Monday, 21 September 2015

How to de-restrict a Ducati 659

Ducati released a LAMS approved Monster for the Australia-NZ market a few years back by making small adjustments to the existing Monster 696. But shorter piston strokes, a lower compression ratio and revised cam timing were insufficient to meet the 150kW per tonne requirement. A restrictor plate has been added to the throttle housing to prevent the 45mm diameter butterfly feeding both cylinders from opening fully. The plate physically blocks the throttle from moving more than 30-40% and while this does not prevent the rider from accessing most of the torque available, there is a significant power increase to be had if this stop is removed. Removing the plate is easy to do and easy to reverse, with no damage and no indication that it has been altered.

The plate, labelled ZDM-R32 and located on the right hand side of the throttle housing, is held in place by means of a long threaded bolt that passes all the way through the housing. This can be unbolted from the left side of the bike using an 8mm socket and ratchet extension.
Once the bolt has been undone you can move the plate to the side and this will immediately de-restrict the throttle. The locking bolt can be kept in place with a new lock nut. Of course, this will affect the fuelling set up of your Monster and you will need to talk to your Ducati mechanic about the best way to handle this.

NOTE that modifying the motorbike in this manner will negate your factory warranty (if your bike is less that 2 years old) and your bike will no longer be LAMS approved. It should only be done after you have passed your restricted examination and you are riding on a full licence. However, it is a simple process to reverse by putting the plate back in the original position.

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