The BSA A7-A10 Forum

Technical => Lucas, Electrical, Ignition => Topic started by: Viking on 02.09. 2015 14:56

Title: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Viking on 02.09. 2015 14:56
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
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: muskrat on 02.09. 2015 20:51
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
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Viking on 03.09. 2015 12:30
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.

 
 
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: worntorn on 03.09. 2015 18:25
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
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Viking on 05.09. 2015 08:02
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. :-)
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Triton Thrasher on 05.09. 2015 08:57
Easycap looks good and it works if the condenser is the problems..

Have you used one?

Quote
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.


Quote
# 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.

Quote
# 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.


Quote
# Pick ups needs service,

Once again, hardly ever.

Quote
oil seal starts passing oil in to magneto,

Usually a sign of an engine problem.

Quote
ect ect.

Have a glass of water.

Quote
# Small sparks when starting.

One kick starting is good enough for me.


Quote
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?").


Quote
# Difficult to start modern fuels with 5 % bioethanol

Dubious.

Quote
# 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.


Quote

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.
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: bsa-bill on 05.09. 2015 09:55
Quote
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
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: muskrat on 05.09. 2015 10:27
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
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Triton Thrasher on 05.09. 2015 10:41
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!

Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Triton Thrasher on 05.09. 2015 10:48
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?
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: unclerob on 05.09. 2015 12:01
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.
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: muskrat on 05.09. 2015 12:16
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.
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Viking on 05.09. 2015 12:54
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 :-) "
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Triton Thrasher on 05.09. 2015 15:19
The new Bt-H magnetos had a few failures. The makers claim it's sorted out. Who knows?
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Butch (cb) on 05.09. 2015 18:00
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.
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: bsa-bill on 05.09. 2015 19:51
Quote
The mag. on the GF bike has been rebuilded 3 times since 1993.
On time by a Company in Sheffield cost 290 £

Now then, both my maggies were refurbished by a firm in Sheffield (not at the same time) Thing is both work well on he Flash but neither work well at all on the higher compression RGF, could it be that they are both happy with lower compression but not quite up to igniting Rockets.
Groilly kindly offered to put my maggie on his test rig some time ago, I should take up his offer soon.
I wont mention who the firm in Sheffield are (actually it runs in my mind that they no longer trade?) as there is one thing Groilly mentioned that I did not try and that is the clearance of the safety screws - could be relevant

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

Yep I get where your coming from. as for manners I have been told (buy SHMBO) my "WHAT" is close to a declaration of war, it's just the way it comes out really
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: beezermacc on 05.09. 2015 21:01
I see the old 'Mag v Electronic' argument has reared its ugly head again!
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: muskrat on 05.09. 2015 21:31
We love them (either) just the way we want them. I applaud anyone who has the expertise, time and patience to get the best out of a K2F.
 For me it's just flick the switch and go every time. It gives me time to fiddle with all the other stuff that needs fiddling.  *problem*
Cheers
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Viking on 05.09. 2015 21:36
I found that the mag. last longer if they are used on a regular basis.
Standing unused for some years is a killer...

Started the GF fitted with Thorspark today. First easy kick, no chok needed.
Fitted two new 6 volt sealed lead batteries on the bike. The bike can run for hours with out
charging.
We have another 61 SR , fitted with a Mag. That gave in 3 weeks ago...
I havde been surrounded by mag's giving up....  So it is time to move on

But my old SR with a RGS engine has a mag, and I am not changing it.

The pro and cons about mags was a hot "war" in the 50's , chilled down in the early 60's and as soon as the bikes got a propper generator "battery ignition" was king...

Mags pro: independend ignition, no need for a battery, the faster it spinnes the better and stronger a spark
Con: Hard to get equal timing on boath cylinders. Complex instrument needing specialist repair, hard to adjust the timing..

Battery sparks pro: Simpel system, strong starting spark, easy to adjust, easy to repair if faulty.
Con: Need a good power supply. Dynamo is not ideal for this....   The first battery ignition systems was not fantastic quality, used a distribitur, oh dear...

Don't get me wrong, I like the mag when they performing correct. The A10 is correct with it.
But some times you had to be practical..
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: beezermacc on 06.09. 2015 23:26
But my old SR with a RGS engine has a mag, and I am not changing it.

Why are you not changing it?
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Viking on 07.09. 2015 10:24
Why not change from mag to Thorspark on my SR with RGS tuned engine ?
Because it is working fine... ( as good as a mag can). This bike is used more frequently, and has not lost its magnetism.
As long as it´s working I keep it.

If the mag on the GF was working, I continued with the mag.

