Hi Bob,
The clutch outer is secured to the clutch inner with a single retaining screw. The screw is located on the engine side of the drive shaft (i.e. inside the clutch itself). It is easier to undo the nuts on the main frame stays (engine side), draw the stays back (on the chain side) and drop several of the tube spacers out on both stays and retract the engine. When retracting the engine be careful as there are two small springs in the clutch drive dog on the engine. You will also need to take note of which spacers and washers go where. Once you have retracted far the engine far enough you should be able to get a screwdriver in and undo the internal screw. Once the screw is undone, the clutch outer should then come away easily and enable you to clean the inside surface. Reassembly is the reverse process.
I hope that this helps.
Cheers,
Sir Chook
