Forum

[Adrian]

Both of my ASBO Bullets have the BT-H FM1R fitted. A restorer down in Dorset told me three years ago that these mags have no ventilation and can "sweat" internally when they get hot, but that the resulting condensation when they cool down can cause internal corrosion damage.



I didn't know if this was true or not, but I figured it wouldn't hurt to drill a small vent hole in the timing peg blanking screw via the screwdriver slot on ASBO12, and the mag is still fine, so I will do the same with ASBO14.



Keep us posted on this one.



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[Count Johnny]

Sooo...



There's still bags of compression; the needle is still attached to the slide; and the pushrods, rockers and valve springs all checked out; so we've either got a slipped pinion or an internal fault with the mag.



Given that it's the quickest option - and Slo Poke and I are off to Germany in two weeks time - I'm hoping that it's the pinion and will be giving Paul a call this morning.

[Revband]

Unfortunately these BTH mags do have a bit of a reputation for failure.

[Adrian]

Haven't actually heard that, though I did keep ASBO 12's contact breaker drive and Pazon Sure Fire "just in case"...



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[Mark M]

Yes, Adrian, see my earlier comment. This is not just hearsay, you can verify the story by searching for "Humbernut's" problems as posted.

REgards, Mark

[sofiaspin]

I had a BTH mag on my Velo Clubman and it worked perfectly. An old Velo pal was convinced it was witchcraft and could not see the spark. The spark is very strong, just difficult to see and if looking in sunlight, forget it. Sounds like it has not been set up properly. I am not aware of reliability problems and as you say, solid state, which has a lot going for it. Quality kit. Grove Motorcycles are the agents if I recall.

[Dennis C]

Yes indeed if you get a good one great.they do fail it would seem, yes humbernuts woes, I also have a friend who went through four failures before threatening legal action unless he got a refund, and yes he got one, personally I would not trust one on any of my bikes.

[Jamesy]

Recent problem similar symptoms caused by HT lead faulty.Spark was not a nice sharp blue constant but yellowish orange erratic flow.

[Count Johnny]

I've two posted lengthy diatribes on this, but the forum seems to have a timeout feature.



Just to clarify on one point. The BT-H has been fitted to Slo Poke for two years and has been jolly lovely in that time.

[Adrian]

Mark M,



point taken, no-one's beyond letting a substandard piece of kit out of the door, sadly, though despite the problem mentioned to me earlier I was previously unaware of large numbers of problems. I notice that some of their newer models now have external CDI boxes as well as external ignition coils, could this be a reaction to earlier failures?

Count Johnny,



Further to Jamsey's point, racing HT lead (thicker copper core, yellow and black PVC sleeve) is sometimes recommended for magneto use if that's not what you're already using, though I'm not sure the current (sorry!) lead would be failing as dramatically if it has been fine up until now. While we're in that part of the system though, how's your spark plug cap? Might be time for a new one (unsuppressed as per BT-H's instructions).



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