Motorcycle Repair: recharge system, battery engine, check battery

Question
Hi Jan..I just got a 1981 Suzuki tscc 1100..the bike runs fine but I noticed it had the wrong battery and the check battery light was on so I purchased a new battery..the light is still on.I took it for a night ride and the headlight is not bright enough so I tested voltage at the battery engine off is at 12 volts..running is at 12.6 I am not sure how to test the stator or regulator..can you please help me?? Thank you

Answer
If you bought the right battery for the bike, then the charging voltage may be too low, usually the voltage will be around 14 when the bike is revved.  Could be a problem with the regulator, or indeed the circuit.  I'm assuming all the other circuits are working well, so the ignition switch is OK.  Check that the fuses are OK, and make sure all the connections, especially ground connections, are clean and tight.

Good luck, Jan