Bolox

Changed the fuel filters and all seemed rosy in the garage as the
Triumph sat there idling nicely. Ran it up and down the road a few
times and then left it idling while I cleared the tools away and all
of a sudden back to back foring and cutting out. Starts more easily
now and the new filters are clear plastic so I can see they're not
clogged.

Flattish battery causing the Boyer Bransden to misbehave? The battery
certainly wasn't discharged and its relatively new. It's on charge
now and we'll see what transpires tomorrow.

For this evening, I'm pissed off and getting outside a few Leffes.

 

Thus spake AW () unto the assembled multitudes:

Have you got a short somewhere or ignition earthing out intermittently?

 

Possible. I'm going to check connections this evening.

 

Didn't find any loose connections, but charging the battery *seems* to
have got it running right, though the tick over seems a little lumpy...

 

does the ignition have a coil and if so are you getting full voltage at the
coil?

 

One would assume so, but maybe something's worked loose. I need to
get the tank off to have a look but as there was a power cut here last
night I didn't get the chance to get into the garage. Hoepfully I'll
be able to check it over during the weekend, though it's in the
history vehicle display in a little local fete thing tomorrow...

 

Yes, and dunno. Have to check over the weekend!

 

Which model of Triumph is it?

Oily

 

'69 500 Unit.

Basically a T100R. Bottom end is from a T100S.

This one: http://www.takkatakka.co.uk/bike3.html

 

It's a bit modern for me but, assuming it's got a zener diode on it, if this
becomes disconnected or loose (bad earth), then too high a voltage can cause
the same symptoms but the battery acts as a regulator and pulls the voltage
down, assuming the connections and the battery are good. It doesn't sound
like your battery is getting enough charge though, can you check the voltage
from the alternator (ac) and from the rectifier (dc)? It does definitely
sound like a loose connection though, as someone else has said.

Oily

 

Bad form I know, but I forgot to mention, check the voltage across the
battery while it is running. Is the voltage fluctuating, or is it steady
but too high or too low? Fluctuating could mean a loose connection, too
high faulty or disconnected zener, too low not charging properly, rectifier,
alternator connections? Etc,etc.

Oily

 

It's just had a new zenor as it was boiling the battery. I'm assuming
loose connections for the moment.

 

Cheerz.

 

You could tell the fete-thing organisers that you're going to stage a
SOB maintenance display...

 

I had silly problems once due to a slightly faulty switch on something. 12V
at the coil with the points OPEN, but less when the points were closed (for
points read "coil supply interruption device") - when the coil was drawing
current the resistance in the switch dropped the voltage. Took bloody ages
to diagnose - it'd run fine, but not start properly. 'course, cranking the
engine drops the battery voltage and then the coil circuit dropped it even
more...

 

Echo