HELP! Battery not charging, already changed stator, rectifier and new yuasa battery

[motorang]

I would not expect full charging voltage at idle. These alternators are using permanent magnets, and the charging is only rpm dependant.
On car alternators, they use electro magnets (coils) where the magnet power can be adjusted, and generally get a lot more voltage at lower revs.

So for weight considerations, most light bike alternators are using permanent magnets, and do any relevant charging when driving (due to higher revs = more power available).

Check your headlight between idle (1200 rpm?) and lets say 3500 rpm. It will start a bit dim, and get lighter when you slowly start revving the engine, so voltage will rise from e.g. 12.8 to 14 Volt which is when the regulator kicks in, and the brightness will not get bigger from then on.

As the amount of charging results from the voltage difference between battery idle voltage and alternator voltage, it will be less on idle than in the medium rev range and above.

For the alternator to fully charge at idle it would need to be a lot bigger (more copper, more iron, more magnets, bigger diameter).

Andy

[Miythras]

Well, still with the same problem, new stator, new R/R, new battery, new fuel pump, and I still can’t find the malfunction…
I’m considering tanking the bike to Yamaha…
They told me they had a WR also with electric issues, and that they’ve been trying to find out what happaned for 2 months… that got me scared…

[motorang]

Good luck. Did you do the check I suggested?

Andy