Ducati Monster Forum

Rode the 696 to a friends, parked it in his driveway. Come out to leave a few hours later and try to spin the throttle.

It is completely seized.

The throttle cable if fine, checked it on the bars and followed it to the throttle cam and it works fine, tugging on the cam as I roll the throttle.

However the throttle cam will not move, no flex, no movement, nothing. It is completely locked in position.

Either the cam is stuck or the butterfly in the throttle body is stuck.

Can't start the bike because the throttle is stuck in the closed position and my bike stalls from cold start without a little throttle.

I considered something being stuck in the throttle body, but that makes no sense because I rode the bike up and parked it. If it was a bug there would be some flex, a little movement, but there is zero movement. Maybe a rock? But how would that get in the bike after I parked it.

I'm guessing it is something more mechanical and not due to external variables.

Any ideas or experience with this issue?

Can you pull the filter and look in there?

I could. Remove everything and pull the airbox off and check the butterfly.

Makes no sense though. Even if a small rock got in there the butterfly rotates in a way that would just drop it into the cylinder, I can't see how it would completely seize up. 

Thinking the problem is the throttle cam? I'm afraid to force it for fear of damaging it or bending/breaking the cam.

I agree it makes no sense.

You have to start somewhere.

check both the outer throttle cam assembly and cable AND the inner one betweent the throttle bodies.

my inner one siezed up.. OPEN.. that was fun... WD40 freed it

In the process of removing everything and getting to the TB, on the fuel tank now.

I'm hoping it's something simple I can solve here, not a damaged part.

Just make sure you have it completely freed up.

You don't want it sticking again...open.

I had a throttle stick open.

Fun is an accurate description. ;)

Could it be stuck in the bar end?

I had similar thing happen when the TBs were ridiculously out of sync. I had absent mindedly neglected to screw the air bleeds all the way in before beginning the sync procedure and got a false reading causing me to adjust the TB sync screw to out-o-whack. The throttle butterfly plates were binding inside the bore of the TBs. I freaked before I finally figured it out.

Not at all saying this is what your problem is, this is just for your info.

Have everything stripped down.

TB's are completely clean. Can't rotate ANY part of the TB linkage on either TB.

Problem is the linkage, not the TB itself or the butterflies.

Going to keep "problem solving," aka messing with shit.

Got it fixed and completely back together. About to ride home.

The butterfly for the horizontal cylinder was stuck due to a major buildup of "gunk."
Sprayed some carb cleaner in both throttle bodies, let it soak for a minute and used the wooden handle of a paintbrush (homage to DP) to lightly smack the butterfly. It popped right open and the throttle actuated just fine from there.

Used carb cleaner and an old toothbrush to scrub the TB's and wiped them out with a clean cloth. I'm amazed at the amount of dirt that was in there.

I don't think it was carbon, no combustion in the throttle bodies.. Looked like it was just 5,000 miles of crud buildup.

Not bad tearing the bike down fixing it and reassembling in 3 hours + 1 minute.

Sweet...

I wonder why there's so much crud. I've never really shot carb cleaner into my TBs and they are pretty good at 33,000 miles. I do use BG-44 or SeaFoam with decent regularity. But still so much gunk that it binds the TBs makes me wonder a bit

I agree. It's very strange. When I installed my MWR filter a few weeks ago the stock paper one was fairly clean at 5k miles. The fine foam combined with the oil of the MWR filter should keep out any particles large enough to build up on the TB walls. Buildup like I saw could only be from airborne dirt.

Interesting changes to the bike after cleaning.

1. At startup, no more stalling, no fast idle needed. Bike starts and runs first try. 
2. Bike idles 200rpm higher at idle both cold and hot.
3. Throttle response is MUCH more strong. The TB' went from being thick with black shit to shiny clean.

I can't believe how different the bike is from this little cleaning. I'm wondering if I should run SeaFoam through the entire engine. Put some in the oil/intake/gas tank, and see what happens. I'm pretty sure you can put that shit anywhere.

I'd do the hot water spray and Techron instead of the Seafoam ingestion.  Techron is claimed to be better than Seafoam cleaning the fuel system.  Steam is probably faster cleaning the carbon in the chamber.

I wonder if you are seeing some exhaust pressure wave hitting the cylinders when both valves are overlapped open.  Could account for the crud. 

I wonder if my specific exhaust could be contributing to this problem. However my setup has very low back pressure which is anything would cause the opposite. Drawing out of the cylinder during overlap which explains the backfiring due to unburned fuel being sucked out of the cylinder.

Unless I'm misunderstanding.

Could you have put too much oil on the MWR filter when you installed it?

Hard to say, V-F.   It is not just a matter of back pressure, it involves sound wave resonances and echoes generated where the pipe cross section changes, and it changes over the rev range.  Wouldn't it be great to stick a camera in there and see how this all works?   

I'm glad you are good to go  [thumbsup] 

Came pre-oiled. Didn't seems like an excessive amount of oil. If that was the case, time would be the cure.


That would be very cool. Hopefully my setup if not negatively affecting my bike that much. I'm actually installing a set of baffles this weekend to get me within the dB limits for track use and increase backpressure.

The routing is the same to the mid-pipe. The mid-pipe itself is very very similar to stock as well. Very slight changes overall. Then again, it only takes a little to affect the flow.

Some one pood in it when uwas inside..   [evil]

I would say that the filter was wayyyyyy over oiled. Dust/dirt entering into the filter and then excess oil coming off the filter probably just built up all that gunk...  I would clean/lightly oil that filter...  But luckily it got fixed! Maybe run some fuel system cleaner to get out any more gunk that might have made it past throttle bodies into the engine.

I know seafoam was always talked about very highly in my car wrenching days... I don't know about motorcycles though

At Desert Desmo we typically clean the throttle body bores as part of our 7500 mile maintenance routine because of this very problem.  It is VERY common to see Ducati throttle bodies with lots of gunk around the butterfly valves.  This causes sticking in extreme cases.  However, even absent sticking it often causes poor idle and off idle performance.

We recommend that owners add this quick bit of maintenance to their schedules whenever we meet someone who wants to do his own work.  If you've already go the airbox top off to maintain the air filter, what does it cost you besides a little cleaner and a few Q-Tips?   [thumbsup]

Seafoam is great for gum deposits in the carbs.  Techron is great for carbon.

Except on the 696, you must completely remove the fuel tank, disconnect ecu, coils, battery, entire airbox, and tons of small shit to get the TB's exposed enough to clean them. Not hard, just time consuming.

Hell, a few more bolts and disconnections and I could have pulled the entire motor.

Give me a few key hex keys and some crescent wrenches and I can have a Ducati completely in pieces in about 2 hours.

Putting it back together, well that's a whole different story.  [laugh]