DCT gone badly wrong!

[nigelspencer 15]

So riding in this morning I'm about 2 miles from dropping on to the motorway when the bikes starts to struggle and not hold speed. Thinking it's a results of the hill or headwind I twist the throttle a bit more yet it gets worse, shifts down from 6th to 5th then *BAM* the bike shifts 5th to 2nd (I'm doing about 45-50) the engine screams and the '-' appears in the gear indicator. Get the bike to the side of the road and it's firmly stuck in 2nd but with the clutch disengaged so I can move it - the chain has stretched a lot. Even if it came back to neutral there was no way I was going to ride it having had that happen so the AA come and take it off to the dealer.

 

Anyone had this happen?

[Rocker66 34,351]

Not good. Glad it didn't happen on the motorway. Let's hope it turns out to be something simple and the dealer can fix it quickly. Is it still under warranty?

[nigelspencer 15]

Sadly long out of warranty, 4 years old in June and 36k miles

[Mikdent 4,070]

Holy moly! 

 

I've never heard of this happening before and to be quite frank it sounds a bit drastic, and scary, didn't the rear wheel lock up at all when it dropped from 5th to 2nd?

 

And why on earth would a DCT do that? it's obviously more than a coincidence that it happened just after losing power, baffling. 

 

Have you had the bike from new? If not, was it well looked after by the previous owner? 

 

Sorry for all the questions Nigel, and I hope my post doesn't come across as scare mongering, besides, it's a bike and can always be fixed, at least you didn't come to harm, but I'm curious as to the cause. 

 

Heres hoping that your dealer tells you it's not too much of a fix, keep us posted.  

 

 

 

 

[Andy m 23,427]

Bad luck, hope you get it sorted.

 

Are 2nd and 5th (or maybe 4th) on the one shaft? Sounds like it engaged the wrong clutch on either the last change or the one it was trying to do?

 

Andy

[Rednc750se 171]

Sorry to hear that this has happened, it must be the first time something like this has happened. Please keep forum updated.

[nigelspencer 15]

When it happened it slowed *very* quickly hence I'm glad I wasn't motorway speed (or there abouts ). It stayed in second so I limped to the side of the road, very lucky there was no-one behind me. I'd been suffering from the '-' appearing from cold and it'd been in a few times to try and find out why but it couldn't be identified plus never showed any error info. 

 

I've had the bike from new, always serviced on time

 

Will report back

[MikeBike 5,004]

38 minutes ago, nigelspencer said:

 I'd been suffering from the '-' appearing from cold and it'd been in a few times to try and find out why but it couldn't be identified plus never showed any error info. 

 

I've had the bike from new, always serviced on time

 

Will report back

I wonder if it's connected to the DCT paddles not working that you experienced before as the error code from that should have displayed '-' according to the last post of the other thread and both related loosely to DCT gear changes. Did you get that sorted in the meantime?

 

Edited February 8, 2017 by MikeBike

[embee 7,288]

I wonder if it's anything to do with that selector drum pivot stud thing which has been reported a couple of times? Item 6 below from https://www.bike-parts-honda.com/pieces-honda-detail-71380-71380-NC700XDE-2014-E_17_1-NC+700+X+DCT.html

Can't really think why it would slow beforehand though, was it losing power or something getting tight?

 

Will be intrigued to hear what this is about, like Mikdent says, not heard of this before.

 

[embee 7,288]

Actually thinking about it, I don't believe it can physically go from 5th to 2nd in one go, just like you can't do it on a manual bike, it has to go through the sequence of gears because the shifter only moves the selector shaft 21 (above) one gear at a time before returning to centre, just like a foot-pedal does. Similarly I don't think it will shift down more than one gear without engaging the clutch for it, at least I can't recall ever getting it to do that when pressing the "-" button repeatedly, I'm sure it selects each gear then goes to the next one (I think .....)

Definitely something very odd happened there.

[Mike5100 2,061]

16 hours ago, nigelspencer said:

So riding in this morning I'm about 2 miles from dropping on to the motorway when the bikes starts to struggle and not hold speed. Thinking it's a results of the hill or headwind I twist the throttle a bit more yet it gets worse, shifts down from 6th to 5th then *BAM* the bike shifts 5th to 2nd (I'm doing about 45-50) the engine screams and the '-' appears in the gear indicator. Get the bike to the side of the road and it's firmly stuck in 2nd but with the clutch disengaged so I can move it - the chain has stretched a lot. Even if it came back to neutral there was no way I was going to ride it having had that happen so the AA come and take it off to the dealer.

 

Anyone had this happen?

