There is no spag in the 961 engine.
The starter assembly contains a Bendix style clutch/release mechanism to protect the starter. Similar to the design used by Harley according to my mechanic.
When you press the starter button, the Bendix rotates and locks the pinion gear to the starter.
The pinion is then extended into the primary to engage the ring gear attached to the cultch basket.
Then the clutch hub gear rotates the balancer gear, which in turn, rotates the crankshaft.
The design has a couple of failure points.
The Bendix on a starter relies on an internal clutch mechanism that can become over worked with heavy use, and fail. This will result in the starter spinning up quickly, and not engaging the pinion gear. This has happened to my 961, recently.
The pinion gear is often slammed into the ring gear on startup. The pinion may have to rotate several times after contact with the ring gear before the two mesh properly. Obviously this is less than optimal for long term reliability, and can produce audible and unpleasant noises.
Finally, from postings on the UK NOC site there are some reports that the early 961’s may have ring gears with teeth that have the wrong pitch to mesh with the pinions. The effect can be grinding/grating noises coming from the primary on startup.
A more modern pre-engagement starter design with a spag would certainly be better, but the 961 starter design is what it is, and we have to live with it unless the factory is willing to redesign the thing.