Guest Posted April 13, 2015 Posted April 13, 2015 Hello. I own a Honda CB50J from 1978. I have a few electrical problems with it. 1) The headlight keeps burning out. I have changed the bulb 4 times, the light works fine in neutral, but the second I put the bike in gear, the bulb burns out. 2) The battery is not charging. The voltage reads 6v with the bike off, and 3.5v with the bike on. So to me it seems like all the current, which was supposed to go to the battery, is going to the headlight instead, What advice could you guys give me? Quote
Stu Posted April 13, 2015 Posted April 13, 2015 first thing I would do is forget the bulb and fix the charging system first the bulb maybe going due to the charging fault Quote
Guest Posted April 13, 2015 Posted April 13, 2015 first thing I would do is forget the bulb and fix the charging system first the bulb maybe going due to the charging fault Do you have any idea what the problem could be?Everything else, except the headlight and battery charging works. Quote
Stu Posted April 13, 2015 Posted April 13, 2015 honestly no not knowing the bike the bike is a bit before my time I'm afraid but its a honda and they are known for their charging system failures I'm sure eastanglianbiker will have a clue he will reply when he see's this Quote
rennie Posted April 13, 2015 Posted April 13, 2015 6V system! that's a bit unusual nowadays!Is it a generator/alternator? or something different?Dynamo? Whatever it will have some sort of reg/rec!I'd be testing that first! Quote
Guest Posted April 13, 2015 Posted April 13, 2015 6V system! that's a bit unusual nowadays!Is it a generator/alternator? or something different?Dynamo? Whatever it will have some sort of reg/rec!I'd be testing that first! The power is created by a stator, but it seems to be alright. I'm suspecting the rectifier to be bad. Do you reckon this could be the problem, or something completely different? ☺ Quote
Stu Posted April 13, 2015 Posted April 13, 2015 hondas are well known for the reg/rec to gothey are easy to test Quote
Dav3y Posted April 14, 2015 Posted April 14, 2015 Dunno if you have a wiring diagram. The rectifier seems to comprise of a single diode/selenium rectifier. There isn't an awful lot that can go wrong there. stick a multimeter on it if you can to see if it conducts juice one way but not the other.EDIT:-Can't really see how putting the bike in gear could blow the headlight. I'm guessing you are talkin main and dipped beams ?Might want to double check all the connectors around the stator/ignition wiring all connect up properly as the neutral switch seems to be with those wires. Maybe someone pulled wires apart in the past and plugged them back together wrong ?Also worth pulling the diode/rectifier out of the circuit as it looks to me all that should do is stop the battery from charging but still enable the electric to work. I'm guessing the battery is good though and maintains its voltage under load ?http://www.motelek.net/schema/honda/cb50j_at_6V.png Quote
Guest Posted April 14, 2015 Posted April 14, 2015 Dunno if you have a wiring diagram. The rectifier seems to comprise of a single diode/selenium rectifier. There isn't an awful lot that can go wrong there. stick a multimeter on it if you can to see if it conducts juice one way but not the other.EDIT:-Can't really see how putting the bike in gear could blow the headlight. I'm guessing you are talkin main and dipped beams ?Might want to double check all the connectors around the stator/ignition wiring all connect up properly as the neutral switch seems to be with those wires. Maybe someone pulled wires apart in the past and plugged them back together wrong ?Also worth pulling the diode/rectifier out of the circuit as it looks to me all that should do is stop the battery from charging but still enable the electric to work. I'm guessing the battery is good though and maintains its voltage under load ?http://www.motelek.net/schema/honda/cb50j_at_6V.png Yes the rectifier is just a simple diode. I have the original assembly book and complete wiring diagram. The battery is brand new, and holds a charge well. I have inspected the wires, and all of them look fine. Think I might just order a new rectifier, to see if it solves the problem. ☺ Quote
Grumpy Old Git Posted April 14, 2015 Posted April 14, 2015 If the headlight bulb 'blows' when you put the bike in gear, then it MUST be due to a wiring fault in the neutral switch circuit - I would expect there is a short (in either a connector or the loom) which takes the two circuits (headlight and neutral) together.Measure the resistance from the headlight (any of the feed/return pins for dipped beam) and earth (ignition off) and see if it changes when you put the bike in gear (ignition off). repeat with ignition on, this time measuring the voltage (engine NOT running). This may help the diagnosis of the problem. Quote
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