The "ESC edition" has a cutout for the primary gear.
4-plate Honda derivate clutch for smallframes
Depending on engine and side shaft tolerance no or up to 2mm spacer is needed. A 1mm spacer comes with the kit, with that the brake back plate can be adjusted to fit directly.
More and thicker ears of the plates and thicker plates themselves allow for longer lifetime of the plates and bell. Higher thermal resilience through higher and better oil flow rate.
Requires less travel to release fully so clutch drag is a thing of the past.
By using motorbike clutch plates the Hartz clutch is superior to all other smallframe clutch systems available on the market. Since the Vespas have been designed for a 3-plate clutch only relatively short clutch travel is possible due to the leverage of the clutch levers. Installing a 4 or 5-plate clutch with normal cork plates the clutch travel needed to disengage the clutch increases by 33% and 66% respectively. Therefore normal clutch travel is not enough to disengage the clutch completely, clutch drag is the result. The clutch plates of the Hartz clutch are not cork plated but are plated with a composite material which is not as compressible as standard cork. Additionally the clutch plates are thinner and have more oil grooves. All this helps reducing the clutch travel needed to disengage the clutch. Also, the plates are not expanding as much under heat as the cork plates do, which allows for an exact and constant pressure point.
We deliver the clutch with 10 uprated springs, but of course you may only need less. The clutch plates are narrow but have the same outer diameter as the Cosa e.g. and hence a larger mean diameter. This means that one of these plates can transfer more torque than a standard plate.
Contrary to the popular fallacy that more friction surface means higher torque, the crucial factors for torque transfer are the mean diameter and of course the number of plates
This kit provides you with a modern clutch, the likes of which are also found in modern motorcycles. As with motorbikes you can shift into first gear, keep the clutch pulled in and push the bike backwards while revving up, no clutch drag whatsoever. At the same time the clutch is still easy to pull and hence makes stop&go traffic go easy on your underarm muscles.
Clutch has been tested by several ESC and DBM riders with up to 35 hp.
Version 4.1: primary gear can be changed without extracting the outer basket
Version 4.2: Vespa flywheel puller is used for extracting, primary gear cannot be changed
Version 4.3 LTH mod.: no judder at full throttle starts