Fibre plates are 2.73mm when new
Steel plates are 1.53mm when new
Clutch pressure plate is 5.30mm from where the friction plate makes contact to the outer edge.
Clutch hub is 3.00mm from where the friction plate makes contact to the machined outer edge
2014 Factory > 2016:
As above, but these used 4 x standard 2.73mm frictions, and 2 x 3.00mm thick racing fibre plates.
- Old oil / Oil type. This is the first thing to change, the majority of clutch problems are due to the oil type and not been changed recently.
- The hub can get quite grooved where the steel plates sit causing problems with clutch slipping and sticking.
- The basket is prone to getting grooves where the friction plates sit, again causing problems with clutch slipping and sticking.
- Clutch springs can loose their springiness, the free length of the spring from new should be 45mm, if they get below 44mm they will cause slippage in high gears under high load.
If the spring have shrunk replace the springs https://www.splatshop.co.uk/sherco-clutch-springs.html or we do some washers to put extra tension on the springs https://www.splatshop.co.uk/shim-washer-14x20x1-din-988.html
- The friction face's on the hub and the pressure plate been out of square, if you have the equipment it might be worth clocking up the friction face and the clamping face to ensure they are parallel to each other, if not you can give the friction faces a quick clean up on the lathe assuming there is enough material left. With these faces being made of aluminium they usually wear more than the friction plates.
When the bike is new, change the oil more frequently to flush out any metal debris, then I personally change my gear oil every few months so it probably gets changed about every 20 times I ride the bike, this helps keep the clutch working well.
The oil type makes quite a noticeable difference to the response of the Clutch, Putoline Nano Trans GP is the best oil we've tried in the Sherco, especially with the clutch, it's pretty good with the gear shifting too and it seams to work for a long time before it needs changing. https://www.splatshop.co.uk/putoline-nano-trans-gp.html
Missing Washer (Major clutch slippage):
See the picture below for the washer that might be missing that causes very bad clutch slippage (highlighted in red) https://www.splatshop.co.uk/sherco-washer-a82035.html
This washer behind the clutch hub should also be 1mm thick
The clutch thrust bearing is 2mm thick
The washer for the above bearing is 1mm thick