The BSA A7-A10 Forum

Technical => Lucas, Electrical, Ignition => Topic started by: BSA500 on 25.06. 2017 12:00

Title: Auto advance stuck and mag has issues
Post by: BSA500 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*
Title: Re: Auto advance stuck and mag has issues
Post by: duTch 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*
Title: Re: Auto advance stuck and mag has issues
Post by: BSA500 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*
Title: Re: Auto advance stuck and mag has issues
Post by: duTch on 25.06. 2017 13:31

 yep I understand, but can't think much else *dunno*..wish I could
Title: Re: Auto advance stuck and mag has issues
Post by: chaterlea25 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
Title: Re: Auto advance stuck and mag has issues
Post by: BSA500 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
Title: Re: Auto advance stuck and mag has issues
Post by: coater87 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
Title: Re: Auto advance stuck and mag has issues
Post by: Triton Thrasher 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?
Title: Re: Auto advance stuck and mag has issues
Post by: coater87 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
Title: Re: Auto advance stuck and mag has issues
Post by: Triton Thrasher on 25.06. 2017 14:11
Removing a shim reduces armature end float, unless you replace it with a thicker shim.
Title: Re: Auto advance stuck and mag has issues
Post by: BSA500 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*
Title: Re: Auto advance stuck and mag has issues
Post by: coater87 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*
Title: Re: Auto advance stuck and mag has issues
Post by: BSA500 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??
Title: Re: Auto advance stuck and mag has issues
Post by: BSA500 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.
Title: Re: Auto advance stuck and mag has issues
Post by: groily 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,
Title: Re: Auto advance stuck and mag has issues
Post by: BSA500 on 26.06. 2017 11:14
No wiggle on the armature that I can detect. It was rebuilt as recently as April and I am sending back to let the well renowned Andrew at Priory magneto's to cast his expert eye over. He is very good he has done a few rebuilds on dynamo's for me to a very high level.
Title: Re: Auto advance stuck and mag has issues
Post by: groily on 26.06. 2017 11:55
Problem solved then. Good plan! Summat funny must have happened then, as it certainly wouldn't have been like that when Andrew had done with it.
Title: Re: Auto advance stuck and mag has issues
Post by: BSA500 on 26.06. 2017 12:37
I know but recently I have had the DVR2 regulator fail,perhaps I am waiting to hear, they never fail. Since I rebuilt the engine/dynamo/magneto and carb I have never had some many issues. It was more reliable when it consumed more oil than petrol.
Title: Re: Auto advance stuck and mag has issues
Post by: BSA500 on 02.07. 2017 21:16
Magneto is repaired and on its way back. Andrew said the play wasn't too disastrous back the probelm starting was because the points had shut closed??. Never touched them so how?. Also some tracking along the slip ring. So he has worked his magic and has sent it back to me. 
Title: Re: Auto advance stuck and mag has issues
Post by: Triton Thrasher on 03.07. 2017 14:46
Points gaps have to be checked and adusted.

It's maintenance.
Title: Re: Auto advance stuck and mag has issues
Post by: BSA500 on 03.07. 2017 15:18
The mag had only been on the bike for a month or so and only 200 miles done. In the 27 years I have owned this bike it was generally a once a year job and even then they hadn't changed. So wasn't really looking to that as the reason behind the bikes difficult starting.
Title: Re: Auto advance stuck and mag has issues
Post by: Bsareg on 03.07. 2017 15:49
If they are new points then they settle down and bed in
Title: Re: Auto advance stuck and mag has issues
Post by: Triton Thrasher on 03.07. 2017 15:58
Next time a bike won't start, check plugs first, then points.

I notice you checked timing in Post #1. That would have been a godd time to check the gap.

Not trying to annoy you.  Bet it won't catch you out again.
Title: Re: Auto advance stuck and mag has issues
Post by: BSA500 on 03.07. 2017 16:23
Yeah did all the usual checks and at first no spark, then they returned rinse and repeat. Andrew did say there were a few issues so he replaced the slip ring/armature and pick up brushes just to be sure. He does a very good job. I was mislead into thinking it was fuel first off as the mag was only a couple of months post rebuild. We all miss the obvious if we don't look ;). I got led off piste with the points when I noticed the armature play and of course fixated on it
Title: Re: Auto advance stuck and mag has issues
Post by: BSA500 on 09.07. 2017 13:49
Mag back in starts first kick and ticks over as it should. There was a horrible noise first start, turned out the fibre gear was too tight  to the cam gear, a quick mounting bolt wiggle sorted that. Andrew did another great job with his skills etc around mags and also dynamo's.
Title: Re: Auto advance stuck and mag has issues
Post by: beezermacc on 10.07. 2017 06:52
Thanks for your kind remarks.