A7 Magneto M/A service suggestions?

[Hughsie]

Hi All
Hope you’re all doing well.
I’m looking to try and improve my BSA Spark.
I seem to have a regular sleepy right hand cylinder when starting some times.
(I was out a couple of weeks ago and bike ran great, then today would only run on one side)
I am now always in the habit of draining the sump before I start it if it’s been sitting for more than a couple of weeks.

I always feel the spark on the right is not as strong so I’m making a few changes based on this forum previous discussions. I’ll post my ideas below.

But for now. I want to give my mag a service/clean as such. (Mag was rebuilt a few years ago so hopefully still in good order)
I do have a bit of oil over the mag, that’s escaped from the engine (engine was also rebuild, but still seems to be a bit oily)
What would you recommend I clean the mag with. I’m thinking I should remove the pick ups and clean the ring. What with? Maybe White spirit and a cotton bud thingy?
Also I’ve read I should remove the earth pickup, and clean the pickup and inside there? Is that’s the brass screw on top?
Also should I clean the points with some sort of cleaner or spray etc? Any suggestions? I’m sure my dad talked about point cleaner years ago.

As for the mag upgrades. I’ve ordered new leads and spark plug caps. The leads on mine are missing matched in length. At the moment my right lead (one that doesn’t alway fire up) is longer and going to the bottom pick up. And the top pick up is a shorter lead going to the left plug.
Does this make a huge difference?
I am going to swap these and make the leads similar lengths. I’ve also ordered a bit pipe to add more heat protection to the leads.
My last thought was just to also replace
The pick ups from bright spark and I see these get a good name.
I’m also replacing the plugs with champion n4c this time (I have the alloy head)
Also I’ve ordered boots to cover the acorns as I wonder if much oil is getting down there.

Can I clean the pick ups with something, or best just to replace.
Any other suggestions?

Ps in Scotland and temp is always cold lol.
Anyone around the Falkirk area?

Thanks in advance for taking time to read and to all that find the time to reply.

[CheeserBeezer]

Problems with firing unevenly is often due to dirty slip ring caused by poor quality brushes in the pickups. Original brushes have a groove down the side and they are OK. Brushes in Wassells 'white box' pickups are too soft and eventually draw a carbon line around your slip ring. Aftermarket brushes bought from reputable sources should be OK but beware of brushes which have a glazed appearance and draw like a pencil. Take the pickups out and clean the slip ring with some emery wrapped over the end of a piece of pipe. Remove the earth brush and clean the earth track with a cotton bud soaked in meths or brake cleaner or similar. make sure the points gap is at least 010" on each side and, ideally, not more than 015".

[Hughsie]

Thanks for reply. Found all of the above lol but I’ve not really touched the mag in several years. Cleaned both rings and replaced HT leads which I’ve realised was the main problem. so should be sparking like Zeus soon.

[CheeserBeezer]

The slip ring looks like it's seriously carbon tracked. That could easily be the main cause of the problem. p.s. your brushes are in the post!

[Hughsie]

Ok all. Thanks for the replies. Question:
I’ve cleaned the mag up nice. Points are about 012 on one side and 015 on the other. So pretty close but not exactly the same. Maybe a little wear.
I changed all the leads and caps etc and found a bad old lead so this has helped no end.
But I have a very intermittent cough or spit, it’s not all the time. And it’s sometimes when ticking over or occasionally when riding. It’s not terrible, but what could that be?
A couple of points, I am only running on one fuel tap, the other is blanked off due to thread damage (been like this for years before I bought it) I always keep it well topped up.
It starts easy, I don’t get kick backs so I am not totally sure it’s a timing issue, but could be I suppose. (I have a manual advance)
Could it be as I’m running on one tap I need to slightly increase the fuel level? I’ve not checked this yet but I’ve made a clear Perspex float cover to check heights.
Any kinda thoughts?
I’m running the recommended jets for this bike and I’ve cleaned the jets etc to check there are no blockages?
Wondered what the gut thoughts were, do they just do this ?
To be honest it’s running the best it ever has so I’m getting out and using it, but this feels like the last little hiccup I’d love to sort.
Maybe point gap in or out?
Ps it’s an alloy head A7 SS but it’s not an original SS.
I’m running champ plugs and I set the plug gap correct per this forum.
Appreciate any thoughts.

[berger]

worn carb slide , now i'm going to the open the bar today has been sht !!! rant over

[Hughsie]

Shouldn’t be. New carb 

[muskrat]

G'day Hughsie.
What fuel are you using?
Cheers

[Hughsie]

Hi.
I always use E5 super unleaded, ideally from esso down the road. Sometimes from the bp station.

[RDfella]

The comment re unequal points gap reminded me of a similar issue I had, albeit with greater difference.
Clearly the points assembly was not to blame as the same points arm supplies both cylinders. Tried another slip-ring - no difference.
Then, after much head scratching, found I could get parity by slightly tilting the cam housing on the mag body.
So, I made a note of which part needed reduction (around 3 or 4 thou) to get the cam housing square and carefully filed it.
Eureka - points gap equal. Obviously a better option would have been to mount the mag body on a suitable mandrel and turn the face square. But I don't have one and couldn't be ar*ed to make it. Neither did I trust mounting the mag on its mounting face, given the possibility of it being warped over the years.

[Rex]

I managed to decrease the points gap disparity by pushing (with my thumb) the points assy over while tightening the central screw.
Not perfect, but much better.

[groily]

Have to bear in mind in all of this that it is just as or more important to get the firing interval close as possible to 180:180°
Unequal points gaps of, say, a couple of thou, are less of a worry than a few degrees of error there (which doubles up on the crank if we try to measure at the mag). They often come as a pair, these problems, and the only way to get a handle on the the firing interval is to put a strobe on both sides and see. Static testing is OK up to a point - but isn't a reliable indicator of what might be happening at various different rpm.