Wipac alternator rotor

Not wanting to live up to the title above, but...

Electra uses a Wipac rotor with a larger bore than Jubilee and Navigator.

Wipac alternators were fitted to many types of m/c and other small engines so I'd be amazed if there were only two bore sizes for Wipac rotors.

Peter 

The Wipac rotor is known as 1" bore, or is this 31/32 or is this 24.6mm? Yes Wipac were fitted to many other machines but in all these years with Norton NO ONE has mentioned another size for Wipac inside. There is only the ONE size (as far as we know) Even if there was a 3/4-19mm version it would be 50yrs old (low magnetism).  I have looked at the Lucas rotor, as soon as you look at boring it out stop and think how it is made, how much metal will be left, how crucial is it to be safe? If it comes apart in service, you will loose charge, you will also seize your engine at speed and if you are lucky you might just fall off. Another small point as the Wipac is a few mm smaller than the Lucas then the Lucas rotor inside the Wipac would interfere. If you can get a batch of said Lucas rotors bored out with a 10 year guarantee I will have a box full.

..lists the complete alternator with a Norton number 24865, and another presumably Wipac number G1697. 

The bare rotor is only listed with a Norton #, S0734.

Not sure how this helps, but now you know... 

The crank dimensions are THE SAME on all 3 models, so the magnetic rotor is ALSO the same on all 3 models (Jubilee, Navigator & Electra). However, the stator (coils) are different for the Electra (it is wired 2 coils + 4 coils), as opposed to the Navi & Jubilee (3coils + 3coils).

The crank dimensions are 0.9670" to 0.9675" - which, as you can all see, is a whisker less than 1"

My details are in RoadHolder under "Tech Advice"

So sorry. The Wipac rotor of the Electra is the same as measured by John.

Just measured both.

Thank you to all for reminding me not post rubbish.

Peter 

.....But don't do it again!

Yes Commando is a 3/4" crank for rotor.

ALL the Lucas rotors are 19mm bore. Prior to 1960 (or there about) the outside was 70mm. The later ones are all 74mm. 54212006 rotor was prone to coming apart, and perhaps earlier ones.

54201143, 54202298,  54202299,  54212298.  These are all thought to be Hot riveted, hence NOT prone to flying apart.  All Lucas rotors are magnetically identical. 3 phase is 9 pole pieces (not just 3 wires)

I did say I 'thought' they were hot riveted. But the snag here is that we don't find out until it's too late. I have some reasonable conversant alternator numbering but NOT a definitive listing. Does any one else have info.

Why is this thread still running?

The Lucas Rotor, as stated above, has a 3/4" bore.

The Wipac Rotor is a whisker under 1" - there is no way that you are going to bore out a Lucas Rotor to suit an Electra crank (whose dimensions are 0.9670" to 0.9675") without compromising it. Early Lucas Rotors were known to fly apart even without assistance!

In addition, the Wipac Rotors are more robust (they never flew apart, or got loose on the central spacer) - and keep their magnetism better as well.

If you do not have an alternator at all on your Electra, try & find one on eBay. If you find the stator coils are damaged/burnt out/shorting to ground/whatever - then replace it with a 2-wire 12 Volt stator from Lucas. Wassell import them at present (from India?). They are well made & good value.

The airgap will be slightly larger than with the original Wipac Stator, so Power produced will be lower - but with modern LED headlight bulbs, that should not be an issue.

I would also suggest you use a modern Rectifier/Regulator, rather than the mechanical curiosity under your seat - hence I suggest a 2-wire stator. Good Luck