battery or charging system ??

[wsar10]

short of the long, does anybody have an "in depth" understanding of of the above system ? I am an electronics tech (10 years) and a hobbyist engineer.

issue: "no start"

theory or prognosis: was bad battery......


observation: I could bump start it, and start in normally with a jump (from my garden tractor), batt. was @7v not under load, The charging coils ohm out within spec also (.8ohm), with the machine running the voltage DID NOT increase at the batt........
BUT you can not always gauge a bad charging system based on this observation, If a batt. is to far gone your charging system voltage will sag due to increased current demand.

WITHOUT the batt. hooked up and the machine running I have NO VOLTAGE at the terminals (from charging system)....BUT again this may not be an indicator of a faulty charging system, most modern electronics (respectfully) have a "feedback circuit" that will adjust voltage within a non-linear voltage regulator based on load, therefore it could very well produce 0v without a load......

trying to find a battery now........

Any thoughts ?

 

[Beamesy7]

So your starter button does work when you supply enough power correct? It sounds to me like your on the right track, these starting systems do not like to work with out a decent fully charged battery. Speaking from past experience. I would buy a trugel mg12-bs for it or a ballistic battery, they are expensive but maintenance free and last years.

 

[wsar10]

Yep, everything works as it should (starting wise) with correct supply voltage.

 

[YAMAHAULER]

your battery should put out close to 12 volts with it not running and when it is running it should jump up to around 14 volts at the battery my guess is the battery is shot and the charging system in the stator is fried thus the reason when running the voltage at battery doesn't change but it could also be a bad voltage regulator(the finned box next to the cdi by tail light) you need to ohm the 3 white wires coming out of the stator they are the charging coil wires any combination of 2
87-2000 they should read between .7 - .86 ohm
2001 and up should read between .51 - .63

 

[YAMAHAULER]

when running and you give it gas do the lights flicker or dim down?

 

[wsar10]

As stated in my post.......The coils within the stator do checkout right under 1ohm. I didn't check the lights with the battery in the four wheeler...but when it is unhooked yes the lights dim with revs.

 

[YAMAHAULER]

then it's possibly the battery is junk and or the Voltage regulator is fried

 

[YAMAHAULER]

and the white wires need to be within those specs that I listed if they are below or above those specs or if the ohms jump around it's not working