 |
||||||||||||||||||
 |
||||||||||||||||||
 |
 |
 |
 |
 |
 |
 |
||||||||||||
 |
 |
 |
 |
 |
 |
|||||||||||||
Vespa Pre 1979 Large Frame Engine WorkBearings - Crank Bearings |
Main (Crank) BearingsOlder large frame Vespas use the same bearings on either side of the crankshaft. Once the cases are split and the crank and oil seal have been removed you can replace these bearings. The bearings are part number 900100 and their size is 25x62x12.
Above is a shot of the main crank bearing left in the dutch side of the casing. It definitely needs to be replaced, the casings need to be cleaned, and then a new bearing needs to be installed. Typically the flywheel side bearing will remain on the crank and the clutch side bearing will remain in the casing.
Once the oil seal has been removed, use a socket or something similar to drive the bearing from the clutch side by hitting it with a hammer.
The above is a shot shows the bearing being driven through the casing and getting close to coming out.
Clean the casings once all the bearings are removed if yours looks anything like what I started with. You can also install the oil seal from this side (see oil seal installation page) or just do it from the other side after the bearing is in place. Heat the casings beforehand to make the aluminum expand a little. There is no front or back side difference to the bearing so it can go in either way.
A useful tip is to use the original bearing that was removed as a drift to install the new one. Carefully tap down the new bearing so that it seats squarely in the hole. | |||||||||||||||||
