yamaha xs400rj

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mkemu80 · #1 Unread post by **mkemu80** » Sun Feb 12, 2006 4:11 pm

My yamaha xs400rj 1982, won't stay on once its jumped. I got the carbs rejetted, a new battery put in, and a new fuel petcock. The bike won't start unless its jumped but i charged the battery it is a good battery. Once I jump start the bike (with the car off) and take the jumper cables off the battery the bike shuts off. I think its the alternator, if it is how much should an alternator for a yamaha xs400rj 82' cost?

BuzZz · #2 Unread post by **BuzZz** » Sun Feb 12, 2006 7:52 pm

Your battery is not holding a charge and your not getting any output from your alternator. Could be the alt. itself or the voltage regulator or a broken wire..... something is stopping any juice from your charging system to your ignition system without another system(the boost vehicle) to support it.

kar_the_terrible · Mon Feb 13, 2006 4:11 pm

you can check the alterenator windings with a voltmeter, disconnect the battery, and with the engine off, you can unplug the alternator connectors and check the resistance of all the coils

it should be REALLY low in the neighbourhood of 2-3 ohms per winding. Also check the stator windings. if you get the right values, then you should check the regulator. it could be that youor alternator is just fine but the regulator is fried.

I have some manual pages for the 1982 model somehere in my apt. let me hunt around and see if I can find it.