The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: Strana on 29.04. 2023 22:18
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Hi all.
I am trying to remove the magneto drive pinion of my A10.
The pinion is fitted with the auto advance unit i belive. But when i unscrew the retaining nut , the nut comes off but the pinion stays in place.
Any ideas or tips on how to detach that pinion?
Any help would be greatly appreciated.
Thanks.
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Hi Strana, Did the nut come away altogether, or just come loose. If you keep turning anti-clockwise it acts as an extractor and should pull it off the taper. If it doesn't, the extractor LH thread may be too damaged, which is fairly common.
Col
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Hi Col.
Thanks for the reply. I am after realising that the nut has no thread from the outside. I am going to order a new nut and a pinion extractor just in case from De Groot today.
thanks again for your help Col.
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Magneto Pinion extractor is only of use with the fixed magneto drive gear used with Manual Advance maggys. Sure it is Auto Advance?
If so, a homespun claw type extractor should do the trick, along with gentle heat if required, not the traditional smack with the hammer. Avoid both if you can.
Make the jaws tips not less than an inch apart. This means they they will reach well behind the gear and will act on the central metal boss, and not the fragile fibre gear.
That ATD was supposed to be self extracting, so no official Lucas or BSA tool for the job was ever marketed.
Swarfy.
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As with Swarfy, no clobbering with a hammer. I did, however, find that applying some careful pressure to the unit and tapping round with a small hammer (not on the more delicate parts!!), did encourage the unit to release from the taper.
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The pinion is fitted with the auto advance unit i belive.
You believe - a pic would be useful. As Swarfy says, an ATD is self-extracting so, if your retaining nut has no outside thread, a new nut, screwed in ANTI clockwise, should pull it off. If, however, what you've got there is just a gear, then there is a puller which screws into the gear for extraction purposes (the latter presumes the gear is similar to the singles).
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Hi all.
Thanks for the replies.
I have sent a pic of the retaining nut that was fitted in the auto advance unit.
It seems it has been welded and has no thread.
I have ordered a new one and hopefully that should solve the problem.
Thank you all.
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Hi Strana,
Just checking that you ordered a longer one for the A10. Lucas made a shorter one for other bikes fitted with ATD's.
You also should get the large dished washer and the C-shaped washer which goes under the head of the nut.
Col
mod edit: the 3 bits Col mentions https://www.classicbikespares.com.au/product/lucas-magneto-atd-washer-disc-cover/
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Hi All,
unfortunately I need to remove the K2F magneto pinion
I would like to make an extractor for this alloy gear, but i don't know the thread size.
I found different sizes BSC threads, which is the right one?
5/8" x 20TPI
11/16" x 20TPI
and for the 67-0540 pinion 1"x20TPI
(based on my measurement the 5/8"x20TPI is the right)
Could you help me?
Thanks
Norbert
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G'day CZ.
11/16" x 20 tpi but why make one when forum member CheeserBeezer ( https://sites.google.com/site/priorymagnetos/accessories-and-running-gear ) has them for the best price I've found.
Magneto pinion extractor, BSA B31/ Gold Star / A10SR / A7SS / M 20, PMT008, 61-1903, ￡14.50.
Then there's EvilBay https://www.ebay.com.au/itm/193033147352 says 11/16" x 20 tpi
Cheers
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It is right, I ordered the puller.
Now I just have to wait to get it, and what a terrible truth will be revealed about the inside of the magneto.
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It is right, I ordered the puller.
Now I just have to wait to get it, and what a terrible truth will be revealed about the inside of the magneto.
If it's bad, just post the issue here and I'm sure offers of help will be forthcoming!