The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: Frenchy on 14.01. 2010 14:53
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Hi. I'm looking for the advance unit for a 59 A7. The stock Lucas K2F has been replaced with the Joe Hunt mag, but I can't find an advance unit for it.
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Can't see from pix on their web site whether the Joe Hunt thing has the same tapered shaft for the pinion or ATD as a Lucas. Can't see any shaft at all in fact in their pictures. Assuming it does, which it ought to as they are claimed to be a direct replacement in pre-unit applications, then you need the standard ATD unit unless there is any option for manual operation. Suspect there isn't, as weren't these things developed originally for industrial engines, which would normally run at pretty constant revs?
Getting an ATD looks easier said than done. Not sure where you are, but Draganfly in the UK do an exchange-only rebuild service (only of use if you can find a dead one somewhere). I thought SRM sold them complete but can't see them on their site as a complete unit, just various of the bits. But worth a call or e-mail to them I'd say. Haven't looked on e-bay because I hate the place, you probably have.
Maybe someone else here knows who's got 'em available without the need for an old one to exchange?
Doesn't sound as if 'original' is critical to you, so an alternative would be to find a Lucas manual mag and get it sorted (it will work for longer than many of us are going to live). Could probably get one and sort it out for the value of the thing you've got, looking at what they cost. Look a lot better on the bike, too.
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stock isn't important to me, especially if you've seen what my a7 looks like. i'm interested in getting a functional advance/retard unit for cold starts. i've gotten ahold of hawker magnetos about building me one, but it's almost $300. in the mean time i've found a manual gear that i'm going to use to replace the auto advance. i'm still confused as to how i'm going to attach it to the drive shaft, though. the taper is right and fits, but it appears that i need a double threaded nut to hold it in place. any advice?
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Frenchy,
If you have a genuine item, the internal thread is for a puller to remove the gear.
The thread on the Lucas magneto is 3/8 BSF. Joe Hunt probably uses something different.
Trev.
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Hi Frenchy,
The internal thread in the pinion is for threading in the extractor to remove the pinion!!
The magneto pinion holding nut is a deep nut normally with the inner portion turned down until its round
Its easy to make one from a bit of suitable hex bar, 3/8 BSF for lucas mag dont know about the Joe Hunt tho
Cheers
John O R
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Just spotted this on fleabay
no. 330397418612
HTH
John O R
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Thanks, everyone, I found one.