750 k6 charging problems

[sticks]

hi can anybody give me some advice,i have a charging problem with my cb750 k6,with the lights on battery goes flat after about twenty mles,dont know if this the correct thing to do but i connected a voltmeter to the battery and it reads 12.4 volts without the lights on and down to 11.5 with them on,have tried adjusting the regulator,no difference,adjusted the points and core gap,still no change,could a rectifier be at fault,or have i got to go down the new generator route,not being an a electrical buff any help would be appreciated,it is really hard to find any secondhand parts,just mention i have just fitted a new battery.
thanks
Dave.

[SteveD CB500K0]

What is the voltage across the battery terminals with the engine running (>3000rpm)?

It should be about 14.5V. If not, your charging circuit has packed up.

Post back

Steve

[sticks]

hi mate
it is only reading about 12.4 volts across the battery with engine running,is it likely to be the generator? not easy to fing a good secondhand one.

[Yoshi823]

As an electronics engineer it would be all too easy for me to go into too much detail. So here is the best way to check alternators, rectifiers & regulators...

http://www.google.co.uk/search?client=firefox-a&rls=org.mozilla%3Aen-GB%3Aofficial&channel=s&hl=en&source=hp&q=alternator+outputs&meta=&btnG=Google+Search

http://www.google.co.uk/search?hl=en&client=firefox-a&hs=Phe&rls=org.mozilla%3Aen-GB%3Aofficial&channel=s&q=motorcycle+rectifiers&meta=&aq=f&aqi=&aql=&oq=&gs_rfai=

http://www.google.co.uk/search?hl=en&client=firefox-a&rls=org.mozilla%3Aen-GB%3Aofficial&channel=s&q=motorcycle+regulators&btnG=Search&meta=&aq=f&aqi=&aql=&oq=&gs_rfai=

If all else fails I know a guy who has diagnostic equipment which can test motorcycle ignition & power systems easily & quickly.

I have a good spare OEM rectifier for a 750 Honda as well as good spare windings. Unfortunately I don't have a spare regulator.

[sticks]

Hi mate thanks for the info,how much for the windings,and the rectifier.
thanks
Dave.
perhaps you can e.mail me thanks.

[Yoshi823]

PM sent...

[sticks]

Have been trying to sort out my charging problem,rectifier and regulator have checked out ok,have done a continuity test on the generator,i seem to have continuity between one of the three yellow wires to ground,which acording to the workshop manual indicates a fault,so i may have found the fault.
yoshi i accidently erased your e.mail adress,you said you might possibly have some windings,perhaps you could let me know.
Thanks
Dave.

[sticks]

Have just removed generator cover,and found the problem,the clamp that holds the wires,has worn through and caused meltdown,when i removed the clamp the three yellow wires just fell out,so on the hunt now for some more windings then should be back in buisness,yipee.

[Yoshi823]

I have three sets of windings that are for either the 750 or 550 Hondas, but I do not know which is which. The easiest way that I can ascertain which is which is for you to arrange to pop up & we can compare the old set with what I have...I am only in Bexleyheath.

I can also test the voltage regulator for you as I have a variable voltage power supply & we can reset yours to factory specification.

PM sent with a phone number.