Ducati throttle body sticking
On Wednesday I rode my '04 Ducati Monster S4R to work. On the way home I noticed that the bike was sightly more hesitant to roll off the throttle occasionally. It seemed like there wasn't as much engine braking as normal, but I chalked it up to paranoia on my part.

On Thursday I took the Duc out to one of my favorite twisty roads. Within a few corners I was having some very serious issues: The throttle was sticking open! The first time I attributed my slide to poor road conditions, but after a second lurid ass-end drift I realized that something wasn't right. I clutched the bike down the rest of the hill.

I took a peek at the throttle mechanism (thankfully, on a naked bike, these things are easy to see). Turns out the throttle body simply wasn't closing, and because the throttle on a Ducati is NOT a push-pull system I couldn't manually close the throttle. I lubricated the throttle return springs with some WD-40 but could not get the vanes to return to closed position automatically, so I caught a ride, picked up my truck, and towed the bike back home.

Today I cleaned everything well and lubricated the throttle cable to no effect, and then took apart the airbox system (geez, Ducati engineers, did you have to make it so that I had to remove the radiator and shroud just to get to a bolt to remove the airbox from the frame? seriously?). This is what it looks like, in fiche form:



The throttle shaft running between both throttle bodies is what controls the simultaneous actuation of the butterfly vanes. It's a simple pushrod system. Well, when I disconnect the pushrod from the front throttle drum everything works perfectly. Both throttle vanes open easily and smoothly and snap closed instantly. With the pushrod connected, however, things get strange. The throttle is hard to open and sticks solid, requiring quite a bit of pressure to return it to closed. I lubricated the attachment points but as soon as the shaft is reconnected the throttle system doesn't want to play nicely, yet without the shaft -- which is a simple solid threaded rod -- both throttle systems work beautifully.

I hope that you folks who are snowed in aren't too bitter to help a fellow cyclist. ;) That said, what am I missing? Why is the throttle shaft causing me problems? The problem really came on suddenly, without any apparent cause (no falls or shocks or anything, and the pushrod does not appear to be bent).

Thanks!