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Throttle slack fix - Multistrada 1200DVT

2366 Views 6 Replies 4 Participants Last post by  stomp944
I find the slack in the RBW throttle of the 1200DVT model Multis to be unacceptably wide and to interfere with quick, smooth downshifts. No aftermarket solution exists for this model (MY '15-'17, I believe). The RBW assembly is different from the 1260 and from other Ducati models with RBW, so the solution is unique to the 1200DVT. In the later DVT, Panigale and Monster RBW, the aftermarket red plastic spacer takes the loose space up and eliminates the slack. The 1200DVT assembly is different, but this fix is similar, and doable to tame the 1200DVT sloppy throttle. It can be done in 10-15 minutes unless you allow the throttle spring to pop out and unwind (and then it's anywhere from 3 hours to never).

The RBW assembly employs a wedge shaped nub on the throttle tube resting in a wedge shaped space in the assembly collar around the handle bar. The space of the slot on the RBW assembly collar is 7mm, while the nub on the tube is 6mm, leaving 1mm of free play in the assembly, translating as a loose throttle and delayed engagement. The circumference of the throttle tube is roughly 75mm, so quick math finds that 1mm of space of rotation is 1.33% of the diameter of the throttle. Oh, not too much you say? It translates to almost 5 degrees. And it doesn't account for the effective functional rotation of the throttle from zero to max, which is not anywhere near the full circumference, but only 20% of the circumference of the tube - so the measured slack of 1mm accounts for 6.667% of available activation, more than half of a 'blip' necessary for smooth, quick downshifts. This accounts for a lot of delay in triggering RBW signals and a lot of room for misapplication. But also, the further away from the center of the bar, the longer the circumference of the circle (ie where your wrist is located inches from this point), the more rotational distance must be covered and the more this dead rotation space is magnified. I measured roughly 80mm from the center of the grip to my wrist and calculated a circle circumference here of just over 500mm. Thus the tiny 1.33% (5 degrees) rotation space at the throttle translates to almost 7mm of travel at your wrist before anything happens. I can see my wrist move up and down over this arc without beginning to activate the RBW mechanism. It's a significant amount, especially where precision and timing in throttle operation is required.

You'll need a #25 Torx security bit (available at Harbor Freight and other hardware stores - the kind with the hole in the middle) to remove the cover. I bought a kit with a couple dozen sizes for under $7. STOP - before proceeding you must be aware that the throttle return spring is under tension and is held in place by the aft portion of the clamshell cover that clamps the throttle mechanism. These steps are easily doable by only removing the front half - hold the aft half in place against the bar and the spring will not slip out. If it does, it's a nightmare to get slotted back in under tension. Rear half still against bar in photo below.

Undo the hex bolt (5mm) on the bar end (only just until barely loose, so 'eccentric' nut does not stay inside bar), and gently take the bar end off the bar. Take the forward side of the throttle cover off (2x #25 Torx). You can rotate the right side mirror inward to clear some working space (remember, the mirror bolt is reverse thread). The nub on the throttle tube and its slot is shown in the photo below.


Slightly separate the black throttle tube from the white collar as in the photo (note, aft side of cover still holding throttle spring under tension here). An old plastic file folder I had lying around is 0.45mm thick. Cutting a tiny piece 6mm wide and folded over created a tiny spacer to slip vertically into the slot along with the throttle tube nub. The nub now sits snugly in the slot and cannot rock back and forth. The throttle tube no longer has a rocking motion on the bar, and the revs pick up the moment the throttle is twisted. No change to idle, or throttle full-stop point. The nub position at rest is a fully closed throttle.


Carefully put the forward cover on and rotate until the pin drops into the hole in the bar and both sides are snug around the bar. Ensure the grip heater wires exit the cover as they did originally, and tighten the two Torx bolts. Gently replace the bar end weight and bolt.

In above photo the plastic is tripled up; I found this too thick to insert, and cut a piece off to just a double fold. A quick ride confirmed a noticeable and substantial change. I find somewhat more hand/wrist rotation than I'd prefer is still required to raise rpm a few thousand, but it is many times better than stock, and enough to soon get new muscle memory embedded to enable smooth downshifts. It does not matter whether the spacer is put on one side of the nub or the other (it will still return to zero).

Side note - I tried another method first, which was to attempt to take up slack in the tube/bar space with a thin plastic sheet cut into a strip. It was very difficult to insert, and the throttle tube bound up too much for this to work. Maybe a much thinner piece of plastic might help, however this approach still does not address the root issue of space built into the RBW assembly itself.

Another side note - engine 'high' setting produces a slightly more brisk rise in rpm that is helpful in calibrating blipping technique. I moved my Touring default up to high from medium since the medium engine setting response is noticeably sluggish.
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Nice write-up! Many thanks-
what a nice explanation ! thanks a lot !
I'm an idiot, I need lots of pictures with arrows, numbers and letters.

Better yet, a YouTube video !
Ha. Understood. We can do it in one photo with arrows.

After bar end is removed and front half of cover is removed, this is what you'll see and pretty much all you need.
Blue arrow - the aft half of the cover that must remain in place against the bar to keep the throttle return spring from popping out.
Yellow arrow -the rbw collar, also pointing to the wedge-shaped gap.
Red arrow - nub or tab on throttle that slots into the collar.
Any firm spacer 1mm thick or slightly less (like my folded over plastic file folder piece) will take up the space/slack when slid back into the collar space with the throttle nub.
I did a 200 mile ride yesterday over freeway, city, canyon and desert and this mod works exactly as intended.
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As an aside, the clutch friction zone and engagement point is also an important element to accurate and efficient rev matching. Before the throttle mod here, I didn't give this any initial attention when dialing things in (bike is still new to me). As delivered, my clutch lever was adjusted far away from the grip. On its own, no big deal and easy to to operate, but contributes to harder rev matching on downshifts where speed and timing matter. As with many things in life, little changes can make a surprising difference, especially given that these are very quick yet subtle, and virtually simultaneous movements we are talking about. I experimented a little recently and found by adjusting the lever closer to the bar, the timing to disengage and re-engage the clutch was reduced just a fraction, but there was a noticeable difference. Like your wrist at the throttle, fingers using less clutch lever travel in both directions also helps timing and smoothness in your rev matching technique.


FYI: Push the lever out slightly which frees the threaded adjuster knob. Turn the knob counter-clockwise in quarter turn increments to move the lever closer to the grip; clockwise moves the lever away from the grip.
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