Thorspark Electronic Ignition

[groily]

Original post from mike667:

Hey Gang
 anybody have any experience on the thorspark electronic thingy's , always see them advertised on ebay-  they have them in 6V and use the lucas mag housing - seems like a good way to have benefit of  electronic ignition and retain looks of original -  thx! mike

Haven't got one of my own but have seen them on 2 twins (not BSAs) I know well and they have done fine for several years.
 
Yup, electronic should be better - the downside in my opinion is that a 6v dynamo with 60W to play with is a bit marginal. I have one classic 'electronic' (Boyer Bransden) twin in the shed - and the ignition is certainly impressive. But that has a 180W alternator and electronic regulator/rectifier, so there's power to spare. I only feel confident without a mag with 12v and an alternator with modern regulation. And the biggest battery that'll fit in the space.
For 290 bucks you could pretty much get a mag restored. You could certainly get all the bits for that money for home-assembly.
Really depends what you're going to do with the machine in terms of daylight/night riding, on your own or in a group, etc - and how far from home if the dynamo or regulator goes awol and leaves you with that flattening battery syndrome. If I really wanted electronic sparks and had to stay with a dynamo, I'd convert to 12v, get a 12v version of the kit or a similar one, a DVR2 regulator . . .  and the biggest battery, etc.

[beezalex]

I think using any battery-powered ignition with an E3L generator is asking to be stranded.  Get your mag properly rebuilt and it will outlive your charging system by a factor of at least four.  You can ride home with your lights dim, but you can't ride home without your ignition working.

Just my 2cents worth.

[mike667]

I think using any battery-powered ignition with an E3L generator is asking to be stranded.  Get your mag properly rebuilt and it will outlive your charging system by a factor of at least four.  You can ride home with your lights dim, but you can't ride home without your ignition working.

Just my 2cents worth.

thanks guys - good info - just got an extra mag, guess i'll just get it rebuilt rather than mess around

 Alex - my lights have been dim for years - why else would i have a shed full of 60-70 euro bikes in various states of decay....

[groily]

Reckon that's the best plan.
No idea obviously what your options are over there for getting the job done, but SRM sell most of the required bits, including armatures on an exchange basis (which not everyone will do), and I currently have another K2F with Dave Lindsley in the UK on behalf of a local friend for a full rebuild. There be others, as discussed in threads here from time to time (Sean Hawker springs to mind), but I hope there's the same expertise on hand a bit nearer home, where the dollar goes a lot further. Turn-round times for rebuilds run from about 4 to about 10 weeks this side of the water, with a stock 2-yr warranty. Exchange parts come by return post. Independent Ignition Supplies have all the small bits as well, but as someone else pointed out, the postal charge can be pricier than the bits.

[spyke]

Hi,
Although I havn't had experience myself with one of these what about one of those french 12 volt alternators (as advertised in Old Bike Mart) in the E3L shape.You could then have the best of three worlds ie. original look,12v elec ,electronic ignition,

Spyke

[beezalex]

The Alton alternator is nice and certainly will give you better lights and allow you to run electronic, but for the cost of an Alton and electronic ignition, you can get about three K2F's professionally rebuilt.

[Thorspark]

A discussion of Thorspark power draw.

I have read various comments on forums saying that the fitting of an electronic ignition to a 6 volt bike will leave you stranded.  We make the Thorspark electronic ignition, and beg (obviously) to differ.  The comments normally go on to recommend various 12 volt conversions and magneto re-conditioners.

The 12 volt Thorspark kit draws a maximum of 1/4amp, the 6 volt version a bit less.   This equates to a power draw of less than 3 watts for the 12 volt version, and just over 1 watt for the 6 volt.  This is not a large extra heavy load on the bike's electrics.

I have seen advise on various forums that if you do not upgrade your bike's charging to 12 volts, it will not be up to providing 1 watt of power for the electronic ignition.  This is self evidently rubbish.  It doesn't matter whether you have 6 or 12 volts, as long as you have a battery that isn't shagged out, and that actually charges as you drive along, then you will be fine.

If you use the Thorspark, and you develop a charging fault, with either 6 or 12 volt, you will still have several hours of running with your lights off, but yes, you will eventually get stranded when the battery goes flat, whichever voltage you have.  Obviously a working magneto has the advantage of being self powering, and also if you are running a bike like many of us used to, basically with no electrics, then that is the only way to do it.  These days, however, many of us have bikes that are more or less up to scratch, and lights that actually work. 

I run a 1956 Matchless G11 on 6 volts.  This is unrestored, still has the original six volt dynamo, which as far as I am aware hasn't been re-conditioned, and the Thorspark electronic ignition.  When I bought the bike it had a recently reconditioned magneto, which didn't work despite costing several hundred pounds, and the original Lucas voltage regulator, which seemed to work sometimes but not at others.  I fitted a solid state voltage regulator made by AO services and supplied by Draganfly motorcycles, which has transformed the electrics.  The lights, although not as bright as modern bikes, now work similarly, they dim very slightly on tickover, and go to full brightness the moment you rev above a tickover.  With the lights on, the ammeter is charging at 15 miles per hour in 4th gear.

