Installing Thorspark ignition on my BSA A10 1956 GF

[Viking]

The magneto on my late fathers BSA A10 GF from 1956 gave up.

It produce a spark, but not strong enough to ignite modern lead free petrol with 5% bioethanol.
It became weaker and weaker. Changed pickup, breaker, wires etc. etc. but it is no longer useable.

I had two options:
#1 Sending it to the UK and get it proff. rebuild incl.  remagnetize, new armature, freight etc.
500-600£ easily spend  incl. Freight to and from the UK. And how long will it last, this time.
(rebuild 3 times since 1994)

Magnetos do not like to stand unused for year after year.

#2 fitting electronic ignition

So the Thorspark ignition kit looked handy…

It has now been installed on the bike, and works quid well…

Stabil idle, easy to start, and great throttle response.

Was it worth the installation ?
Yes, it takes time to installed, and there is snags on the way. But YES. Great value for the money.( cost 30 % of a total rebuild of the magneto )

The hardware is of high quality, with aero plane quality wires etc.

Slip ring removed ( not easy, it was stuck ) :
https://picasaweb.google.com/110323277286299979642/ProfilePhotos#6189063672160038834

Ignition unit fitted in the magneto:
https://picasaweb.google.com/110323277286299979642/ProfilePhotos#6189063682957419970

Finding TDC:
https://picasaweb.google.com/110323277286299979642/ProfilePhotos#6189913640166343154

Setting timing to 33°BTDC:
https://picasaweb.google.com/110323277286299979642/ProfilePhotos#6189063706789682114

Electronic ignition fitted.  Coil in the tool box
https://picasaweb.google.com/110323277286299979642/ProfilePhotos#6189913723300115394

[muskrat]

G'gay Viking.
Nice work mate. You'll love it, set and forget. Is it 6 or 12 volt? Did you use a strobe light to do the final timing adjustment with the motor running and degree wheel?
Now to see if the charging system is up to it. I went the whole hog and fitted a belt dynamo drive and DVR2 reg.
Cheers

[Viking]

The bike is fitted with a belt drive on the dynamo.  Kit mk#2 from SRM.
It is 6 volt. positive ground..

Fitted with a electronic regulator

Works well.

My expirence is that the charging system, dynamo and battery all works well i there if a bit of current use on the system constant..

Running with pilot and rear light all the time.

I will fit a LED headlamp bulb and LED rear light to compensate for the power used by the
Thorspark ignition unit.

Changing from 6 to 12 v ?  Not on this bike, I will keep the 6 volt.  Might change it on my SR..


I have made a little picture user guide. How to fit a Thorspark ignition unit on the BSA    Text is good, pictures is stronger communication.

 
 

[worntorn]

Looks to be a good solution to the ride out push home problem. I'm fitting an Easycap to my mag and if that doesn't do it will try the Thorspark.

Glen

[Viking]

Easycap looks good and it works if the condenser is the problems..

The are other issues with magnetos only an electronic kit solve:

#Timing differance between the two cylinders should be 180 deg, in the mag, via the slip ring, but the slipring is not that accurate.
# Ware on the contactors move the igniting timing.
# The advance timing moves with ware on the ATU
# Pick ups needs service, oil seal starts passing oil in to magneto, ect ect.
# Small sparks when starting. The mag demand a small pluck gap or it ware the mag down
# Difficult to start modern fuels with 5 % bioethanol
# Setting the timing correct with the mag is very time consuming and difficult.

The only huge benefit with a mag is: No need for power, battery and constant power supply.....

I love the idear of haveing a mag. Service and forget.  But this child of the 40's and 50's now has a more attractive sister. :-)

[Triton Thrasher]

Easycap looks good and it works if the condenser is the problems..

Have you used one?

The are other issues with magnetos only an electronic kit solve:

#Timing differance between the two cylinders should be 180 deg, in the mag, via the slip ring, but the slipring is not that accurate.

The slip ring has nothing to do with timing.  You mean the cam ring.

# Ware on the contactors move the igniting timing.

Have you used a magneto? contact breaker points (contactors?) and tufnol heel wear takes a bloody long time to affect anything. And is covered by a service routine of checking points gap.

# The advance timing moves with ware on the ATU

In theory!  Now you sound like someone who hasn't used a magneto with Lucas auto advance.

# Pick ups needs service,

Once again, hardly ever.

oil seal starts passing oil in to magneto,

Usually a sign of an engine problem.

ect ect.

Have a glass of water.

# Small sparks when starting.

One kick starting is good enough for me.

The mag demand a small pluck gap or it ware the mag down

Recommended gap is 18 thou, which is smaller than 25 thou. Does that cause you a problem (or should I say "would it, if you had a magneto?").

# Difficult to start modern fuels with 5 % bioethanol

Dubious.

# Setting the timing correct with the mag is very time consuming and difficult.

There's more to it, than setting most coil ignition timing. Could be time consuming and difficult for people who don't know what they're doing.

I love the idear of haveing a mag. Service and forget.  But this child of the 40's and 50's now has a more attractive sister. :-)

On an A10, a good magneto will serve you better than an electronic conversion, generally speaking.

