New battery fitted maybe four months ago! bike hadnt been started in four months, but had the battery stored in cupboard in a warm place!, charged battery when it was new, and it was fine, went for a quick spin over the holidays, and seemed bike was draining the battery, had to ride home with no headlight! not the smartest thing but it was still daylight 2pm.
Stopped for 5mins, and DEAD!, wouldnt even crank the engine!, lucky enough to have two birds, give me a push!
down a one way street (the wrong way) and it fired! Grrreat!!

Got bike home disconnected battery and forgot about it until this weekend, had the battery on low charge, for 1 & half days, fully charged about 13.6V
Started bike this evening, and the voltage drops, as soon as u turn anything electrical on! ie, headlight, indicators horn. (did notice the indicators not flashing)

Is there anything I can check, just connected the volt metre onto the battery, anything else to try?

it might have been not charging the old battery too, as it died!! ie this new battery being fitted at the end of summer!

any hints welcome!

Try putting a volt meter on the battery then start the bike, the voltage should pickup. If the voltage drops then you know the charging system has a problem.

You should get about 14.5v across the battery terminals with the engine running.
Blip the throttle ... if it spikes to 15-16v the reg rec is duff.
If it goes lower and stayes lower then it's the alternator, google it and see you can get one, I think a 600R or T'Cat will work but you'll need to check the part numbers.

Check the wires haven't got hot and burnt it changes the resistance and can be a cause of futher heartache.

Check the battery cables are on tight and there's no crap stopping a good contact. Check the earth strap on the frame too.

I had a very similar problem with my TRX and it turned out the connection from the alternator to the reg/rec was dirty. A quick clean of the connections fixed the problem.

ok, cheers for the replys, did stick the volt metre on the battery, its dropping from 14 to about 12, inside 5 minutes of starting and holding about 3k revs.

Will check all wires especially alternator, at the weekend hopefully! Thanks again for the info, can the alternator be repaired, think it works with bushes, a bit like a electric drill? but will check all the wiring first

sportspromatt wrote:ok, cheers for the replys, did stick the volt metre on the battery, its dropping from 14 to about 12, inside 5 minutes of starting and holding about 3k revs.

Will check all wires especially alternator, at the weekend hopefully! Thanks again for the info, can the alternator be repaired, think it works with bushes, a bit like a electric drill? but will check all the wiring first

There are no points of contact in the alternator, are you maybe thinking of a dynamo? It sounds like the bike isn't charging and is running off the battery (ie using the power from the battery to charge the ignition whereas the generated power would usually charge the ignition and battery) which is why the voltage is dropping steadily over time.

Check the wiring first as it's the simplest fix, then work through the rest of the gubbins. Good luck!

If the wirings is ok then it will be the windings inside the alternator.

Got plenty of almost new generators and regulator rectifiers on the shelf if you need parts. Sounds like one or both of these has failed.

bike is failing again, checked all fuses, and wiring connector blocks, bike seems to be running off the battery power, as after a 1hr ride, with light on, it kills the battery, a quick push and it jump starts!

Tested this again today with fully charged new battery, bike starts volts are about 13v, and stays there! headlight is killing battery, head light on volts drop to about 11V. Is it a regulator or alternator? I had a major prob then, run the bike for about 5 mins and it wouldnt turn off!!!!, key, kill switch, nothing, hit the starter button a few times, and this killed it! talk about roll reversal? Maybe its a ignitiion prob!

Tried the other bike, with same battery. same model, only Jap spec, (headllight is on constant) volts are about 13.5, and doesnt drop with lights, hazards, horn, everything electrical on.

Was gonna try swapping the regulator, rectifier, tomorrow, then alternator.
Last year I stopped the bike and left the headlight ignition on! for about five mins, (not on purpose) when back to it and bike would turn over, this lead to the new battery, bike hasnt been right since!

It's the alternator