Magnetos are an excellent piece of kit. However we offer a reasonably priced modern alternative, that has some practical advantages.

It doesn't matter if you have 6 or 12 volts, as long as you don't have a charging fault, then you will have not have a problem.

[muskrat]

Thanks for clearing that up Thorspark. I have been an advocate of elc ign for 20 years. I have Boyer on both my A's and love'm. When the dynamo spat the dummy on the cafe I could still get over 100 miles on a tiny 4 amp battery. I haven't had to adjust the timing on the '51 in 12 years. Last night with lights on high beam the amp guage was showing + at 40mph in top gear.
Cheers

[bsa-bill]

A welcome mail as far s I'm concerned, my maggie has been reconditioned but left me in some doubt as to it's capabilities recently in regard to providing a good enough spark to ignite 9.5 + 357 cam  compressed mixture.
So much so that I have moderated my projects specs to better reflect my own kicking capabilities as they are now compared to what they were seven years and 2 stone more ago.
I'm keeping Thorspark in mind for possible future mods

[Triton Thrasher]

sales talk.

Thanks, obviously.

[sparx]

I applaud Thorspark for producing a neat bit of kit, and don't doubt that the switching unit draws a negligible amount of current, but the main current draw is from the ignition coil which has to be fitted in conjunction with the switching unit surely ?
  Or is there something I don't understand here ?   

[MG]

Yep, good point. I guess you won't get any good sparks from 1Watt peak power.

[Thorspark]

The power quoted is for the whole kit, including the coil draw. 

If you are using a traditional set of points and a coil for ignition, the points are closed most of the time.  All the time they are closed, there is current running through the coil.  Most is wasted power, as it only takes a very short time for the magnetic fields the coil uses to produce the spark to build up.  After these fields build up, the current continues to run through the coil until the points open to make the spark. This current produces waste heat, so most older coils were full of oil to help cooling.  These points systems consume quite a bit of power, as you mentioned.

The Thorspark is a variable dwell system, ie the coil is only switched on for enough time to make the spark, most of the time it is "off".  Thus the power consumption is much lower.

The spark itself has almost no power, in fact most ignition systems are suppressed, that is they have a large resistor built in to the plug cap or HT lead, in order to limit the current in the spark. 

[bsa-bill]

Interesting - I'm coming round to this I think.
As my Rocket Gold Flash is not claiming any originality ( rather the reverse ) and still proving very difficult to start ( in fact at the moment it refuses to ) I'm thinking electronic is maybe the answer, first though I get My Flash MOT'd tomorrow, then I need to swap magneto and maybe even carb from it to the RGF as I know they work.
The Magneto that I had refurbished and on the RGF seems to proved a weak spark and not consistently (although you know my eyes !!) and the carb also might have something to do with it as after lots of kicking the plugs were not wet, so if I can get these two onto my Flash I'll get to see if they work and what's what, ( I know carb's jetted different but should fire up right/wrong)

Sorry went off at a tangent back to Thorspark.

There are as far as I know three or maybe four such systems, Thorspark, Pazon, Wassel and SRM , are any of these the same?
Thorspark as I understand it makes use of the A/R unit and can be fitted into the existing Maggie, can it at a later date be installed in a Billet Maggie replacement body?

Any comments welcome

[Alan @Ncl]

Hello Bill, Marcus and all you other Gurus who I note have already discussed Thorspark on this forum. 

I think I have now managed to look at most of the previous posts and it seems to me that this system has considerable attractions, briefly summarised as follows:
1  All of the usual advantages associated with electronic ignition generally: i.e. good starting-spark, reliability, durability, etc.
2  Easily fitted within existing magneto CB housing with minimum changes and authentic appearance.
3  Relatively easy and flexible timing adjustment (although may need a strobe light to set up which sounds potentially messy?).
4  Competitive price.
5  Low power consumption, relative to some competitors (Thorspark claim average 1/4 amp or 3 watts on a 12 volt system).  This is important giving our normal battery charging limitations.

Its this last point that particularly intrigues me as it seems a remarkable achievement.  I know they only turn on the power to the coil the instant before its needed but even if they can charge the coil in say 2 milli seconds (which is very fast) then at 6,000 rpm I estimate the current draw could still, when averaged, get higher than a quarter amp.  Does anyone know what coil resistance is used and what sort of rise time it has? There must also be some power loss in the actual electronics too (albeit small presumably, relative to the coil).

Another point worth a mention is this.  I saw someone selling a used Thorspark on ebay and going back to a mag because he said he had a midrange misfire.  Now I would not read too much into that, one way or another; might have been nothing to do with the Thorspark system.  But it did make me wonder what kind of experiences people were having with them.  Are there any new thoughts on any of this?

Alan