I think the internal taper of my Mag Pinion is worn (hopefully not the shaft of the Mag) as it is too easy to extract from the shaft.
I can push the pinion fully onto the shaft by hand and pull it back off the shaft without the puller.
I have taken a small amount of metal off the pinion, but this does not seem to have helped.
I can time the bike and the timing will stay where I set it. However, I have always had difficulty getting the timing spot on; it would seem because of this.
I'm not sure I can see how any wear can take place on either taper? Once locked together there nothing to wear between them. If the pinion should ever come loose for some reason, then the engine would stop and again I don't think any real wear can happen. Have you tried tightening it up properly with a spanner? They don't take much to lock together.
Maybe your mag is not positioned correctly on the platform? Also there is the oil seal to contend with! Also a light lapping of the pinion with fine grinding past will eliminate any irregularities in the surfaces.
When you have the piston and points block in the correct position, try gently tapping the pinion onto the taper with a socket to get it started on the taper. As I've said before, I feel lucky to get it right within 5-6 goes.
I reckon anyone who does it by the 'book' and doesn't re-check it.....Will have it wrong!!
The pinion is not new to me, but looks a lot newer than the other gears.
It will lock on and I have done say 3,000 miles at least without it slipping; though I have fettled a few times in between. It did completely slip a couple of years ago and the bike popped and spluttered to a standstill.
Roger - how did you get round your problem? Another pinion that fitted better?
Ron - what should I look for to ensure my mag is positioned correctly on the platform?
Pat it's a case of making sure the mag is tight behind the timing case so that enough armature spigot is poking into the timing chest. Also the platform can become worn after heavy mileage with a loose mag strap. So make sure the pinion and idler teeth are not bottoming out on each other. You can get over this with some shim stock under the mag to lift it. It's all worth spending a bit of time over for trouble free running. Ron
Maybe I was a bit tired last night, but went back to timing it after my postings and now have the timing spot on! Well spot on for me. Hope it stays there.
