Yamaha Spark 135 won't charge battery.

[canuckamuck]

I put a new battery in, it worked for a while and then it was back to kick starting it. Like before the change. I don't want to take it to the city because that is an hour drive. I just want to know what to fix so I can go get the part. How do these little bikes generate a charge? is it a magneto, alternator, generator? I should know, but I never had a bike that wouldn't charge the battery if the battery was good. 

I took it a local, he doesn't understand, he said he would charge the battery. I told him that was pointless because I can kickstart it and drive it to charge the battery if I wanted, but the battery won't charge as I already said. He knows better than me, of course, so he is charging it for me, lol.

[jackdd]

I once had this problem with a bike (not a Spark though), in my case it was the "voltage regulator" (no idea if that is the correct name), looked about like this:

After the shop exchanged it the problem was fixed.

It could of course also be something as simple as a cable which lost connection.

[canthai55]

Most bikes generate power thru coils fixed onto a plate on the end of the crankshaft. Or one big Stator coil that incorporates everything.

May be one coil for lights, one for ignition, one for charging battery.

Battery charging coil can generate either DC or AC. If AC there is a rectifier to change AC to DC that the bike requires to charge the battery

Use a multimeter - find out if 13.5 - 14.5 V DC is getting to the battery when running.

If not, could be a broken wire, bad rectifier, or the charging coil is shot.

As in all trouble shooting, KISS principle applies - Keep It Simple Stupid.

Eliminate the obvious before diving into expensive replacement parts

Old school and new school pics below

 

 

Edited February 11, 2021 by canthai55

[teacherclaire]

Some companies sell da_n old batteries and batteries can die after  a day, a week, or ten years.

 

    Use a voltmeter and check the voltage at the battery when bike is off. If the voltage is below 10/5 volt, charge it and then start the engine and see how many volts get to the battery from the regulator/ rectifier.

 

          You should have at least 12.8 to 13.4 volts.

 

       Also check the Cable connectors, clean them, the plus and minus at the battery, the minus that goes to the frame/engine.

 

Next would be to check the rectifier. If the regulator is bad, it's either too low voltage, or too high, mostly too low.

 

           If the rectifier is good, then you might have to change the coil. You should have three windings and none of them should have continuity to minus. These three wires go from the alternator to the rectifier. 

 

       Here's some reading: https://www.nadaguides.com/Motorcycles/shopping-guides/how-to-know-if-regulator-rectifier-is-bad

 

        

[teacherclaire]

5 minutes ago, canthai55 said:

Most bikes generate power thru coils fixed onto a plate on the end of the crankshaft. Or one big Stator coil that incorporates everything.

May be one coil for lights, one for ignition, one for charging battery.

Battery charging coil can generate either DC or AC. If AC there is a rectifier to change AC to DC that the bike requires to charge the battery

Use a multimeter - find out if 13.5 - 14.5 V DC is getting to the battery when running.

If not, could be a broken wire, bad rectifier, or the charging coil is shot.

As in all trouble shooting, KISS principle applies - Keep It Simple Stupid.

Eliminate the obvious before diving into expensive replacement parts

Old school and new school pics below

 

stator.webp 117.99 kB · 0 downloads

Battery charging coil can generate either DC or AC. If AC there is a rectifier to change AC to DC that the bike requires to charge the battery

 

Don't all these systems usually produce AC? The rectifier then changes it into DC and regulates the voltage. More when the battery is empty less, when it's full. I'd first change the rectifier they go bad often.

 

  On our little Yamaha 1100 cc already five times. Cheap Chinese Cra=p it is. 

[teacherclaire]

15 minutes ago, jackdd said:

I once had this problem with a bike (not a Spark though), in my case it was the "voltage regulator" (no idea if that is the correct name), looked about like this:

After the shop exchanged it the problem was fixed.

It could of course also be something as simple as a cable which lost connection.

Often used is rectifier, but it's definitely a regulator, regulating the voltage./ So either, or. 

[cali4995]

a few things to mull over . as i've got a few of these old scooters and have run the gamut of probs with elec starters

 

1. yes get a cheap v.o.m. ( bigC 99฿)measure voltage at rest ~ 12 and

then when running should be ~14

 

2. with a 12v test lamp , remove neg cable and place in series , if glows, you've a parasitic drain( eng not running key off)

 

3. it's also easy to forget, if push button start switch is crusty, won't work either. also true of starter motor( worn brushes) and start relay

Edited February 11, 2021 by cali4995

[cali4995]

so , like other fellas said keep it basic. 1. is it charging 2. cables look snug & tidy. 3. no battery drain 4. batt cond okay or sufficient

 

and then, when you've eliminated simple stuff. move on to charging circuit w/test rectifier, stator field coils etc. but more likely something silly

 

Edited February 11, 2021 by cali4995

[cali4995]

i've just sent  project click on it's way with a very happy friend-girl recipient (gratis)deal ofthe month for her. me , not so much

 

anyway , back to project yamaha which exhibits all symptoms of your spark. if voltmeter readings are in correct range & no current drains. the rectifier/regulator and internal diodes should be good. are headlights bright? another clue . and part is approx 200฿. already got new battery

 

i've long suspected the starter motor of just plain being old& wornout. gotta inspect the brushes in that. probably 50฿ part. it's only money

Edited February 12, 2021 by cali4995