So I'm currently sat in a nearby village where I get off the A1 on the ride home from work using a nice old lady's umbrella she gave me as she saw me from her house (it's pouring with rain) because the bikes battery has died.

It had a full charge yesterday on the charger after Cadwell and the charging system has been nothing but brilliant since I sorted it. So I'm at a loss as to whats gone wrong.

The nice lady has just brought me out a camping chair too, what a star.

As I came to the end of the slip road and slowed to stop at the junction the bike coughed and farted then cut out with my voltmeter telling me the battery was dead, as it is. Bike won't bump start either with just me pushing it struggling for grip in the wet so dads on his way in the van.

I'll go through the usual charging system checks later, but I think this might be a bit more difficult to work out

Loose plug from dropping it?

Possibly, I've left it in the garage charging for tonight and I've gone to the GF's to ignore it.

I'll have a look at it tomorrow night after work.

It was playing up the other day, voltmeter flashing red at me on the A1 then charging nicely again after turning off the low beam. Stupid thing.

I'm going to try and buy a car on Wednesday, so I'll have reliable (I hope) transport to work whilst I sort this. I was going to buy one in October anyway, but don't really want to.

You need to buy a Mille...they are pretty fast for a 33bhp bike dontcha know!

my bet on a loose earth on battery/frame?

maybe loose fueses too.

if its flashign red occasionally somethigns up >.<

start with full charging syste check and if its all ok start jiggling connectors while its running (get a MM on the battery to watch voltage) and keep an eye on your gague too, youll soon find it if tis a bad onnection.

Right, this bike puzzles me even more.

Battery voltages:

Off: 13.1

Idle: 14.2 and rose to 14.9 not going any higher

5K rpm: 14.8

Low beam idle: 12.1 and did not budge

High beam idle: 12.1 and a very very slow drop to 12.0 (would have gone further if I'd have left it)


I left the engine running and the multimeter on the battery and wiggled every single connection on the bike, from the main earths to the battery terminals and even the rear brake light switch and nothing happened, not a single thing.

I checked all the fuses too, and they're all in good condition tight in their sockets.

The only thing that could have been slightly suspect was an extremely slightly loose positive connection on the battery, literally a quarter of a turn of an allan key and it was rock solid.

My theory is:

It doesn't like rain
It doesn't like headlights on and high rpm at the same time for a good length of time
It's telling me off for dropping it at cadwell carpark after barely taking it on track.....
Or there's an intermittent short that is heat related (didn't even get the temp gauge into the 70).


Any ideas on how to test it further?

Just to give a rough idea of what the bikes electrics are like:

AGM motobatt battery
Large finned reg/rec
GSXR alternator
Complete new wiring for charging system, including Magg's wiring upgrade
Low beam relay fitted taking power directly from battery
LED rear light unit
LED angel eyes (that have pretty much all now blown)
Koso voltmeter and charging system monitor
Acument Tempest Cat 1.1 alarm fitted
Standard electrics and wiring everywhere else.
And an owner at his wits end with this bikes electrics (if you hadn't already guessed)

Id ditch the led stuff chances are theyve gotten damp and youve got yourself a short remember led terminals are close anf it would only require one low resistance short to dramatically drain the batterys output.

Hmm, it could be the angel eyes.

The rear LED unit is fully sealed and watertight so that shouldn't be a problem.

I'll unplug the angel eyes for now and see how they go. Shame though, because I quite like them.

I suggest that you check the alternator and rect/reg reg in case one phase has failed. This would help explain why you have sufficient output with headlights OFF but insufficient with the extra load when headlights ON. It takes very little power to run the engine on its own.

Disconnect the rect/reg and measure the resistance between the three yellow wires.

Then with multimeter in diode mode, red probe to each rect/reg yellow wire terminal in turn while the black probe is connected to -ve output terminal of rect/reg. Shoulde read 600ohms.

Reverse multimeter connections and repeat procedure, result should be open circuit, infinite resistance.

If it can't even keep the headlights going without the voltage dropping it's clearly not charging. Like others have said, check the alternator and reg/rec. A bad wire or connector on that notoriously crappy circuit would likely not show up without a load but once you try to draw some current through it, it would drop the voltage. In addition to checking the R/R itself, I'd check the connectors on the R/R, the alternator connector on the right side of the engine (3 yellow) and the master fuse connector. The charge current has to go through all 3 of these. If any of the wiring looks corroded, burnt, or otherwise suspect (or if the connector is getting hot when running), it's likely shot and should be replaced.