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I've been a Mechanic a long time and the more I learn the more I realize how little I know .

Yesterday was a case in point ~ I'd installed LED dash bulbs in my old Mercedes and they created a dead short, long story .
 

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CB125T, EX250 commuter, Ninja 250 racebike, CBR250R(MC19), VF500F, CBR600RR, VFR750F
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There's at least one wiring fault. I'm drawing diagram from your descriptions. Have you do some measurements to verify...
 

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Discussion Starter · #25 ·
There's at least one wiring fault. I'm drawing diagram from your descriptions. Have you do some measurements to verify...
I have run every possible test I know of. The only fault I thought I was getting was the ground test on the 3 Yellow wires coming from the Magneto/Stator (This diagram lists it as a magneto)
I managed to get a drawing from Red Fox Powersports, they were very helpful. The magneto goes to ground through the electric choke (Electronic throttle on diagram). I suppose that's why I'm getting continuity when I test each Yellow wire from the Magneto to ground. When I pull the stator off I'll have to test it to ground to itself.

Another thing that is confusing is why the lights and dash panel are turning on when I use a jumper between the + on the battery and the unlabeled wire (which is red on the bike) running out of the Rectifier that splits into 2 and goes into the Rectifier Bridge. I would think the diode circuits would prevent any reverse flow through the rectifier to ground....

BTW I never mention the overall condition. It's a 2018 scooter, it's unmolested and show room clean with low miles. Everything is still factory parts. I've done all the services.



Schematic Rectangle Font Parallel Engineering
 

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Nice diagrams ! .

? Is there a files place in this forum you can save them to and label what brand & model scooter they're for ? .

A Magneto is a simple alternating current producing device that uses permanent magnets instead of an energized rotor with slip rings .

All you needs do is : change the A/C current into D/C current via a full wave D/C bridge and some way to regulate the excess charge when the engine is sinning fast .

Zenier (? SP ?) diodes work well, they're a shunt but sometimes, like in vintage British Motocycles they go open circuit and allow unregulated current to invade the entire electrical system, why some older bikes have reputations for blowing the headlights out .

Older Honda Motos use the lead/acid battery to regulate the systems voltage, this is sort of like having a really BIG capacitor .

Lithium batteries don't do well in these simple charging systems that lack proper voltage regulation .

You scooter prolly has some minor fault you'll find in due time .
 

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Yeah, something's not right. Lights turning on by themselves is clue.
 
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Ah ;

Better the track down the problem I think .

If it has any relay, unplug them then test it , might be contacts fused closed or the spring failed ~ Chinese things fail a lot even when they're well designed .
 
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Discussion Starter · #30 ·
You guys are misunderstanding the lights. I have no light issue. It only happened when I bypass that bridged rectifier to take it out of the circuit for testing. I was doing that to see if I could get full VDC to the battery with a jumper wire. That rectifier evidently is the component which prevents the lights/ign from back feeding through the battery to ground. When everything is wired the way it should be there is no issue. I'm just unable to understand how taking the R/R red wire directly to the battery turns it all on. I would think the diodes in the R/R would stop the flow to ground.
 

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Lights are already grounded permanently. See left side of headlight bulb#1

What you are seeing is effects of two different circuits for power to lights.

1. Red battery output to ignition-switch to Black wire to lights. Somehow this circuit isn't working. Lights should turn ON when you turn key ON since power is coming directly from battery. Trace this circuit from battery through ignition-switch to lights to verify power is making it to headlight with key is ON. Something may be disconnected

2. another source of power to lights is output of regulator then rectifier-bridge to battery then lights. Not sure why bridge-rectifier is needed. It serves no purpose.

So it would appear that rectifier to rectifier-bridge to battery is working properly. I suspect whatever is preventing lights from turning ON with key ON is interfering with proper charging.
 

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On my scooter , 1 light comes on with key and ignition . Other lights come on when engine starts .... only 1 light is battery , others use altenaror ....,
 

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@Zip143 , On this particular scooter, turning ignition key ON will light up: headlamp, license-plate lamp, instrument lamp, taillight, and winkers if switch was flipped left/right.



1. Question about blue-section between battery-power and rectifier. Is it plugged in? This is usually "turn-on" signal to RR or voltage-sense line for it to adjust output based upon charge state of battery

2. in its current wiring-configuration, does it turn on all those lights if ignition-switch was turned to ON (battery-charger not connected)

3. what is battery voltage with everything OFF?
4. what is battery voltage when you turn key to ON?
5. what is battery voltage when you push START button?
 
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@Zip143 , Let's take a step back:

1. what exactly is functional problem here? Lights not turning on when key ON? Battery not charging?
 
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Danno ;

Interesting diagram in post #33, I think the "Electronic throttle" is in fact a shunt or zenier diode .

Pretty simple system there .
 

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Danno ;

Interesting diagram in post #33, I think the "Electronic throttle" is in fact a shunt or zenier diode .

Pretty simple system there .
So that acts as 1-phase shunt regulator.
 
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@Zip143 Here's configuration I came up with from your descriptions:



Note bridge-rectifier has only 2 diodes used. This functions as an OR gate between 2 input green wires. This configuration is typically used to isolate 2 inputs so they don't interfere with each other. Doesn't make any sense because 2 input green wires are from exact same source, so they can't be isolated anyway.

For example, on Hondas with 3-wire winker outputs, running lights and blinkers, you can actually use 2 diodes to isolate these inputs and drive single LED bulb. This prevents backfeeding of inputs and causing dash turn indicator to turn on full-time due to running light input. More detail here: DIY - Connect 2-wire winker-lights to 3-wire Honda harness

So in this case, using 1/2 of bridge-rectifier to isolate 2 identical inputs on those green wires that's split off from single red output of regulator makes no sense. Bypassing it will increase charging voltage by 0.35v due to 0.7v drop across single diode.
 
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Exactly .

Crude but as long as nothing breaks, very effective .

Of course, those old Brit bikes had the same thing and exploding headlights were a thing...
 

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The rectifier is only to ensure no AC current gets to the battery .

Headlight runs off AC current and is therefore much whiter & brighter .
 

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But didn't he already confirm that 1st rectifier already outputs 13.8vdc?
Lighting in this case is DC connected to battery.
 
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