Is there a clue in the highlighted bit above.  I'm not sure that one catastrophic failure could cause an instant stretching of the chain, but if the chain had previously 'stretched a lot' could it have jumped or in some other way caused the reduced power/drive, then confused the DCT box?

Mike

 

[Guest Hati]

10 hours ago, embee said:

Similarly I don't think it will shift down more than one gear without engaging the clutch for it, at least I can't recall ever getting it to do that when pressing the "-" button repeatedly, I'm sure it selects each gear then goes to the next one (I think .....)

 

I can confirm that. Repeated taps of the "-" button will be ignored by the DCT box and it will just continue its business as usual.

[steve916s 11]

Loose battery connection?

[nelmo 563]

Is this even mechanical? All these issues where 'something' happens randomly smacks of software problems rather than mechanical IMO. And maybe caused by a sensor reading something wrong (because of a temporary bit of dirt/grit?) and sending a signal to the ECU which decides it needs to do something. Once the sensor gets working properly, the 'problem' goes away.

 

Just a thought...

[kayz1 2,928]

I like Mike think it has some thing to do with the chain, has it come off and gone in-between crankcase and sprocket and the one side of the sprocket continued to drive the rear wheel but under reduced torq, hence the need to change done a gear or two but still not enough drive. Just a thought, did you check?

Lyn.

[Mike5100 2,061]

43 minutes ago, kayz1 said:

I like Mike think it has some thing to do with the chain, has it come off and gone in-between crankcase and sprocket and the one side of the sprocket continued to drive the rear wheel but under reduced torq, hence the need to change done a gear or two but still not enough drive. Just a thought, did you check?

Lyn.

wow - yes that would certainly do it wouldn't it.  Mind you the chain would be horrifically slack and I don't think the OP could mistake that for chain stretch could he?

Mike

[Steve Blackdog 687]

Please keep us updated with your troubleshooting. Glad you were able to keep the bike under control. 

[bazza 3,629]

Forget the dct - the loss of power- could be due to something simple like a fuel blockage -that clears and then the gearbox -which has shifted-suddenly gets a lot of revs to deal with?

My KTM 950 was one of the first into Uk and i had fun when the front carb froze up -making it a single approaching roundabouts - then as i exited it came back onto 2 pots! they fixed it  up by fitting pre heaters .But a loss of power, then it suddenly coming back in makes for interesting control!

do keep us informed as i ride a DCT.......

Edited February 9, 2017 by bazza
spelling!

[embee 7,288]

I'm beginning to wonder if it is, as others say, down to the chain coming off the gearbox sprocket. A lot of guesswork but if the chain began to tighten/seize (apparent loss of power?) and then suddenly jumped the sprocket (bang?), the engine would rev high (no drive, feels/sounds like it has dropped down several gears), and the DCT system would determine a fault (comparing wheel speed and gearbox speed would say something is wrong, [--] showing in window), at which point it decides to default to a safe mode when the speed drops (hence fixed in second gear when coming to rest?). As said, a lot of guesswork ..................

 

If it turns out to be simply the chain, and no significant damage done to engine cases (there is a chain safety guide round the front sprocket), then maybe you've got away with it.

 

We'll watch with baited breath.

Edited February 9, 2017 by embee

[Tex 36,816]

"We'll watch with baited breath."

 

Indeed we will.

[rmezei 1]

do you have any updates man?

[Guest phantom309]

i had a time when . i'd changed the rear tyre an set the chain correct , so i was supprised that two weeks after while two up engine revved an no drive . pulled over to find the chain so stretched that it had jumped off , so lucky to have the tools i re-attached the chain an re-tightened the chain. but it was knackered . could believe in two weeks it could go that slack as everything was still tight ( my first thoughts)... new chain an no probs after ..?

[MikeBike 5,004]

3 hours ago, phantom309 said:

i had a time when . i'd changed the rear tyre an set the chain correct , so i was supprised that two weeks after while two up engine revved an no drive . pulled over to find the chain so stretched that it had jumped off , so lucky to have the tools i re-attached the chain an re-tightened the chain. but it was knackered . could believe in two weeks it could go that slack as everything was still tight ( my first thoughts)... new chain an no probs after ..?

Do you have any idea what it could have been so soon after refitting the rear wheel? Rear wheel Alignment? Seems strange that after being fine for so long something caused it to go so slack.

[ste7ios 469]

Bad alignment or incorrect chain slack adjustment?

[Guest phantom309]

honest answer is i don't know. maybe something was not quite straight an running it realined it straight.? causing it to jump off...?  i do know the chain was knackered . but as selling it the day after it happened , the shop could buy the new one not me ...