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I think this a previous problem BUT I would like some more information please.

Has anyone had a modern so called Lucas stator 'melt'? IE the green encapsulation appears to melt and therefore the green 'gundge' gets in the gap and generally causes 'avock' .

Please PM


The voltage regulator type would be also useful, it could be the melting alternators are caused by modern voltage regulators instead of the Wassel sourcing policy. All my alternators are original or LAP UK made and no failures including the 1980's 3 phase one with a modern Mosfet based regulator.

Good afternoon Al, hope all is well in sunny Norfolk.

I thought you knew me well enough to realise when I'm being facetious! Perhaps we need the Webmaster to enable emojis!!


Very best regards mate.


Silly boy-Michael

Good point John-but modern stators should stand up to modern regulators.


Sorry to butt in here but what Al is looking for is not reasons why or how to prevent it, but details of people who have had the problem.

It would be useful to know details of charging system, how long you have been using it and anything else relevant.

I too am interested to hear.



but modern stators should stand up to modern regulators


Its a Wassell copy of a Lucas design last updated in the dying days of the Meriden Co-op when the 3 phase version was introduced. All had the voltage regulated by Zeners in some form even the 3 phase in a negatively wired bike. I would not define it as modern. I suspect there is a flaw in these Green Box alternators that makes them melt caused by a change in the production process to suit the supplier, but as modern regulators now shunt to regulate rather than produce heat this could also be a cause.


Correct Tony, I just want to hear from any one (no one so far) who has had a stator 'melt'.

BUT-3 Phase is nothing to do with it nor is negative earth. The shunt regulator is involved but not necessarily the problem, BUT the stator must be up the job it is intended for, other wise it is not fit for purpose.


BUT-3 Phase is nothing to do with it nor is negative earth. 

Read what I posted again, I do not say all 3 phase alts are only negatively earthed bikes just a negatively earthed bike from the Tri Co-op. The negatively earthed T140 with 3 phase did come with a nifty tripe zener pack, when the Co op did the change I did the same to my Commando and went 3 phase negative earth with that triple Zener pack, the same 3 phase alternator is now running positive earth with Mosfet reg/rect.


I have a green potted one. It's been there for years and given no problems, so that is one negative.

It had Boyer Power Box for a long time. Now ot has one of yours!


Yes, I have helped quite a few people out with damaged stators.


Usually the melted ones are caused by poor clearance between rotor and stator or bad alignment.


More often than not, these are brand new Lucas (Wassel) stators that have recently been fitted.



Electrical issues are different - they usually result in the resin cracking out not melting. It’s easy to spot the difference.

I've noticed the gap between my commando rotor and stator reduce, and finally 3 weeks ago it had meltdown and locked the engine. Not sure if this was do to the rotor anomalies (migrating magnets) described elsewhere. Ordered replacement parts from NOC spares, super service guys, received in France 10 days later (faster than recent Norvil and other supplier deliveries). New gap was on the 8 thou limit, so took it easy, and 5 miles out, it started to nip up again. Didn't notice any play at the end of crankshaft but I fear that's where I'm looking next.



Green stators in green boxes are no longer, it is now back to the brown version but I am not sure they are LAP. Lucas now has a new owner who are shaking things up a bit. 

Good information re stators and closing gaps! Keep me/us informed please. Interesting to see Ashleys comment re the stator material. Migrating magnets can usually by seen by them lifting which in turn can be discerned by feeling with the finger nail. Grey dust from the centre steel 'mount' is another give away, but that hasn't been seen for some time.


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