Off the top my head, 13.5 Volts is on the low side of acceptable. Check the FSM and adjust the regulator.
You haven't mentioned what the ammeter reads. The ammeter shows how much the battery is charging or discharging. This is a very useful tool in diagnosing charging system issues.
so put a wire from alt to batt plus. With everything on i get now 13,5 volts. with lights etc on it´s travels from 12,6 to 13,5 (it starts at 12,6 and travels fast to 13,5) volts. lights are now rocksteady in every rpm.
all measurments with the multimeter were alright except of the ammeter. there i onloy get readings while wiggling around. so i guess ill have to bypass the ammeter ?
You definately have a loose connection. This needs to be fixed first.
If you're wiggling the wire then its likely something to do with the wire.
However its possible the connector or ammeter stud itself is loose. Depending on how the ammeter was constructed, on some, if itgot overheated and the plastic warped or melted, the internal connection to the shunt can get loose. So if you can feel some movement in the stud - that's a possibility.
If you put both ring terminals together and the connection still needs wiggling - then the problem is definately in the wires or wire terminals.
PLEASE disconnect the battery if taking either ring terminal off, but esp the red one from the battery.
Observe in the diagram those wires are always connected to the battery positive. They are hot at all times! Touch any bare copper portion to bare metal and the battery will discharge as much power as it can to ground.
