The BSA A7-A10 Forum

Technical => Lucas, Electrical, Ignition => Topic started by: baz123 on 11.02. 2017 19:10

Title: a7 not starting
Post by: baz123 on 11.02. 2017 19:10
hi everybody  I am new to the forum and looking for some help I've had a 1959 a7 ss  in the shed for a few years I have recently tried to get it running right it will only start if I take one of the HT leads off then it starts first kick on the cylinder that's still connected and the same if I do it on the other side but when both HT leads are on it coughs and back fires the timing seems ok ? any advice please.
regards Baz.
Title: Re: a7 not starting
Post by: muskrat on 11.02. 2017 20:32
G'day Baz  *welcome*.
I'm certainly no expert on magy's but my first thought is a dirtyslip ring or the camring is out of whack. Is it auto or manual advance? (an SS should be manual).
Cheers

Now go to Pictures, Stories & Intros and give us your story.
Title: Re: a7 not starting
Post by: baz123 on 11.02. 2017 20:45
thanks for the reply  the shooting star has auto advance










thanks for the reply

the shooting star has auto advance . I checked the cam ring plus pick ups and bushes all look good.








Title: Re: a7 not starting
Post by: beezermacc on 11.02. 2017 22:23
Even if the slip ring looks good I'm pretty sure this is dirty slip ring caused by poor quality brushes. Wrap some emery over the end of some rubber tube and push it through one of the pickup windows, turn the engine over slowly to clean the slip ring.
Title: Re: a7 not starting
Post by: muskrat on 12.02. 2017 06:25
Baz, when it comes to magy or electrickery beezermacc is your FRIEND.
Cheers
Title: Re: a7 not starting
Post by: Triton Thrasher on 12.02. 2017 09:45
Those symptoms are a dirty slip ring. 

Make sure you know which part is the slip ring before you clean it with cloth and petrol or alcohol.

And remove the points or earth the kill wire before turning the engine with your finger in the HT pickup hole.
Title: Re: a7 not starting
Post by: baz123 on 12.02. 2017 09:49
thanks for the replies I will give the slip ring a good clean . will let you know how it goes.
cheers.
Title: Re: a7 not starting
Post by: baz123 on 12.02. 2017 12:40
SORTED  took your advice and cleaned the slip ring and started first time I have noticed the bushes on the pickups are to soft so they are clogging the slip ring with carbon causing electric tracking . Will buy some new ones that are a bit harder.
thanks to everyone.
Title: Re: a7 not starting
Post by: Bsareg on 12.02. 2017 13:00
There are lots of crap brushes on the market, much too soft, seem to coat the slip ring so spark goes to the easiest plug to spark
Title: Re: a7 not starting
Post by: beezermacc on 12.02. 2017 13:05
I stock brushes which I know are OK. If you let me have your address by way of a PM I'll send you some for free!
Title: Re: a7 not starting
Post by: baz123 on 12.02. 2017 15:06
CHEERS BEEZERMACC
SENT YOU PM MUCH APPRECIATED.I OWE YOU ONE
Title: Re: a7 not starting
Post by: beezermacc on 13.02. 2017 10:55
CHEERS BEEZERMACC
SENT YOU PM MUCH APPRECIATED.I OWE YOU ONE

Can't find your PM ! Just give me a ring or send an e-mail using the contact details on my website.  www.priorymagnetos.co.uk
Title: Re: a7 not starting
Post by: baz123 on 18.02. 2017 12:58
received the new brushes from beezermacc much better quality than the old ones .

Thanks BEEZERMACC.
Title: Re: a7 not starting
Post by: duTch on 18.02. 2017 20:52

 I had a similar experience on two occasions a couple of months ago when mine got wet, once when I washed it, and then when we were rained on. Took several goes at cleaning the slip-ring but now all back to normal- which is an intermittent miss at idle, been doing it for some time and not always but no big deal just annoying but probably a carby thing so won't get involved here.
Title: Re: a7 not starting
Post by: edboy on 18.02. 2017 22:19
beezermack , are these new lucas contact brushs on ebay ok or some of the poor quality bunch. i ve had idle rougth running but runs perfect at top end speeds . i ve cleaned points etc but can t quite put my finger on cause .
Title: Re: a7 not starting
Post by: Bsareg on 19.02. 2017 00:18
My nephew bought some crap brushes from eBay.  When you know a good supplier, why chance It?
Title: Re: a7 not starting
Post by: edboy on 19.02. 2017 18:47
there are quite a few ressurrected items now sold new under the lucas banner. i have no idea if they are linked to the original company and making bits to original spec? or india copies?
Title: Re: a7 not starting
Post by: beezermacc on 19.02. 2017 21:33
To answer Edboy's question..........
Wassells sell new pickups complete with brushes. I've had problems with some of the brushes 'powdering' that come c/w the pickups so I always chuck those brushes. The powdering contaminates the slip ring and in the worst cases fills the slip ring housing with dust which prevents the mag working properly, sometimes even after you've cleaned the slip ring. Wassells also used to sell brushes individually, unbranded. I've never had any problem with those, I use them in all my magneto refurbs and never had any problems on any of my magnetos or anybody else's. I've done thousands of miles on my black A10 using a magneto with those brushes and never had to touch it. Wassells now sell brushes in 'Lucas' branded boxes, usually boxes of 5 brushes. These brushes seem identical to the ones previously sold unbranded and, again, I've had no problem with these. BUT they are not the same as the original Lucas brushes which were slightly longer, had lighter springs, and a groove down the side of the carbon brush. There are various brushes sold on Ebay. Researching the market (i.e. buying a few brushes from competitors on Ebay!) I find that some of the brushes are fine - they are the Wassells ones - and some brushes are the ones unscrupulous persons are selling because they know they are cr4p! Some Ebay traders are obviously offloading the brushes they have removed from Wassells pickups! Brushes I have bought from a well known supplier of magneto parts in the UK are also identical to the Wassells ones which are OK. One issue with the Wassells brushes is spring tension. The springs are much stronger than the original Lucas brushes, but they are shorter and I have found, from personal experience, that this doesn't matter provided you are not tempted to stretch the spring too much before fitting. It is worth checking that new brushes are only making light contact with the slip ring; this is quite easy as you can feel the brush hit the slip ring when fitting the pickup - a couple of mm pressure is plenty as the new brushes are very hard, as they should be. If spring pressure is too great you end up with a groove in the soft part of the slip ring which causes the brush to bounce as it hits the brass conductor and the brush wears out due to it bouncing up and down in the pickup. The new slip rings, UK supplied, are much better than the original Lucas ones as the plastic doesn't groove or crack. I have received quite a few magnetos for rebuild where the only problem is 5hitty pickups!
Title: Re: a7 not starting
Post by: groily on 19.02. 2017 22:22
Total agreement with every single word of Beezermacc's post as our experience is identical on every point he makes.
Lots of magnetos are still out there with carbon dust tracking problems and sometimes with sliprings impregnated to the point they need lightly skimming in the lathe to get them properly clean - and with lousy cheap pick-ups as well, which leak when tested hot  - from brand new - for lack of adequate dielectric strength.
Not sure if general resellers of these things are just unaware of the problem, or deliberately unscrupulous (bit of both probably) but the problem has been around quite long enough now for the honest injuns (at least) to withdraw them from sale.