Re: 1988 Yamaha 130 no charging system output
Fishon, looking at the service manual there are several things you can do. First I would check the resistance of the lighting coils. They are a 3 phase star configuration which you are refering to as the stator (stator - meaning static - doesn't move compared to the rotor - the flywheel with the magnets which does rotate).<br /><br />Pull the 3 pin plug with green wires at the back of the motor. With your meter in resistance mode, check the resistance between each pin. It should only read a few ohms, all pins being the same. Sorry I don't know what the resistance is - it's not specified. If they all measure the same, then the coils should be ok.<br /><br />Next step would be to check the peak voltage produced. With the engine running at 1500rpm, you should get 35v peak. Your meter must be capable of reading and holding peak voltage. At 3500 rpm, you should be reading 85 volts. If both these tests are OK, then the charging coils are working.<br /><br />Next in the chain is the rectifier / regulator. Its job is to take the 3 phase Alternating Current produced by the 3 charging coils and convert to Direct Current 12 - 14 volts to charge the battery.<br /><br />The manual states to test the regulator the following way. With your meter set to diode test (should be symbol like ->|- ) put one probe on black and green there should be continuity. Then swap probes around green to black should be open circuit or infinity. Probe between black to red, should be continuity, swap around probes, should be infinity. Finally red to green, should be continuity, swap around infinity. You are basically confirming the diodes in the regulator are working.<br /><br />If this checks out ok, then the regulator should be OK. Only other links in the chain is the red wire from the regulator, the fuse, and bullet connectors, wire to the battery. I would carefully check these for corrosion. With everything hooked up and engine running, check the voltage at the fuse (may have to slip the probe down the side), the charging voltage should be around 13.8 - 14.2 volts. Check the black wire from the regulator is not corroded. It is possible for a cable to measure OK with the ohm meter but when under load, it's high resistance. I had this problem with the helm trim/tilt switch.<br /><br />The charging circuit is very simple and not much can go wrong with it. Take your time and study the circuit so you get a feel for how it works and what the tests are trying to diagnose.<br /><br />I'm only going off the manual and my electronics knowledge, so if anyone has additional real-life info to add , please feel free to help out.<br /><br />Good luck,<br />David