DT50MX electrics.....

Number One Son's DT50MX has been flattening its battery. I actually
tested the charging when I did it up, and it was charging as well as a
6v system can.

But it isn't now. Hmf. And when I turned on the headlight, it glowed
super-bright and then popped the filament.

Oh-*kay*. So the reg/rec is fecked.

Locate voltage regulator. No sign of a rectifier. And then I find,
tucked under the frame tube where I'd missed it, one of those universal
fuse holders with a red and a white wire going into it. And inside
is.... nothing! The wires are joined. Well, bodged together.

Undoing the wires and then tapping them together produces a clicking
noise. Not from any relay, but from inside the engine. Where the
alternator is. Whaaaatt?

Out with the Haynes BOL, and yes, there should be a separate rectifier
and regulator. And there ain't no rectifier. But the wires going to it
should be... yes, red and white.

I'm amazed it charged as long as it did. OK, so a new rectifier and a
new regulator (they're remarkably cheap for these 6v things) and
hopefully we have a fix....

Oh, and a new headlight bulb. In fact, I'll get a couple of spares too.

 

I'm amazed it worked at all; I guess it's a solid-state regulator
with some inherent rectification via the transistor(s)?

That was the problem I had with my Suzuki 100 -- the lighting
circuit was fed directly with AC from the stator coils. 6V circuit, but
about 20 VAC with no load; regulation was via the load from the headlight.
So, whenever the headlight blew, which was not infrequently, the surge in
voltage would take out the speedo bulb and the tail-light too. :-(

--
Ivan Reid, Electronic & Computer Engineering, ___ CMS Collaboration,
Brunel University. Ivan.Reid@[brunel.ac.uk|cern.ch] Room 40-1-B12, CERN
GSX600F, RG250WD "You Porsche. Me pass!" DoD #484 JKLO#003, 005
WP7# 3000 LC Unit #2368 (tinlc) UKMC#00009 BOTAFOT#16 UKRMMA#7 (Hon)
KotPT -- "for stupidity above and beyond the call of duty".

 

Who knows? New rectifier is about a tenner: regulator about £30.

Haven't looked at the speedo or tail lights yet.

As the bike had been used for riding around private land for a decade, I
suppose the previous owner wasn't bothered about things like rectifiers
and regulators, as all the lights had been removed. As you'll know, it's
flywheel magneto ignition. Er, I think.