Very poor spark on my 350 single

[DeanJordan]

Thanks for the replies guys ; I’m not so worried about long term reliability as I won’t be keeping it , for me it’s about rebuilding projects that are in bits or have been stood for years ,I just love it when thay start up after years, and I always spend more than I get back so it’s not for profit or to ride just a hobby iv only kept 2 of the 43 bikes iv had ,a bmw and a 77 kh 400 ; 2strok triple, iv only had a mag once before, it was on my t110 triton I built in 1982 , it let me down on a trip to Brighton, so not a big fan of mags

[MarkO]

The 350 quid I spent was for a full BTH mag overhaul by Peter de Kremer who has an excellent reputation and gives a guarantee. There are of course other folk. I'd tend to agree with Peter that as the root cause of failure with mine was unknown - as is the case with the vast majority of his customers - then it would be somewhat remiss not to check everything, fix where required and re-magnetise as a matter of course. Hence the cost - which given the time taken to do the work is not unreasonable. However, if you can be absolutely certain of the root cause - i.e. capacitor - then costs could come down somewhat.

Dean

Point taken, but I'd be reluctant to buy a mag bike converted to coil ignition if it still had the original dynamo, original regulator and without a new-ish battery. Mags are fine devices - nothing wrong with them. For sure they fail now and again but they can be revived to live another life equal in duration to the previous - unlike coils.

[nevhunter]

A magneto doesn't NEED a battery. That's the good thing about them. If a plug lead comes off you may damage the coil in it if there's no safety spark gap some where. Nev

[Brian_Walker]

I went with an exchange armature, the easycap didn't help much. The guy that did mine said to test if your mag is ok get an old plug and cut off the side electrode, the spark should jump from the center electrode to the side of the plug (about 5mm) if it wont do that at atmospheric pressure not much chance that will work under compression . The exchange armature had a new style solid state cap that wont be effected like the wax and paper ones. I also brought a $15 HAL sensor for small distributor on flea bay and 3D printed insulating washers an fabricated a aluminium holder for the HAL sensor. Quite a lot of work, then I had to buy a 6volt coil as well. It works ok and does allow manual advance and retard, the other benifit it does not require a huge boot to deliver a great spark. My mate reckons in wet weather I would be better off with the electronic one I built but the original one with the rewound armature is working fine so I'm not toutching it. (Also my hal one is a crappy body with lots of nicks and scratches.