Vespa Post 1979 Large Frame Engine Work

Clutch Rebuild

Usually when the clutch is not functioning well, nine times out of ten the plates need to be replaced. These images are from a P200 clutch but large frame clutches are similar but may have different amounts of springs. Once the clutch has been removed changing the plates and any other work is easy. You'll need:

  • A pint of SAE 30 transmission oil.
  • 3 new cork clutch plates (soak in oil before installing).
  • New springs (might as well)!
  • A clutch compressor tool or a home made version from typical hardware store items.
  • Two inner brass bushes (cheap and good to replace)

A special Vespa clutch compressor is a nice tool, but you can make one for under $4 at your local hardware store from standard nuts, bolts and washers. You are looking for:

  • A hex head bolt of between #10 and 3/8" (6mm - 10mm) about 2" (5cm) long.
  • A nut for the above bolt
  • 2 washers with an outside diameter not more than an inch You may have to build these up as shown in the example above.

Above is a view of a compressor I made from parts in the garage. Take the clutch with you to the hardware store to be sure of getting the right bits.

 

Put the clutch compressor through the central crank hole. Make sure the washer on the side with the spring holes is totally covering the central hole, and then tighten up the compressor. You only need to tighten it enough so that the pressure on the circular perimeter retaining ring is released. Remove the ring by pulling it out of the groove.

Once the ring is removed, the first one sided cork plate can be removed. This plate differs from all the other plates because it has different shaped tabs and must be the last plate installed. These tabs lock the cork plates to the outer basket. The next plate is a full steel plate which is teethed around the interior perimeter to lock it to the clutch center. Remove all the free alternating steel and cork clutch plates.

The final steel clutch plate is riveted to the clutch center gear. The clutch compressor needs to be removed in order to remove the center gear from the basket and to get access to the springs. Once the compressor is removed I usually get a large socket to set the clutch on so that the spring cups are not touching the work surface.

The clutch center gear and plate should be easily removable from the main clutch body. In the clutch above the brass bush came off with the center plate instead of remaining on the body, but I'll describe what should go where in the next couple of steps.

Remove the small brass bushing. These are very cheap and easy to get through a scooter dealer and should always be replaced when doing clutch work.

Remove the main clutch body and the springs and spring cups will be visible. You can see the large socket in the center supporting the clutch basket. This makes it easy to deal with the spring caps because they will be held in place by gravity. If you bought new springs remove the old ones and place the new ones in the cups.

Inspect the clutch main body for wear. The interior components of the clutch don't run on bearings, but run on brass bushes at the friction points. This clutch had a cracked brass bushing which allowed the bushing to slightly expand in size and lock to the clutch center gear instead. I'm not sure how the damage above happened on the surface of where the bushing should be, but this entire part should be replaced and a new brass bushing will be added to the new piece.

The cracked bushing can be driven out of the clutch center gear by using a suitable sized socket and hammer to pound it out from the back side. In order not to bend the steel plate, don't support the piece by the plate while pounding the bushing. Usually they are a loose fit and just holding the center in your hand is enough support to bang it out.

Fit a new brash bushing to the main clutch body. This should be a nice tight fit so the bushing does not turn. Use a large socket or flat piece of metal to tap it until the lips are flush.

Then fit the second brass bush ring with the small lip facing upwards. This is a very loose fit and can rotate freely.

Place the main clutch center over the springs so that they seat in the recesses on the back side. I have always aligned the two holes shown above with arrows but I don't know if it really makes a difference.

Fit the main clutch center and spin it to be sure it rotates well. Above is a shot of the clutch plates in their correct order from left to right.

Fit the first cork plate and make sure the tabs are closely aligned with the tabs of the main clutch as it will make them easier to drop down in the basket when the clutch is compressed.

Fit a steel plate which interfaces with clutch center teeth. Keep alternating cork and steel plates until you get to the final one side cork plate.

Once all the plates are in and the final one side cork plate fitted, compress the clutch and help all the cork plate steel tabs drop down in the clutch basket.

Finally, fit the retaining ring in the groove in the clutch basket and your clutch is ready to reinstall.