LUCAS 43D4 (which means it is identical to the Lucas 45D4, but without vacuum advance).

Note my opinion: checking all this is one thing; changing anything is quite another.

No points in mine and electronic ignition igniter is removed (fitting a new one).

To check the "bushes"; rotor off,

push down on the "pole", there should be no movement.

push it sideways, there should be a little bit of wiggle, but no slop and not too much wiggle.

Right down at the bottom inside the engine is a round bit that should have a tiny bit of play (measured in "thou") and nothing more: but that means lifting the dizzy out completely and I have avoided doing this, so far. It is cheap to replace.

Dizzy cap off: Under the round plate that is held in with two screws (it's called the "breaker plate") is the "mechanical advance" mechanism. There are two springs. One spring is slightly under tension and may be a different size to the other (mine is smaller). The other is loose and mine is larger than the other one. When you turn the mechanism (very easy, one finger no problem) both springs should be "engaged" so the loose one will come in to play. 

Mine seem to be "ok"

I was told today that "they" don't change the springs if they can avoid it. For a start they need the serial number off the side of the dizzy "case" and if that has been scratched out it means the dizzy has been modified and to go one from there requires ALL the spec of the cam etc, which may well not be standard.

As regards the spring that is mean to be "pre-engaged", and it isn't, bend the bit that hooks round its holder to effectively shorten it and bring it back in to play. Rough and ready. Seems to me this is all very well for someone who has vast experience of hundreds of these; for someone who has never done any of this I think sending it in for refurb is the wiser choice. www.distributordoctor.com

Comments and corrections very welcome while I still have edit rights.