Motorcycle Repair: 86 vulcan 750 charging, motorcycle battery, yellow wires

Question
QUESTION: if i boost the battery it starts.the 3 yellow from stator im getting 10.15-10.30 amps on each. the reg/rect is putting out whats going in.also the 3 yellow wires are getting hot.dont think thats good.if i shut it down and try again no go. need help

ANSWER: Hi Dave,

What voltage are you getting across the battery at idle? at 3000 RPM? at 4000 RPM?
Ideally, you want to get 12 volts at idle, then around 2500 RPM it should go up to 14-15 volts and stay steady at that for any higher RPM.

A bad regulator will not keep that 14-15 volts steady; it will allow the volts to increase above 14-15 volts and this causes the battery to get "cooked".

A bad alternator (stator) will give poor voltage and the battery will not charge.

Some other things to check:
- Take apart all the connectors, clean and re-connect.
- Look for wires that are old and possibly damaged. Wires that are hot, generally indicate resistance. Resistance does occur in old wires and wires with poor connection.
- How old is the battery? Sometimes its best to start with what is cheapest and easiest...replace the battery to rule it out as a possibility.

p.s. If you are boosting the battery from a car, make sure the car is turned off. Otherwise, boosting a motorcycle battery from a running car can cook the motorcycle battery.

---------- FOLLOW-UP ----------

QUESTION: on the battery im getting 12.4 at idol & 13.1 at 4000 rpm.to ck stator do i unplug 3 connections and ck voltage between any 2 or3.and should voltage be 50vac?

Answer
13.1 Volts at 4k RPM sounds a touch low. Either way, if you have a good battery that is charged, even if it gets no charge at all from the bike, then you should be able to run the bike for a bit before the battery completely dies and you should be able to re-start it in between.

Please have a look at this PDF, its the ElectroSport Industries Motorcycle Electrical System Fault Finding Flow Chart. Its quite extensive, but if you follow it from start to finish, you will fix your problem.

http://www.klrworld.com/pdfs/fault-finding-diagram.pdf