• remove rear wheel

• remove left foot rest support plate and exhaust muffler together

• remove the front hose cap, retain the hoses and remove the front lid of the chain housing.
• 
  This lid features the aeration of the chain housing. Check its condition and free passage of air. 

  Tip: If you connect the breather pipe to the upper port (blind) of the frame suction of the engine will put a low vacuum on the casing enhancing its tightness.

• remove the front chain sprocket.

• remove the rear swing arm bolts at the rear swing arm bearing and at the monoshock.

• remove the rear swing arm together with the chain housing. 

Now the rivetted chain link can be opened and the chain removed.

Take the rear housing apart and replace the large shaft seal. 

In case the grease appears to be very thinit is very well possible that the shaft seal at the front chain sprocket (driven side) is leaking engine oil into the chain housing thus diluting it. This wil mean you have hit the jackpot: Remove alle the grease and oil and replace it with Shell Alvania 1.

When replacing the shaft seal at the gear box / engine (driven side), take care not to sink it  into the engine housing as it has no stop inside. Just fit it flush with the outer housing surface.

Tip: Sahft Seals can easily be removed by hitting a SPAX-screw into the metal ring, screwing it in and by pulling it outwards. 

In order to relieve the aluminum threads from wear, be sure to lock two short M6 bolts securing the rear housing to the swing arm with loctite or an epoxyd into the swing arm. Then for fixation use a cap nut with washer and a snap ring. Be sure to use good quality, preferably stainless steel quality for theses parts. 

Tip: This procedure is perfect also for repairing the valve cover screwsa in case on of the bearings is screwed up, as the thread reaches in 5mm more tahn the original bolts!