This is a belated reply to a query by Kiwi John about a year ago. He noted that his kickstarter slipped a cog if he tried to use it over the full stroke, but engaged properly over a half stroke. I had the same problem with my bike, a Mk V. When I got the bike it did not have the problem. A previous owner had made up an external stop for the kickstart return, so that the internal stop did not come into play. (This is a clue.) Just this week I finally took the mechanism apart to try a remedy. (The answer to John's question whether the mechanism can be dismantled without removing the unit from the frame is Yes, just follow the manual.) I didn't see any noticeable wear or breakage in the ratchet teeth, so I was resolved to just machine a spacer that would bring the ratchet nearer to engagement, so that after the slippage occurred there would be more of the stroke remaining. Fortunately I noticed before I put things back together that the pawl was slightly loose on the worm sleeve for the ratchet pinion. It could be slid about .050" from its "home " position on the worm sleeve. Seeing this enabled me to conceive a plausible explanation for the problem. When the kickstart lever was returned to its home position the pawl hit the stop and the ratchet pinion was driven forcefully against the pawl, thus moving the pawl away from its home position on the worm sleeve. When the kickstart lever was next depressed the ratchet pinion would move easily along the worm into engagement with the ratchet teeth on the bevel pinion. When the ratchets first came into engagement the resistance would cause the ratchet pinion to push against the worm sleeve and move it back into the home position within the pawl. This withdrawal momentarily removed the pressure forcing the ratchets into engagement, and the first tooth was skipped. After the sleeve had been forced back into its proper position in the pawl, the ratchets engaged as they were designed to do. So I reasoned. It seemed to me as if the only way to confirm my theory was to fix the pawl in place on the worm sleeve and try the thing. Upsetting the pawl with a center punch around the perimeter of the serrated portion of the sleeve seemed a possibility, but I elected to silver solder the joint. This I did, and reassembled the device. It worked, and I can now spin the engine with a full stroke. I did also use the .050" spacer that I had made. It fits onto the worm to prevent the ratchet pinion from returning all the way to the pawl. Its outside diameter is 1 3/16", to prevent any possible interference with the kickstarter pinion. The only benefit to this is the quicker engagement of the ratchet.
I would be very pleased to hear of any other members' experience with this sort of problem.
Don Moor