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General => Douglas Motorcycles - General Discussion => Topic started by: KiwiJohn on 06 Sep 2005 at 22:40

Title: Magneto enhancer?
Post by: KiwiJohn on 06 Sep 2005 at 22:40
Regular readers will know I have this 80 Plus that I spent years making look nice only to have it refuse to run but that is another story.   :x

Meanwhile while trying to check the magneto thoroughly I had to learn a little about such beasts and made an interesting discovery.

It is no secret that the spark is always weakest at the slowest speeds which includes starting.  The only way to overcome this is to kick the starter harder.

So, while I had the mag on the bench I tried a little circuit lashup which produces a burst of hot sparks when the points open no matter how slowly the mag is turned! :idea:

I think this is quite exciting expecially for those with difficulty giving a healthy kick and also for magnettos with weakened magnets,  which makes me wonder... Surely someone already markets what is a very simple device?
Title: Re: Magneto enhancer?
Post by: alwyn on 07 Sep 2005 at 01:43
Hi John,
I'm sure Doug will be interested in your 'exciting' discovery - he's away somewhere in Europe for a week or two but reckon he'll have something to add in due course - can't develop a human exciter too, can you :question:  :lol:
Alwyn
Global Mod
Title: Re: Magneto enhancer?
Post by: KiwiJohn on 07 Sep 2005 at 20:38
Having had a brain wave on the drive home yesterday I raced to my garage to try my 'simplified' version.

I took a jumper lead from the switch terminal of the horn and gingerly touched the other end to the magneto cut out terminal having first turned the mag until the points were open.

I was rewarded by a feeble 'beep' from the horn and a burst of hot sparks from one magneto plug lead!

So thats all there is to it folks!  The rapidly interrupting current through the coil of the horn is fed to the primary of the magneto and providing the points are open the high voltage spark is produced.

I AM ONLY TELLING YOU WHAT I DID!  I AM NOT SAYING YOU SHOULD DO THE SAME BUT IF YOU DO AND YOUR 50 YEAR OLD MAG KARKS IT IS NOT MY FAULT!

So far I have not tried starting the bike with this 'enhancement' and I dont really know if it will harm the magneto.  Meanwhile I have some ideas for simple circuits to take the place of the horn, perhaps I can even 'tune' it a bit by adding inductance and capacitance in the appropriate places.