DCT problem

[Ylwgtr]

Hi everyone! I have a friends nc700 that has a problem with the dct, what happens is the following:
Start engine select drive (display shows d1) after travelling a few meters the display starts the blinking line thing then when coming to a stop the bike selects 2nd gear...if you take off as per normal from 1st fire up it won’t change gear at all but as I said above when coming to a stop it selects 2nd gear. If I turn the ignition off then on again the display reads 2nd gear and it changes itself back to neutral.
If I don’t attempt to ride I can shift from 1st to neutral as many times as I like. I’ve checked the shifter Star/detent wheel and the mechanisms on both sides of the engine and all seems fine, whilst I had it apart I manually selected all gears and no problem with selecting any gears...any idea on where to look next?

 

[Doc True]

The vast majority of DCT issues seem to be solved with a new battery. Try that before anything else.

 

[670cc]

There are people here that have more knowledge of the DCT than I do, but I’ll make a suggestion. Your problem seems to occur only when the motorcycle is moving. The DCT needs to know how fast the wheels are turning. Have you inspected the front and rear wheel speed sensors? Do you also have an ABS fault warning light?

I seem to recall that the DCT will not shift out of first gear if it does not see proper signal from the wheel speed sensors.

 

[670cc]

Chapter 12 of the service manual details extensive troubleshooting steps. Do you have it? It can be downloaded at no charge. Make sure you have a good battery and clean connections.

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[Deleted member 1183]

Also have a look here......

DCT Clutch Calibration

Then perhaps here........

DCT Issue

I concur with the battery check mentioned in one of the posts above. Mechanically the biggest single problem afaik has been with a small bolt/pin/detente breaking in the gearbox. Some early models were afflicted with this.

 

[Jt105]

The DCT is reported to be sensitive to tire and/or sprocket gearing changes. Any changes from stock tire diameter and sprockets could cause the speed sensors to have a mismatch and cause a DCT shifting problem.

I have a manual transmission NC, so no personal experience on this.

JT

 

[Ylwgtr]

There are people here that have more knowledge of the DCT than I do, but I’ll make a suggestion. Your problem seems to occur only when the motorcycle is moving. The DCT needs to know how fast the wheels are turning. Have you inspected the front and rear wheel speed sensors? Do you also have an ABS fault warning light?

I seem to recall that the DCT will not shift out of first gear if it does not see proper signal from the wheel speed sensors.

Yes this is my thoughts as well! I was thinking of this whilst driving home today,I will have a look at it when I get to work

 

[Ylwgtr]

Also have a look here......

DCT Clutch Calibration

Then perhaps here........

DCT Issue

I concur with the battery check mentioned in one of the posts above. Mechanically the biggest single problem afaik has been with a small bolt/pin/detente breaking in the gearbox. Some early models were afflicted with this.

Yeah I had the mechanicals apart expecting to find something there but no such luck

 

[Ylwgtr]

I’ve also noticed after a bit more ride testing the gear display changes to a line after 8klmph or higher...the abs light goes out a little bit higher

 

[Ylwgtr]

Ok today I had an idea..I thought seeing as though I have an issue at 8klms I’d I’d disconnect the speedo sensor,seeing 3 of them I disconnected one at a time and it was then I worked out the “odd” and “even” gear position sensors...I’d worked out I had a suspect “odd “ sensor by swapping it into the “even” spot..well this time I could ride until it shifted into 2nd then shortly after it faulted and upon coming to a stop I noticed it was in fact gearing down to first...i thought great I’m getting somewhere,so out with the Speedo sensor and swap it into the even hole and the suspected one into the Speedo position (thinking the Speedo won’t work) but that wasn’t the case....anyway I was convinced I had at least one dud sensor so put them back in the original configuration and verified the bike behaviour changing with different faults in different gears ect....I took the sensors out and had a friend test them on a scope and I have one dud sensor (the one I had marked with red paint as my calculated guess as a dud ) and one “iffy”/intermittently functional sensor and one good one...I will replace the 2 and report back the results

 

[1wiseguy2]

I'm thinking my abs light goes out within a couple tire rotations (start to the end of my city driveway). So I think that might be the issue.

Yes, it does and if it is not going out almost immediately upon normal forward rotation before you even reach a whole bike length or two something is wrong.

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[Ylwgtr]

Yes, it does and if it is not going out almost immediately upon normal forward rotation before you even reach a whole bike length or two something is wrong.

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No this isn’t how this one works and the Honda manual states 10klmph (I’m not sure how to upload a photo)

 

[1wiseguy2]

No this isn’t how this one works and the Honda manual states 10klmph (I’m not sure how to upload a photo)

I guess I always get to 6 mph prior to getting to the end of my driveway!!

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[Ylwgtr]

I guess I always get to 6 mph prior to getting to the end of my driveway!!

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Dunno mate have a look at the manual....that’s what it says

 

[HarveyM]

You're right that the owner's manual says ABS doesn't function below 10kph, but the service manual is more informative. It says the ABS control module performs a self-check until the speed reaches 10kph, then the ABS is active until the key is turned off.
Next time I get a chance I'll try a couple low speed runs

 

[telecam]

Your shifting motor may be acting up... Took the dealer 4 month to diagnose this on mine, bike only had 6K miles. You'll find the thread of my DCT nightmare here:
DCT Issue . Have you done a DCT calibration? I'd start with that.

Good luck!

DCT CALIBRATION PROCEDURE:

1. Fully warm the engine to normal operating temperature.

2. Make sure that the stop/run switch is in the 'run' position and then turn on the ignition switch while holding down the 'D' shift switch on the right handlebar. Hold down the 'D' switch until the MIL (engine icon) goes off. You should see the outline of the the gear selector box on the LCD display but it should be empty (no D or S, no gear shown).

3. Operate the shift selector switch as follows (one push for each): D-D-N-D-N . After this is done 'D' and 'S' should show in the gear indicator box, along with a '-' sign in the center flashing at approx. 2 second intervals. (If you see an 'L' in the display the engine is not warm enough, if so then shut off the ignition, start the bike and bring it up to normal operating temperature, shut it off, and start again at Step 2.)

4. Start the engine and let it idle. Do not touch the throttle. The calibration is complete when the D and S indicators disappear. Shut off the engine and the calibration process is complete. (If the '-' starts blinking rapidly at 1/2 second intervals then the calibration process failed, shut of the ignition and repeat from Step 2.)

 

[Ylwgtr]

Hi telecam i had read your posts, I’ve put the sensors on a scope and they are dodgy....some of them work until you send vibrations through them from tapping then the signal is intermittent....the sensors were on back order and will arrive this week.....I’m 100% sure this is the problem but will report back

 

[Deleted member 1183]

Just on the recalibration I have noticed that the procedure can vary slightly on different model years at least. My 2017 750 has a slightly different procedure to previous years.

 

[Ylwgtr]

Hello again, just a follow up,the new sensors fixed it

 

[670cc]

Hello again, just a follow up,the new sensors fixed it

Thanks for the follow up. Exactly which sensors were replaced?