Shouldn't it be able to run fine without the battery once started? Does this confirm an alternator issue?

Rotor should be locked to crankshaft by matching taper, you should need a puller to remove. Engine will not run without battery, the rect/reg will charge a battery but not run the engine on its own.

Alternator output voltage should be checked without the rect/reg connected, should get approx 50 V AC at 5000 rpm.

Right so I'm in the garage after work, and testing the alternator output.

After having to clean off the spark plugs because the engine wasn't starting I managed to get some voltage readings.

Had my dad hold the bike at 5K revs and I tested the three yellow wires of the reg/rec plug and got no readings from any of them (0 volts).

The left pin (red and yellow wire) was reading 12.4 volts and the right pin (green wire) wasn't reading anything either.

I'm guessing this means my alternator's fudged? Or is it something else?

Yellow wires are AC volts and you measure from one yellow wire to another yellow, what was your multimeter setting.

Red/yellow wire is battery voltage and green wire is earth therefore your readings for these wires is ok.

magg wrote:Yellow wires are AC volts and you measure from one yellow wire to another yellow, what was your multimeter setting.

Now here's where I've been an idiot. (should have payed more attention in my electronics class when I was at school)

Had the multimeter on DC volts and tested each yellow wire to earth like a muppet. Shall get back on it soon.

No problem, easy to forget when one small part of the electrics is AC.

Right so tested it properly this time.

Got about 42-44 volts between each of the yellow wires at around 5K revs.

edit.. replying to wrong post .. oops

The rec/reg plugs back in, but it doesn't click, it just kinda slides in then wont go any further.

I had taken readings off the battery running and not, they were both around 12 volts.

hardnutdvd wrote:edit.. replying to wrong post .. oops

haha oh well