]

Output shaft has 30 pulses/revOutputShaft
Front wheel has 60 pulses/revFWheel
Rear wheel has 50 pulses/revRWheel
Sprockets are 17 / 39 = 0.436

Ok,

But tires 120/60-17 and 160/70-17
Front wheel diam = 432 mm + 2* (120*0.6) = 576 mm
Rear wheel diam = 432 + 2* (160*0.7) = 656 mm
-> Front wheel rev = Rear wheel rev * (656/576)

Rear wheel 50 x 0.436 = 21.79 pulses/revOutputShaft (22 pulses)
Front wheel 60 x 0.436 x (656/576) = 29.79 pulses/revOutputShaft (30 pulses)
...
(Question: Can you add another sprocket -with holes- anywhere on the chain? You would have more room to place the sensors...)

Actually I think it is easyer for me to make a ring because sprockets are sooo close on my buggy. Diff is much much closer than rear wheel was.

 

[lootzyan]

I see that Honda makes an SXS buggy, a Talon 1000 series with a 999cc engine and DCT. There is something to follow as an example.

 

[smrco]

I see that Honda makes an SXS buggy, a Talon 1000 series with a 999cc engine and DCT. There is something to follow as an example.

View attachment 53551

Yes I know. But for me buggy has to be under 300kg and low on the ground. Like crosskart. Talon is 800kg. So almost a small car. I have Talon service manual but it is totally different from what I am building. But Talon has Africa Twin engine