|Bottom steering head bearing |
before waxy old grease
was cleaned out ...
|... and again after cleaning.|
Mucky residue visible in the pan.
The steering stem has a strange rectangular slot at its midpoint. I've no idea what this is for. My best guess is that it is something to do with the manufacturing process, maybe for clamping for insertion into the bottom yoke.
The top bearing just drops into its tapered seat in the top of the steering head. The seat was in great condition. Hooray! The bottom seat was also in fab condition. There is a rubber dust seal beneath the bottom bearing - it did a good job of keeping the grease in place so that's probably why. The steering stem passes through the steering head and top bearing, and is then retained in place by a threaded aluminium collar.
The collar on these early bikes is intended to be turned by hand to a point where vertical movement in the bearings is just eliminated, and no more. It is a judgement, this, made complicated by the stickiness of the grease. After two or three tightenings and slackening off, I was happy with the level of tension I'd put into them and the left-to-right movement of the steering action. So I lightly torqued up the M6 pinch bolt to the specified level.