I like the idea about "independent" ignition.    "Battery is flat and dynamo packed in, the engine will keep running and get you home"

But sending the mag to England, getting it reconditioned for hundreds of pounds and with short life span, and no use. Waiting for months to get the mag back from rebuilding,  is not a sport I will participate in.    
I used the GF with the Thorspark ignition a lot this weekend.  Starting is at “treat” very easy, hot or cold. It has never been so easy to start with a mag. It has a quick throttle response and pulls with more torque at low revs.

What about advance/retard with the Thorspark unit ?

I use an automatic advance unit on the bike.(even with the RGS engine. I don’t fancy fiddling with manual advance. The automatic units, work well. Adjust better than I can do myself with continually changing rpm. etc.)
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Topdad on 07.09. 2015 11:45
Has Musky says it's down to the individual , I've always used a maggy and I'm quite happy. Like CB mine refurbed approx. 12-13 yrs ago by mr Lindsey, still going strong (touch wood ) I put her to bed around the end of October and so far over the last 12 yrs or so when I remove the covers shes never taken more than 3 kicks to fire up. I'm first to admit I don't ride as quickly as some do (50-60mph) ,but thats down to knowing my limitations not the bikes which runs really well with a good solid tickover and good response even 2 up. I particularly like being able to get home even if the battery has given up the ghost ,which back in the day they did frequently .
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: duTch on 07.09. 2015 12:19

 I had my maggie refurbed circa '95ish, used it a couple of times only, then it sat redundant from at least '98 until 2013, and has been running fine since then- use it most days generally starts first kick except when I get complacent, and lazy *bash*
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: chaterlea25 on 07.09. 2015 18:14
Hi All,
If  a magneto has been rebuilt properly and as importantly the correct capacitor (condenser) fitted
It should last almost indefinitely, with just routine servicing,
I have mags which were rebuilt 30 odd years ago and are still fine
With the introduction of modern insulating materials the windings should no longer detioriate with age
The old shellac insulating absorbed moisture
In recent times there have been problems with the quality of slip rings and pickups originating from "God knows where"
Old even NOS capacitors die because of age,
I have had to replace several capacitors on "rebuilt" mags as they had failed ! they were not fit for purpose in the first place *razz* *razz*
Some pattern points are equally crap!!!

My 2 cents worth
John










Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Viking on 07.09. 2015 20:21
I agree, should work.

They have all been rebuild by SRM.
Rewound and modern capacitor fitted, cam ring reground, new Lucas contact etc.

It gave a spark, a weak one, But it is too weak to ignite the fuel..

Did a ride on the bike today again.  Extreemly easy starting. No choke needed..
Did a run with full light for hours.. No problems...

Good old Lucas parts, same good old quality as Layland
http://youtu.be/b9ztUlve9jc

Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: muskrat on 07.09. 2015 21:07
I will put a word in for the K2F. I had one rebuilt by Peter Scott in Sydney about 30 years ago. It ran the plunger for about 10 years, it was giving trouble at the end. I bought a new Boyer for the racer and put the old Boyer on the plunger. Fast forward 20 years and I plucked the K2F out of the box. I set it up on the bench and fitted spark plugs. First spin with my fingers produced a nice spark. Then hooked it up to the drill and it was giving beautiful sparks. It was then that I noticed why it was giving me trouble all those years earlier. The shaft was bent. I must have installed the auto advance unit a bit scewiff (don't know how) and running it like that bent the shaft.  *bash*
Cheers
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: edboy on 07.09. 2015 21:55
started up the a10  yesterday with a rebuilt off the shelf magneto. it was rebuilt 20 years ago by the old boy whose surname was day living in slough so the magnetism argument i think is a red herring. however i had trouble starting it until i changed the automatic advance to a more worn one that was happier to return when bolted to the mag. i would be happy to fit thorostart as it looks a good product but consider the old bsa auto adv unit the weak link for mag or thorospark. luckily i have a few spare ones i will strip and rebuild .
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Viking on 08.09. 2015 08:15
Getting at spark out of a mag, is not hard.
Getting a spark that can perform correct under compression pressure and ignite gasoline correct is a harder matter.

I have had a heap of old mag from boat engines. They give a fine spark on the bench. Fitted to the engine they can´t perform..
Low compression is ok, high compression is much more difficult..

Can you remember the old type spark pluck tester, in garages  ?
After grit blasting the plucks, they were tested under pressure to see if they could perform.

So getting at spark form an old mag. In free nature, is not difficult.

The worst enemy of magnets is: Vibration and heat.

