New low cost 7 plate racing clutch

[Rich_T]

I've just finished the first 10 Aprilia7 plate clutch conversions. It uses nearly all the parts from the donor RS125 Rotax 122 clutch, with a new crown wheel, new hub and modified basket. This is a low cost conversion ideally for racing application as it requires a side case packing plate. All wear parts are standard RS125. Full clutch is £260 or £230 if a replacement donor clutch is supplied. I'll attempt to put pictures up over the weekend, PM me if you're interested.

[Ruudboy]

let those pictures come!

[Rich_T]

[Rich_T]

I dry fitted the first clutch today to confirm packing plate size, kick start clearance and operation, pictures will follow shortly. Firstly it is a tight squeeze, the central pip of the kick start needs to be grown down to clear the larger clutch plates. The end plate bolts all have to be uniform and screwed in low to clear the lock nuts on the back of the crown wheel.

The release operation works best with a GP side case but Li series 1 & 2 can be used. The release plate used is the original Aprilia ball bearing, when used with the Li style release cam the point of contact with the ball bearings spherical surface changes. This actually makes the clutch feel lighter as it is pulled in further as the cam moves through it's arc. This is an odd sensation to me but some people might find it a benefit. The clutch is nice and light and fully releases with a very small amount of movement. The packing plate required is 10mm thick and allows for 2 good quality thick side case gaskets. Street machines will require extended kick starts, I'm told both of these parts are available from MBD.

Other than that it fits in perfect, no modifications required to the inside of the side case (like some of the old multiplate conversions).

[rocho68]

hi rich , will you sell parts individually ?

[Rich_T]

Thickness of packer measured at 10mm




Unlike the previous GT clutch, this low cost version has to be assembled into the engine, it was the only way to keep the price right down. No compression tools required.


You can see where the central pip on the kick start shaft has been removed. Importantly, the back of the shaft is only lightly touched to help clearance from the edge of the basket as the shafts vary in size quite a lot.

It isn't as compact or elegant a solution as the fully machind version, which is now 8 plates, but that is the trade you make if designing around as many low cost standard parts as possible.

[Rich_T]

hi rich , will you sell parts individually ?

Which parts? There are only 2 bespoke parts and one modified part plus one additional friction plate and steel. The modified basket has to be done on an exchange basis.

Are you proposing to get everything yourself, including modifying the basket and only buy the crown wheel and hub? This would be OK but do not underestimate the work required to modify the basket. At the very least it will require a lathe with 3 jaw chuck capable of holding circa 125mm diametre externally.

[twin peeks]

how much for the 10mm packer

[Rich_T]

I think MB were doing them for £50 last time I looked. There are others about though and some older clutch kits were already supplied with packersand extended kickstarts.

[WINTERMODEL150]

If the side casings moving out by 10mm then does the exhaust need to be moved out by 10mm as well?