[Chasfield]

Got the new auto advance springs and extractor tool. The auto unit came off in a few moments and shortly thereafter it was dismantled on the kitchen table. Guess what, the points cam carrier plate was bent all over the place (not by me) so that the slide pins wouldn't slide cleanly and worse, the one that hits the stop to control the degree of max advance couldn't make it all the way home, so the advance range was compressed a bit.

I gently bent the assembly back into a better shape (the metal is v. soft)and installed the new springs, which are noticeably more snappy than the old ones.

When I reinstall the unit tomorrow, I will be able to set a conservative static advance, to allow kick back free starting, without stifling performance at normal engine rpms.

I think another poster discovered that their auto advance had been mangled at some stage by a previous owner. I think this happens if somebody tries to lever the thing of without using the proper extractor tool.

[Chasfield]

I put the auto-advance unit back in, complete with snappier springs. It is interesting just how an engine's characteristics can change upon a slight alteration of a minor but critical part.

Yup, those new springs were too snappy. They drove the auto advance actuation threshold up the rev range, making the bike retarded and intractable at low engine speeds. Oh, and the engine still hiccuped and faltered once in a while, as before.

So I put the old springs back.

Unbending the auto advance plate, as per my last post, did slightly extend the range of auto advance available and my engine is now definitely a bit sweeter at all speeds. I had previously been vexed a bit by ignition timing issues: a static advance setting for easy starting stifled performance at higher revs.

BTW, if you want to check your auto advance mechanism but don't have the extractor tool, you can, with care, dismantle all the movable bits off the back plate without pulling it off the distributor shaft. If the central retaining allen bolt is removed, the movable bits are only then being held in place by the advance control springs. These can be unhooked and re-hooked with care.