Minarelli starter gear set (16 mm)

The kickstart mechanism on Minarelli engines (especially the horizontal type used in models such as the Yamaha Aerox, MBK Nitro, Malaguti F12, etc.) is a part that often needs attention. The 16 mm dimension refers to the diameter of the kickstart quadrant (half-moon) shaft, which locates in the variator cover.

What makes up the Minarelli starter gear set?

A standard set usually includes:

1. Kickstart quadrant ("half-moon"): The main toothed part that is turned by the kickstart lever.

2. Kickstart pinion (with spring): A smaller gear that "jumps" forward when you press the kickstart and engages with the teeth on the variator pulley.

3. Return spring: A large spring that makes sure the kickstart lever returns to the top position after starting.

4. Shims and circlips: Important so that the gear has no play (axial wobble).

Important fitting details

• Why the 16 mm shaft matters: Make sure the bushing in your variator cover is exactly 16 mm. If the set doesn't match the shaft diameter, the quadrant will wobble or stick.

• Pinion gear: This is the part that wears most often. If you hear a rattling when kick-starting the scooter or the gear slips (as if it is "clattering" over the other teeth), the gear is worn or the spring can no longer push it out properly.

• Lubrication: This is a critical point. The Minarelli kickstart mechanism works in a "dry" environment (with no direct oil bath), but dust from the belt gets in there. Never lubricate the gears with thick grease (Solidol) – it will attract belt dust and turn into "sandpaper" that eats the teeth within a single season. Use dry-type spray lubricants (e.g. PTFE or silicone) or apply a very thin layer of high-temperature grease.

Checks before replacement

1. Variator pulley: Before replacing the set, be sure to check the teeth on the variator pulley (which turns on the crankshaft). If they are worn to points, a new kickstart pinion will wear out quickly.

2. Bushing in the variator cover: If the 16 mm shaft wobbles in the cover itself, replacing only the gear set may be pointless – the bushing in the cover needs to be replaced or restored.

3. Circlip: When reassembling the mechanism, make sure the circlip is properly seated in its groove. If it pops out while riding, the kickstart quadrant can work its way out and damage the variator or the belt.