Clutch / Gearbox

Removal of the clutch cover reveals a cassette-style gearbox system.  

This has the hallmarks of being an XiU-rdi Engineering design.  Notice the bright blue anodizing along with the stylized “X” and part number in silkscreened white paint.  The fact that the gearbox assembly is held in place using shoulder screws is also telling.  That type of screw was used on the EFI OSSAs, which had a gearbox designed by Josep “Xiu” Serra.  

The clutch itself has 3 friction plates and 10 clutch release arms (also known as fingers).  It is very similar to the GasGas Pro and Mecatecno Dragonfly designs.

The primary drive has 33 teeth on the pinion gear.  A standard clutch basket has 75 teeth, which yields a 2.272:1 ratio.  This makes for a faster-turning clutch basket with lesser torque multiplication than an internal combustion trials bike. 

The secondary drive ratio is 4.1:1  (10-tooth front sprocket, 41-tooth rear sprocket). 

The gearbox shift pattern is the typical 1 down, 3 up with neutral between 1st and 2nd.

Gearbox ratios were estimated from the ground speed achieved in each gear, and other known factors.  

1st gear 3.44:1 (overall ratio: 32.05:1)

2nd gear 2.67:1 (overall ratio: 24.88:1)

3rd gear 1.6:1 (overall ratio: 14.91:1)

4th gear 1.24:1 (overall ratio: 11.55:1)

Regardless of whether you feel a gearbox is necessary with an electric motor, two important benefits become apparent: Selecting 1st gear will help keep the bike from rolling away when parking on an incline.  Selecting neutral will make the bike much easier to push.

Clutch & Gearbox Fluids

The FACTOR-e User Manual is available under the Downloads section of the EM France website.  Its filename indicates version 1.0, which suggests there may be revisions in the future.  The MOTUL logo appears on all the pages, so it comes as no surprise that is the recommended brand of lubrication products. 

The manual is a bit confusing, so I will give my interpretation.   The clutch and gearbox fluids are separate and have different requirements (this is smart in my opinion).  Both clutch and gearbox require an initial change after 10 hours of use.   Both require 200 ml of fluid. 

The recommended fluid for the clutch is MOTUL ATF VI, changed every 20 hours.  According to Motul's datasheet, this is equivalent to a Dexron VI automatic transmission fluid.  Ignore the part about it being 75W.  

It is a common misconception that “W” stands for “weight” when referring to lubricating oils - it does not.  “W” refers to the  “winter” or low-temperature viscosity rating.   Also, gear oils and motor oils are classified differently.  A 75W gear oil has about the same kinematic viscosity as a 10W motor oil. 

The recommended fluid for the gearbox is MOTUL Transoil Expert 10W-40, changed every 60 hours.  To me, the important point here is to use an oil optimized for a gearbox.