Quick Shifter- false neutral when engine braking and fuel sending unit - Ducati Supersport 939 Forum
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post #1 of 99 (permalink) Old 08-06-2018, 11:10 PM Thread Starter
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Quick Shifter- false neutral when engine braking and fuel sending unit

My 2017 Supersport S has almost 7,000 miles. The quick shifter has been acting up. When engine braking, the transmission will shift from second gear to neutral when braking under light load or coasting. It happened a couple of times when I tracked bike at COTA. It is unsettling, because you all of the sudden lose power and engine braking. The transmission shifts into neutral which affects the steering and geometry of suspension.

I first thought maybe I accidentally tapped the shifter. But it has happened multiple times, and this is without any input from tapping the shifter. It appears to happen only in second gear. It occurs only when engine RPMs are less than 3,000 RPM. I don't recall seeing any engine error messages.

Also, my sending unit is failing. Fuel light continues to flash and gas gauge does not work. This happened multiple times on my 2014 MultriStrada. Had to replace twice under warranty. Hopefully, the new part number will last longer now bike is out of warranty. I think the ethanol gas causes this to occur in US.

Has anyone else experienced these problems?
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post #2 of 99 (permalink) Old 08-07-2018, 12:13 AM
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D4mn...it looks like the quick shifter really f#cks up the electronics. Sorry dude, youre not the first one to report issues with DQS. Hopefully some one here points you the right way

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post #3 of 99 (permalink) Old 08-07-2018, 12:43 AM
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I'm not sure I see the connection between the QS and your bike dropping out of 2 into N under engine breaking. All the QS does is blip the throttle or cut the ignition to rev-match between gears. Once you have a gear engaged the QS is literally doing nothing. Have you tried disabling the QS and see if the problem persists?

This sounds to me like you need to have the shifter fork adjusted, or the spring is bent or broken. If it's still under warranty I'd have the shop pull the left cover and inspect for an obvious issue.

The fuel gauge thing sucks.
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post #4 of 99 (permalink) Old 08-07-2018, 02:44 AM
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Isnít this the same as @Rhino original problem?

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post #5 of 99 (permalink) Old 08-07-2018, 04:50 AM
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Ok @ssrealty I unfortunately know more than I care to or thought I ever would about the DQS and if your description is correct it doesn't make sense to me ? as @psyopper has said
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I'm not sure I see the connection between the QS and your bike dropping out of 2 into N under engine breaking. All the QS does is blip the throttle or cut the ignition to rev-match between gears. Once you have a gear engaged the QS is literally doing nothing. Have you tried disabling the QS and see if the problem persists?
his suggestion of possible faulty shifter and broken spring is plausible. Is the bike going into neutral or False Neutral ? if the neutral light comes on then its a physical gear change. I do know that a Faulty DQS can cause some crazy things. Mine went into severe engine braking and instant full throttle without touching the throttle or gear lever. I was going flying over the handlebars till the bike took off and caught me up, quite hairy. anyway at the time I had thought it had dropped gear till I learnt that the DQS interacts with the ECU, throttle sensor, fuel mapping sensor gear select sensor etc and depending on the messages sent can cut 100% fuel causing severe engine breaking. But a physical gear change may be something else. I would get it to the dealer for inspection and in the meantime disable the quick shifter in the menu options. good luck and let us know what happens.
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post #6 of 99 (permalink) Old 08-07-2018, 06:22 PM
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Quote:
Originally Posted by ssrealty View Post
... When engine braking, the transmission will shift from second gear to neutral when braking under light load or coasting. It happened a couple of times when I tracked bike at COTA. It is unsettling, because you all of the sudden lose power and engine braking. The transmission shifts into neutral which affects the steering and geometry of suspension.

I first thought maybe I accidentally tapped the shifter...
Have you adjusted the gear lever? I've set mine so it rests just below my foot when riding. Standard settings were too high, so I either had to have an unnatural bend in my ankle or ride with my ankle cocked so my foot was away from the lever. Even so, a couple of times when I relaxed my ankle I would activate the quick shift. And, because it was unintentional, there wasn't a positive gear change and I often found a false neutral.

You might also consider one of the aftermarket adjustable gear levers, where you can move the shift peg along the lever so it sits in the right spot on your foot. I found the stock position too short for my size twelves, but even my wife (who is far more dainty) agrees the 'extended' position is far better.

(I must get around to posting pictures of that particular mod...)

HTH
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post #7 of 99 (permalink) Old 08-08-2018, 04:44 AM
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Quote:
Originally Posted by theresanothersteve View Post
Have you adjusted the gear lever? I've set mine so it rests just below my foot when riding. Standard settings were too high, so I either had to have an unnatural bend in my ankle or ride with my ankle cocked so my foot was away from the lever.
There were a lot of folks that did this adjustment way back when the bike was new. It seems Ducati shipped the SS just a bit off. I really was meaning to make it myself, but life got in the way late last year and I never got around to it. Now, I've adjusted to it, instead of the other way around, lol. Definitely worth doing, though, for sure.

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post #8 of 99 (permalink) Old 08-08-2018, 06:08 PM
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Quote:
Originally Posted by se7en View Post
There were a lot of folks that did this adjustment way back when the bike was new. It seems Ducati shipped the SS just a bit off. I really was meaning to make it myself, but life got in the way late last year and I never got around to it. Now, I've adjusted to it, instead of the other way around, lol. Definitely worth doing, though, for sure.
First thing I do when I get a new bike home is adjust the pedals and levers (both for alignment with my arm in the riding position and reach).

Now I've learnt with these new fangled bikes to adjust sag and damping as well (adjustments like these were just coming in when I last rode and were, shall we say, crude and ineffective).

Once the bike is better set up to suit my large, fat frame go out and play...
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post #9 of 99 (permalink) Old 08-08-2018, 06:22 PM Thread Starter
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It is definitely not a false neutral issue. I have had many false neutral problems occur on my Ducati's if you don't shift hard enough. Usually the false neutral can be eliminated by just making sure you shift gear with more effort.

This is a different problem, and it occurs with no shift input. The bike by itself just upshifts from second gear to neutral. Ducati Austin sponsors track days at COTA. They did some minor adjustments to shifter at the track, but the problem continues.

The fuel sending unit is on order. I will have dealer check out when I drop off to replace fuel sending unit. My concern is I won't be able to duplicate problem. It does not happen all of the time. It is intermittent.

Last edited by ssrealty; 08-08-2018 at 06:36 PM.
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post #10 of 99 (permalink) Old 08-08-2018, 10:07 PM
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I agree with ssrealty... if you just nudge the shifter and don't make a positive engagement when going down, typically from 3-2 I too have experienced neutral on a few occasions. Certainly gets you attention on the way down the mountain !
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