Like Ian says, a well built magneto is very reliable. And a well built electronic ignition is also very reliable. Each will fail for different reasons. My personal view is that not all rebuilt magnetos are "well built", and stories about failures of expensive rebuilt mags abound.
To objectively compare the two options we need to take into account ALL rebuilt magnetos(bad and good) and compare that to the failure rate of all thorspark ignitions. I reckon if someone did the math, they would come out about even. Problem is, you will only find out if or when it fails. At that point, you will need to remove the dyno and the mag and mail your mag away to be re-re-built or re-re-re-built. Removing and installing a mag is a fair bit of work. Installing a Thorspark is piss-easy.
I have a Thorspark on 2 of my mag motorcycles including a WM20. They are easy to fit, allow you to dynamically time the spark with a strobe light, and for me at least, they start first kick every time. Power consumption is 1/4 amp so barely a trickle. If your Dyno is dodgy, not a good idea but if your battery and dyno are in reasonable shape, its all good. The argument that dynos are also unreliable is flawed. A failure of one component (dyno) is not a fault of the ignition, it is the rider not choosing to have a working dyno.
If you dyno fails while you are on the road, you need to be less than 8 hours drive from home because that is how long you will have before the battery runs flat. Hint, the ammeter will give you advance warning of this. The chance of a catastrophic failure of the ignition unit is as likely to happen as a mag failure, and in the case of a thorspark, it is not an electronic ignition, it is a points replacement. There is not much to fail. I guess the magnet could demagnetize... I thought about carrying a spare but there really is nothing obvious to fail. Just the pickup. There is no "black box", circuit board, soldered components etc. The pickups almost never fail.
I will now get things thrown at me from the mag-lover club and we will see passionate testimonials in support of mags. And, like my view, they are all opinions not really based on data. In the end it is a personal decision. Arguing the merits and shortcomings of either system is mostly based on personal choice rather than objective data (expecting more things thrown at me).
Did I mention setting the points and the timing will be a thing of the past. Also, timing does not wander around from stroke to stroke which makes for a better running bike.
I will now retreat to my shed and put on my tin foil hat, to live in blissful mag-free ignorance.
email (option): cas.vanderwoude@gmail.com
Hi
I have an old Lucas Rita system on my Triumph T110. It works really well.......until the battery runs low on charge.
I have MAGs on my other bikes (inc. the M20).
You just cannot beat a good MAG (no pun intended).
A reconditioned MAG is well worth the money and will last you a lifetime.
Regards
Pat
email (option): sacombsashtrees@hotmail.com
['The argument that dynos are also unreliable is flawed. A failure of one component (dyno) is not a fault of the ignition, it is the rider not choosing to have a working dyno.'...]
In the light of the above opinion I'll qualify my statement....After more than 45 years of riding (multiple) British bikes for my main form of transport (I don't drive a car) it has been my experience that the dynamo/regulator/battery charging system will fail far more frequently than the magneto will fail..
Consequently if you decide to use the dynamo/regulator etc. as the power source for an electronic ignition, or any other type of ignition, no matter how good that ignition is, a failure of the power source and thus the spark, will be more frequent than it would be if you used the self generating magneto...It's only about the reliability of the power source, not the ignition type...
I think I can say with certainty that I haven't chosen to not have a working dynamo (or regulator)...The dynamo based systems have failed for various reasons at different times, even short circuits in the wiring loom, battery failures etc. and not through 'choosing' some unspecified form of neglect that leads to a malfunction...
I would, and have considered using a self generating electronic ignition and don't hold any 'Luddite' views about the superiority of the magneto over everything else..I like to think I hold, and express, a more balanced view in these discussions...As in all things both systems have their strengths and weaknesses and for most who've tried both they will tend to favour most what has worked best for them...
However, as magneto development ended some time back and alternative systems are still being updated and improved they always warrant consideration as alternatives...Ian
email (option): ian@wright52.plus.com
I'm breaking my promise to myself not to post more than once in this thread.....
But ... regular readers will know that Ian's opinion is about a thousand times more valuable than my syphilitic rantings, because it is based on a much greater depth of experience. Nothing I ever say should be interpreted as a criticism of anything Ian says.
I'm just an enthusiastic amateur. Ian can rebuild an entire engine blindfolded with one hand, while at the same time solving the Times crossword puzzle. If I was going to rebuild a mag, I would ask Ian who to take it to.
In my defense, I live 3,000 miles from the closest Brit cycle mechanic and a bit further away from a good mag rebuilder. For me, working in isolation, the Thorspark is a logical option. Without advice from people like Ian, I'd be walking to work most days.
So, if you're new to this most wondrous forum, best advice I can give you is to ignore me and listen to Ian.:heart_eyes:
email (option): cas.vanderwoude@gmail.com
Thanks for your replies (more are welcome of course). I can't emphasize how much I appreciate having this website as a resource. Really.
Mark, I'm actually much more likely to visit relatives in the UK and Netherlands than I am to drive 9 hours to Ottawa but thanks anyway. We used to have three shops that repaired old brit bikes in my area but they've all closed.
I'm not new to Lucas, Smiths and BSA. I've owned a '74 Midget, a '65 BSA Lightning and still have a '54 Ariel 650 twin with the A10 engine. And as a small plane pilot I appreciate of the reliability of magnetos, even if all the electrics are toasted the engine will keep running at 4,000 ft. But this M20 I'm working on won't be my daily rider and I'm never going to be more than 40 mins from home on it let alone 8 hours. I have other bikes for that- a '67 Velo-Solex, '69 Honda Cub and a '05 Genuine Stella 2T. Ok, I'm not going 8 hours away on those either, heh.
Cas, thanks for the honest appraisal of your experience with Thorspark. I didn't want to rely solely on their own hype. It's great to get an independent customer's opinion.
Ian, I appreciate your input. If I had a good shop within an hour or two drive I'd take them the mag and wait.
[edit] Cas, I've been lurking here for a bit and Ian's expertise has already answered questions for me that others have asked. Like I said, it's wonderful to have such depth of knowledge here.
email (option): moatjon@aol.com