They are not exposed to that laying idle in the workshop…

http://www.vehicle-electrical-rewinds.co.uk/magneto-common-faults.html

A good article about magnetos:
http://www.realclassic.co.uk/techfiles/magneto0912.html


Last night I did a good long drive with the GF A10, fitted with Thorspark ignition.   ummm.   good strong pulling power from low down.  Easy starting and smouth running.

     
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Topdad on 08.09. 2015 10:15
Hi Viking,
     
         "    Last night I did a good long drive with the GF A10, fitted with Thorspark ignition.   ummm.   good strong pulling power from low down.  Easy starting and smouth running"

You descriping my maggy equipped GF ?? ,Bob
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: groily on 08.09. 2015 11:14
If people don't feel comfortable with mags, fair enough, no reason why everyone should, especially if they're happy with their charging system or inves tin a modern BTH independent spark generator.
But there is no reason at all why a decent mag won't fire a high compression engine. Yes, on methanol at 14:1 or something there could be some HT insulation issues maybe, but for anything we need they should be fine. I haven't noticed modern fuel making a jot or tittle's worth of difference on my own bikes.

All the weaknesses mentioned exist, of course they do, but so do the strengths. Firing intervals can be got right, ATDs can work, the guts can last for years and years. Magnetism doesn't just disappear on most post-war Lucas instruments and is extremely rarely the cause of failure.
Some of the electronic options don't address all the weaknesses, can introduce new possible points of failure and also steal your storage space.

It's all a question of where you feel happiest carrying the risk (and/or whether you want 'original' I suppose). I don't care about original myself very much, looking first for 'reliable' to support quite high mileages. For me, mag + dynamo + DVR2, or alternator + decent solid state regulator/rectifier + mag = 'reliable'. For others, 'reliable' may = Alton alternator/ good E3L and electronic sparks or Lucas alternator + coil etc etc.

What the hell - as long as we're out there on the road, doesn't really matter does it?
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: muskrat on 08.09. 2015 13:29
Spot on groily *yeah*
Cheers
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Viking on 08.09. 2015 17:50
So the new BHT mag. is as well build, as the build to budget, Lucas thing. Oh Dear

The history repeat it self :

http://youtu.be/LSYD4a3RzW4

Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Triton Thrasher on 08.09. 2015 18:12
So the new BHT mag. is as well build, as the build to budget, Lucas thing. Oh Dear

The history repeat it self :

http://youtu.be/LSYD4a3RzW4

I don't understand.
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: Viking on 08.10. 2015 08:26
A little update on the electronic Thorspark ignition:

The bike has been used regularly since early September, many times.
Work very fine., starts 1.st. kick and has returned a healthy bottom end torque.

The dynamo can easy feed the ignition. The bike is used with light on all the time, because of “local high way code”
Fitted new sealed GEL batteries, to ensure plenty of power.
An added benefit: The bike now has an “ignition key”, can´t be started by anyone on the road side.
Nice when running round town, shopping, driving with the dork for a walk.  ( dog is in the side car)..
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: shuswapkev on 09.12. 2015 10:23
I have installed a wassel ignition in my 1950 A10..the ignition works great...runs like a  new Honda...
but endless issues with charging I have a DVR2 ..and either over charging or not at all.....trying to use it at 12v..maybe that's the problem
with a 10amphr battery...I can do about 2 hours  with dynamo disconnected
I will be getting my magneto rewound...
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: metalflake11 on 09.12. 2015 13:58
I have installed a wassel ignition in my 1950 A10..the ignition works great...runs like a  new Honda...
but endless issues with charging I have a DVR2 ..and either over charging or not at all.....trying to use it at 12v..maybe that's the problem
with a 10amphr battery...I can do about 2 hours  with dynamo disconnected
I will be getting my magneto rewound...

Check the earth wire on the regulator, if it is not perfect it can cause this problem.
Do it soon because you only have a very limited time with a bad earth before it fries the thing.
Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: KiwiGF on 10.12. 2015 04:35
Thanks for posting the info on fitting the thorspark Viking....

This post adds to the electronic v Lucas oem debate.....I have a electronic Bth on my A10 (works great after a faff timing it) and a rewound mag on my b31....a foot in both camps  *smiley4*

http://www.a7a10.net/forum/index.php?topic=6464.30

Title: Re: Installing Thorspark ignition on my BSA A10 1956 GF
Post by: orabanda on 10.12. 2015 05:38
The BTH on my Super Rocket has never let me down; very responsive engine, starts first kick hot or cold (and a FAST rider).

I also have just built a Thorspark ignition into the magneto of a 1938 Square Four; yet to run.

Richard