Mag / Flywheel bearing installation

Here's the bits that go into the magneto housing. An outer oil seal, a cup to retain the outer seal, the bearing, a larger inner oil seal, and a big meaty circlip to keep everything in.

My photo doesn't show them in any order:



There were no problems slotting all this into place - again I used the old bearing as a help, but the big circlip was a problem for my puny circlip pliers. Here it is all greased up and ready:



I used nyloc stainless nuts to fit the mag housing, and grease on the gasket for a tight seal but to aid future removal. When fitted I checked there was no rubbing against the crack using a feeler gauge:

Mag housing

This is the view from the back of the mag housing, showing the crankshaft bearing. Beneath the oily mess you can see the oil seal and huge circlip holding it all in. I had trouble removing this circlip as my circlip pliers weren't up to the job. I had to resort to standard long-nose pliers and a screwdriver. So much for 'the right tools'!





To remove the bearing I used a suitable-sized socket and a mallet to hammer it all out.

Flywheel removal

Here's a tool you can't do without, a flywheel puller. I got it from MB Developments and it's top quality.



It threads into the flywheel, and then a bolt is wound through the centre to push it out from the end of the crankshaft. There are a few methods of holding the flywheel in place while you do this. Whatever you do don't wedge something between the cooling fins, as they will break off!



I chose to insert a bar into the cylinder through the inlet port to stop the piston moving and therefore the crank turning. With hindsight I should have used a plastic or wooden object as there is a risk here of marking the cylinder or port.

When the flywheel is off you'll see the stator plate. This is held on with three set screws and is easily removed along with the wiring. Then you can remove the mag housing by undoing the three bolts and knocking it away with a wooden mallet.



Behind the mag housing you'll see the crankshaft in all its glory: