Author Topic: Auto advance stuck and mag has issues  (Read 1027 times)

Offline BSA500

  • Resident Legend
  • *****
  • Join Date: Dec 2007
  • Posts: 705
  • Karma: 4
  • Tonbridge,Kent,UK
Auto advance stuck and mag has issues
« on: 25.06. 2017 12:00 »
Following on from the stop charging thread I have started this new one because of a different issue-again!. The bike was being a pig to start 20-30 kicks. The magneto has been recently rebuilt by Priory mags so I suspected I had got the timing a little out. Checked yesterday and yes it was slightly retarded. No problem pop the auto advance off retime. Nope extractor will not extract, just keeps turning.
Groily's post had some ideas, pull on the bolt and turn no good. Loosen the mag and tap the end. I am not going to try that  *eek*. At this point I noticed the armature has got some in and out movement-what  *eek*.
Am I right there should be no in and out play ?. So the questions are should there be no play,if not I need Andrew to have a look at it. Of course that means I need to get it off the bike when the fibre pinion is refusing to come off. Any suggestions other than a quick cry and popping the whole bike in the post to Priory Magneto's.
Somedays I wish I stayed in bed  *sad2*

Offline duTch

  • Ricketty Rocketty Golden Flashback
  • Wise & Enlightened
  • *
  • Join Date: Oct 2011
  • Posts: 4540
  • Karma: 41
Re: Auto advance stuck and mag has issues
« Reply #1 on: 25.06. 2017 13:13 »

 
Quote
Am I right there should be no in and out play ?.

 I would not think so, if the pinion is up tight, and Maggy is still bolted on...otherwise Groily's idea sounds like a good option, so long as you think it through...

 The pinion/extractor nut should do the job; maybe it's just not quite engaging properly... *dunno*...mine comes off super-easy *conf*
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline BSA500

  • Resident Legend
  • *****
  • Join Date: Dec 2007
  • Posts: 705
  • Karma: 4
  • Tonbridge,Kent,UK
Re: Auto advance stuck and mag has issues
« Reply #2 on: 25.06. 2017 13:28 »
Mine has always come off super easy(had it for 27 years) up till now. Its just another thing to p**s me off. I just need to ride it. I have had the engine rebuilt/dynamo/carb and magneto. And in the space of 2 months dynamo reg seems to have failed-twice. Rewired to sort out sh***y mess it was in. Battery failed and now a pinion that has always come off reused and a mag that is barely done 200 miles has developed play. I have no doubt Andrew at Priory mags did a great job and if I can get it off I would gladly send it back for him to assess the problem. *sad2*

Offline duTch

  • Ricketty Rocketty Golden Flashback
  • Wise & Enlightened
  • *
  • Join Date: Oct 2011
  • Posts: 4540
  • Karma: 41
Re: Auto advance stuck and mag has issues
« Reply #3 on: 25.06. 2017 13:31 »

 yep I understand, but can't think much else *dunno*..wish I could
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline chaterlea25

  • Wise & Enlightened
  • *
  • Join Date: Jun 2009
  • Posts: 3216
  • Karma: 46
Re: Auto advance stuck and mag has issues
« Reply #4 on: 25.06. 2017 13:38 »
Hi,
Since you have to remove the mag anyway,
undo the mag holding nuts, screw the AA holding nut all the way in by hand and back off one full turn
A tap on the nut should release the AA unit

John
1961 Super Rocket
1963 RGS (ongoing)

Offline BSA500

  • Resident Legend
  • *****
  • Join Date: Dec 2007
  • Posts: 705
  • Karma: 4
  • Tonbridge,Kent,UK
Re: Auto advance stuck and mag has issues
« Reply #5 on: 25.06. 2017 13:54 »
Is there a chance of doing more damage doing that ?. Not keen on hitting the end of the armature

Offline coater87

  • Wise & Enlightened
  • *
  • Join Date: Jul 2008
  • Posts: 1181
  • Karma: 6
Re: Auto advance stuck and mag has issues
« Reply #6 on: 25.06. 2017 14:00 »
 Not a sledge hammer blow, a nice sharp rap should do it.

 Your bound up on the taper.

 If you follow johns advice, and screw the AA unit all the way in by hand, then back it out a full turn you should have enough play to pop the taper and enough threads in the armature to not damage anything.

 Just dont be a gorilla or a little girl about it. But staying on the little girl side is safer.... ;)

 Lee
Central Wisconsin in the U.S.

Online Triton Thrasher

  • Scotland
  • Wise & Enlightened
  • *
  • Join Date: Feb 2009
  • Posts: 1500
  • Karma: 20
Re: Auto advance stuck and mag has issues
« Reply #7 on: 25.06. 2017 14:04 »
Has the end piece that carries the cam ring and points end bearing come loose on its little countersunk screws?

Offline coater87

  • Wise & Enlightened
  • *
  • Join Date: Jul 2008
  • Posts: 1181
  • Karma: 6
Re: Auto advance stuck and mag has issues
« Reply #8 on: 25.06. 2017 14:06 »
 You should have end play in the mag. The guy who looked mine over felt I did not have enough end play and removed a shim to increase it.

 What that number should be is a mystery to me.

 I would think if you are not slopping back and for more than .010 you should be OK?  *dunno*

 Lee
Central Wisconsin in the U.S.

Online Triton Thrasher

  • Scotland
  • Wise & Enlightened
  • *
  • Join Date: Feb 2009
  • Posts: 1500
  • Karma: 20
Re: Auto advance stuck and mag has issues
« Reply #9 on: 25.06. 2017 14:11 »
Removing a shim reduces armature end float, unless you replace it with a thicker shim.

Offline BSA500

  • Resident Legend
  • *****
  • Join Date: Dec 2007
  • Posts: 705
  • Karma: 4
  • Tonbridge,Kent,UK
Re: Auto advance stuck and mag has issues
« Reply #10 on: 25.06. 2017 14:15 »
The play is visible I can see the points move in and out. I shall not try to be a little girl with the tap on the end  *smile*

Offline coater87

  • Wise & Enlightened
  • *
  • Join Date: Jul 2008
  • Posts: 1181
  • Karma: 6
Re: Auto advance stuck and mag has issues
« Reply #11 on: 25.06. 2017 14:18 »
Removing a shim reduces armature end float, unless you replace it with a thicker shim.

 You are correct sir!

 He removed a shim, so he must have felt I had too much. I am positive he removed and did not add. He would have charged me $50.00 for the extra shim, but gave me no discount for the shim he kept! *smile*
Central Wisconsin in the U.S.

Offline BSA500

  • Resident Legend
  • *****
  • Join Date: Dec 2007
  • Posts: 705
  • Karma: 4
  • Tonbridge,Kent,UK
Re: Auto advance stuck and mag has issues
« Reply #12 on: 25.06. 2017 16:50 »
I shall try to shift it later. If this fails has anyone tried the last method of drilling the hollow bolt,tapping and screwing in a bolt to push the armature out??

Offline BSA500

  • Resident Legend
  • *****
  • Join Date: Dec 2007
  • Posts: 705
  • Karma: 4
  • Tonbridge,Kent,UK
Re: Auto advance stuck and mag has issues
« Reply #13 on: 25.06. 2017 20:34 »
It has come off. A little leverage on the mag body, a sharp tap and hoorah. Thanks all. But the mag has 25 thou movement too much I think.

Online groily

  • Wise & Enlightened
  • *
  • Join Date: Jul 2007
  • Posts: 1076
  • Karma: 18
    • www.brightsparkmagnetos.com
Re: Auto advance stuck and mag has issues
« Reply #14 on: 26.06. 2017 10:57 »
Well done. But yes, too much endfloat. It will hammer its bearings like that and there must presumably be up and down wiggle on the armature?

Really, you want as close to no float as you can get, without ending up with negative. If there are shims between the cb end housing and the body you could try removing or shuffling the pack if there are several - but 25 thou is rather a lot to be taken up there. Probably needs more shimming behind the race of the bearing at the slipring end - but also very worth checking that the bearing outer races are being firmly held in their respective housings with good insulators.

The middle of the slipring ought to be in the middle of the windows for the pick-ups as well - if it's visibly off, might need to think about the shimming at both ends to get it central, though there isn't usually any shim at the non-slipring end. However, if the cb end housing isn't the original one, there can be small differences in fit, which all add up, depending on the bearing insulators in there, etc etc.

Unless you are pretty unlucky, the thread in the ATD yoke for the self extract will probably be OK and you'll just need a new centre bolt/screw. It's a godawful design as no-one with any sense would use the first turn of a left-hand thread you can't get at to prise anything off a taper, but it's what we're stuck with unfortunately and there isn't an easy redesign. I can't for the life of me think why they did it,
Bill