[bsa-bill]

On an A10, a good magneto will serve you better than an electronic conversion, generally speaking.

Very generally speaking in my opinion - if a little truculent TT
 My 7:1 Flash is brilliant on it's magneto, I love it.
My other bike with 8:5 compression is a complete PITA with a magneto (refurbished magneto), try every way to get it to start and run reasonably, changed the magneto to the one on the Flash, no change, timed retimed, no change, on the occasions it did start it pinked on every slight hill or twist of the throttle, I spent months changing settings, cleaning slip ring, changing plugs (that's yet another story).
Fitted Pazon ignition - starts first time every time if the battery good (that's' the one downside of course, same as every modern vehicle on the road right) and runs perfect with no pinking)
yep I like the independence of a magneto but if they had been so much better than electronic why did bike manufacturers change

[muskrat]

Fair go TT. Vikings terminology for bits might not be correct but his English is understandable. I also think a mag is a PITA and will never (even a new one) be as accurate as electronic. A full mag rebuild costs twice as much as electronic and it's still an old mag needing maintenance.  Each to his own.
Cheers

[Triton Thrasher]

Hi BSAbill.

My manners? I'm not crazy about them myself, but I don't like to see advice which I think is spurious.

I've seen your sad story before, Bill and I have no idea what was wrong with your faster bike and the mag.

I use nominal 9:1 pistons in a T110,  but the ratio measures at 8:1.

I can see the theory of high compression preventing starting, but compression ratio isn't cranking pressure. A compression test shows 185 psi on my 650 and starting is just fine.

Why a magneto would cause pinking is beyond me too, but some electronic systems use a gradual advance curve.

Why did makers change? Modern car and bike original equipment ignition systems, with modern electrics, are better than magnetos and better than points and coil.
The trouble is, modern vehicle original equipment is not what you get when you buy a Boyer and really good charging systems are not easy to arrange on pre-unit BSAs (or dynamo-equipped Triumphs: I've tried!).
Your Pazon may be better than a Boyer and I'm glad to hear that it's working well. A recent Boyer may be better too, but I am a doubter until convinced. The onus is on them, not me. I get the impression that the Trispark fails in service far too often.

Does the Thorspark use the original Lucas auto advance?  That makes me wonder if they're even serious.

Edit- oh shit they use the magneto bearings too!

[Triton Thrasher]

Fair go TT. Vikings terminology for bits might not be correct but his English is understandable. I also think a mag is a PITA and will never (even a new one) be as accurate as electronic. A full mag rebuild costs twice as much as electronic and it's still an old mag needing maintenance.  Each to his own.
Cheers

I don't expect everyone to agree with me. If you can't find or afford a good magneto, you'll use something else.

My mag rebuild from Tony Cooper cost £140 7 years ago and has performed well.

I hadn't read Viking's previous post, showing that he has more experience than I assumed.

But anyone who thinks  the cam ring is the slip ring has serious gaps (>18 thou) in his garage expertise. What does he call the real slip ring?

[unclerob]

Just out of interest there is an electronic ignition system available that is independent of the charging system in the same way a magneto is....
 http://www.interspan-ignition.com/products
It has a built in battery pack and is charged by plugging it into the mains though I believe a lead is also available to connect it into the charging system if required.
Admittedly you only have a limited range with it but mine is on a bike with no other electrics at all so makes a very simple installation...trigger, kill switch and earth are the only wires.

[muskrat]

I ran the Boyer on my racer total loss from a tiny 12v sealed battery. Would do 6 races over a weekend without needing a charge.
Cheers
ps It's the same battery in it now and when she snapped the dynamo belt I still rode for over an hour before it quit.

[Viking]

The mag. on the GF bike has been rebuilded 3 times since 1993.
On time by a Company in Sheffield cost 290 £
lasted two years.
Next time 1996 SRM, new amature, re-magnetized, oil seal, bearings, cam ring ,  etc etc  approx 500 £

Rebuild again 2005, at a cost of 450 £

Beside that it had used pick up units ect..

Now it need to be re-magnetized again.
Sending it to the UK and waiting for months before they bother to rebuild again, sent me in a other direction: Electronic ignition....

See the same issues with my other bikes.
Lost magnetisme when standing for long time unused.

Mag. demand a lot of attenchen for few miles.
"Modern" fuel with high content of ethanol 5% , and now changing to 10% , demand a strong spark when starting.

There is a modern magneto that might last for years without issues:
http://www.bt-h.biz/k2f--lucas-replica-flange-magneto-13-p.asp

So telling that the old Lucas mag. is a wunder thing is pure "Gobshite"...

"Lucas inventer of the darkness and weak sparks :-) "

[Triton Thrasher]

The new Bt-H magnetos had a few failures. The makers claim it's sorted out. Who knows?

[Butch (cb)]

Yeah - usual arguments abound.

Had my mag refurbed around 12 years ago. Can't remember by who or how much, though I must still have the receipt on file somewhere. Had an initial issue with a dodgy out of 180 cam ring that was fixed with a Dremel. Only done around 3k miles since and adjusted the points just once in the time. Had it figured to outlast me.