Cam shaft timing

The red tooth indicates the cam shaft timing. It correlates with a + sign on the flywheel or swing wheel.

If you look closely on the red tooth, you will see that a corner is filed off.

When the plus on the flywheel rim is in the middle of the top hole of the swing wheel housing (where the mushromoid little cap is stuck down), the filed off tooth of the cam shaft wheel should be against a marking on the inside of the bell shaped part of the cam shaft housing The marking is a big minus-sign and it is opposite the oil return opening.

Now do inspect the dynamo CLOSELY. Its top wheel does ALSO have a filed off tooth. There should be a faint marking on the dynamo neck. The filed off tooth should be at that marking when assembling. If the marking is not there, we have a bit of a problem now... The reason why the marking is there is to ensure that the wheels have the same engagement. There is no 'hunting tooth' system on the Nimbus so it goes in the same engagement. If you change that engagement, you will get some howling from primarily the bottom and top engagement of the dynamo.