UPDATE: Still Stuck Throttle

7725 Views 23 Replies 11 Participants Last post by littleowl, Nov 15, 2015

kernelPanicked

Discussion Starter · Nov 2, 2015

First ride on my new FT today. I really enjoy this bike, but as with many shakedown cruises, there was a problem.

After about an hour, the throttle started to stick intermittently. By the time I got home, it was happening constantly.

For example, if I accelerate to 4-5k rpm, and then pull in the clutch, the engine races higher. Riding in gear, the engine just won't engine brake at all. This happens in every RPM range I rode. Basically, the bike will increase throttle but not decrease. A clutch and blip usually clears it.

First time this happened during hard acceleration, it was pretty scary. I'm torn about riding the bike at all as I don't consider it entirely safe. At this point the only place I might ride it is to the dealer. Since I don't have an easy way to tow it...

... Has anyone else experienced a similar problem, and what was the fix? I'd like to do something before attempting the ride to the dealer. Even if it's just cable lube.

1 - 20 of 24 Posts

Slaine

· #2 · Nov 2, 2015

Take it to the dealer, its not normal. You could also check to see if the barend weight is touching against the throttle tube.

John

· #3 · Nov 2, 2015

Mine was sticking a while ago after a service where the bar end weight was tightened up too much against the throttle. When cruising, if i let go of the throttle, the throttle stayed exactly where it was, it didn't close itself as it should do.

If you are closing the throttle but the revs are not dropping, I wouldn't ride it, I would report to the dealer and have them collect it.

mtb2104

· #4 · Nov 2, 2015

+1 for the bar end plug...

stavely

· #5 · Nov 2, 2015

I'd have a quick scan around the bar end mirror and throttle cable routing. If it's not an easy fix I'd ride it to the dealer with my finger hovering on the kill button.

c turner

· #6 · Nov 2, 2015

If you don't feel "safe" riding, call Roadside Assistance and have them collect the bike. Seems a perfect reason to use the service.

Cliff

kernelPanicked

Discussion Starter · #7 · Nov 3, 2015

Update: I called my dealer and they picked the bike up within a couple of hours. That's the good news.

I got a call from their warranty manager today, and he said that he reset the TPS sensor and a few other ECU settings and *then* rode the bike, and was not able to duplicate the problem. I guess riding before fixing it to confirm & experience the issue slipped their minds. Oh well. I asked that they confirm the throttle system is properly lubricated as well, as it feels exactly like the throttle is still open. They said they'd do that, so between that and the electronic resets, it should be sorted out tomorrow.

I hope I don't have any reason to revisit this thread. Thank you for the help, all.

John

· #8 · Nov 3, 2015

Good result, glad you got it sorted!

kernelPanicked

Discussion Starter · #9 · Nov 4, 2015

Update: It is NOT sorted.

Bike was delivered back from the dealer and is still doing it. I managed to get some video since they said they couldn't replicate the problem.

Here are two videos shot while riding. I don't have a good cam for the purpose, this is an improvised cell phone chest mount:
Dropbox - high-throttle-1.m4v
Dropbox - high-throttle-2.m4v

I noticed later, however, that the same thing happens when the bike is standing still and free-revving. So here is clearer video of the same phenomenon.

Cold engine (had been run 1-2m):
Dropbox - cold_rev.m4v

Hot engine (had been run ~30 miles):
Dropbox - hot_rev.m4v

If what is happening in the first and second videos is not clear, watch them after the third and fourth. The engine is doing the same thing. In these videos I am in neutral / holding the clutch, but the bike definitely also pulls in gear.

As you can see, it is not throwing codes, or at least not a CEL.

I sent these videos to the dealer. They're going to collect the bike again tomorrow. Any thoughts? Also, can somebody confirm for me that this is NOT normal for Scramblers to do?

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tonyjuliano

· #10 · Nov 4, 2015

No, not normal - nor widely reported as a fault.

There is probably an air leak in the intake system somewhere.

Sent from my iPhone using Tapatalk

kernelPanicked

Discussion Starter · #11 · Nov 4, 2015

Makes a lot of sense. That would explain why the throttle is probably shutting but the engine keeps running. Still, I'd think the TPS would show idle position and a code would get thrown.

tonyjuliano

· #12 · Nov 5, 2015

kernelPanicked said:
Makes a lot of sense. That would explain why the throttle is probably shutting but the engine keeps running. Still, I'd think the TPS would show idle position and a code would get thrown.

TPS does not come into play during idle.

Sent from my iPad using Tapatalk

Derek

· #13 · Nov 5, 2015

tonyjuliano said:
No, not normal - nor widely reported as a fault.

There is probably an air leak in the intake system somewhere.

Sent from my iPhone using Tapatalk

Or possibly the servo motor for the idle control sticking.

greer

· #14 · Nov 5, 2015

Hope the dealer nails it this time. Good luck, please post back and let us know.

Sarah

kernelPanicked

Discussion Starter · #15 · Nov 5, 2015

How does the ECU know when the throttle is at idle position? Low TPS reading, idle position switch, something else?

I wonder if I can get my hands on a service manual. This is the newest bike I've owned (all my EFI experience is with cars) and I'd like to understand its internals.

Derek

· #16 · Nov 5, 2015

From the TPS reading. As near as you will get to a proper service manual downloadable here DUCATI 2015 Ducati Scrambler 800 Full Manual PDF

kernelPanicked

Discussion Starter · #17 · Nov 5, 2015

Whoa, Derek... that manual is just what I wanted. Weekend reading. Thank you!

tonyjuliano

· #18 · Nov 5, 2015

kernelPanicked said:
How does the ECU know when the throttle is at idle position?

This is a bit of a "misnomer". ECU doesn't get "idle position" from the TPS - it gets "throttle position". If it detects fully closed throttle position, the ECU itself sets idle.

Derek

· #19 · Nov 5, 2015

Yes, that's putting it a bit more clearly than I did.

kernelPanicked

Discussion Starter · #20 · Nov 5, 2015

Dealer has bike. They've seen the video and should be able to reproduce the problem / work on it. I'll update with their resolution.

1 - 20 of 24 Posts

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