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Louie, Technician
Category: Motorcycle
Satisfied Customers: 12163
Experience:  25+ yrs. experience
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1974 Honda XL250 how can converter from 6 to 12 volts the

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1974 Honda XL250
how can converter from 6 to 12 volts the complete electrical system, just to let you now I dot this conversion in automobile
(Volkswagen) but to be honest, I don,t have any idea how to due in motorcycle specially which specific electrical parts I need to replace and where I can buy, I now need to replace bulb,, but what else?? and the at more specific is highly appreciate,, thank you in advance for any help.

My name is ***** ***** I am a professional here at Just Answer. I noticed that your question had not received a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.My info is somewhat limited on your model here but I had seen no one else has responded and would like to see if I can help here.If at any time you feel that I cannot help with this please let me know.

I see no one has posted any help with this here.In some cases this can be due to the info you may be looking for may be difficult to obtain or the correct person that can help may not be online.

In some cases this info may be difficult to obtain and may need obtained from a dealer or repair center.Usually they can tell you what parts or retro fits are needed to make this work for you here.If this was already attempted or is not an option for you let me know.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service,your 5 star rating is appreciated.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 9 months ago.
I still need help, if you found any information I going appreciate.

I will open your question up for others here to see if someone else can assist further on this as there may be others here that may have more info on what to check or do with this issue.I hope you can get this resolved with ease.No need to reply to my last post here unless it is a last resort as it will keep your question locked to me and others will not be able to view it.If you feel you want to continue to work with me on this feel free to reply at any time but keep in mind in some cases it can be difficult to fully diagnose or help repair this without seeing your vehicle.

Thanks Pete

Hello, besides bulbs you will need

1. Stator

2. Rectifier/regulator

3. Ignition coil

4. Battery

You'll have to check electric motor shops to see if one can rewind the stator as an off the shelf solution does not exist. There are universal regulator kits on ebay that can be adapted as well as coils. It's going to be a bit of an undertaking as you'll be piecing it together so to speak since no one makes a kit to do this.

Customer: replied 9 months ago.
Hello Mr. kwiggins29059,, thank you for your help, but I have a few question relate whit your answer,,
1) Stator,, mind A.C Generator?? (because I don't find nothing calling Stator in the electrical diagram)
2) Ignition coil,,is operate by A/C voltage or I wrong?? (I mention that because is what I think I see in the electrical diagram) if that the case,, still need to replace??
I according whit you to replace Rectifier,regulator,battery and bulbs obviously, but do you think I have a chance the A/C generator create enough voltage to make the 12 volts D/C I need to keep charge the 12 volts battery.
please by patient whit me, thank you again.

Good morning, I think we just have a differene in terms due to our geographical location. What I call a stator is the AC generator.

The stator produces AC voltage that is changed to DC voltage by the rectifier/regulator assembly.

The ignition coil should be operating on DC voltage.

usually AC generators for 6 v dc do not produce enough AC voltage, you could try the 12v reegulator and see how it does but usually they need more winding on the ac generator to produce the voltage.

Let me know how I may help more

Customer: replied 9 months ago.
do you have access to electrical diagram? my diagram say: ( A.C IGNITION COIL ) what's (A.C) mind?? can you double check if the ignition coil operate whit D/C,, and please confirm me, thank you.
Customer: replied 9 months ago.
hello,, do you have any answer for my??

Hi, I’m Louie. Sorry you had to wait awhile but I’ll do my best to help.

Initially , please click HERE. This is the diagram I have for the Honda XL250. Should your diagram be different, please post back with your copy. Click HERE.

From there we can work on the possible conversion with a common reference.

Customer: replied 9 months ago.
is exactly the same diagram I have, Mr Louie, and thank you in advance for your interest in help me out whit this.

The electrical system based on this diagram is composed of the three (3) sub-systems:

  • ignition;
  • headlight;
  • running.

While the latter 2; headlight and running can be lumped together and can be converted to 12V, the ignition would be relatively difficult thus challenging.

Please note that the contact breaker (points) is used to physically switch on/off power to the ignition coil is mechanical. This switching action results to the ignition coil to induce a high voltage to its secondary thus producing spark.

While theoretically possible to convert the ignition system to 12V/CDI, it would very challenging primarily due to parts availability particularly the magneto/rotor or more particularly the metal tab attached to it, the pulser (pickup) coil and its mounting plate as well as exciter coil to charge the CDI's capacitor. Equally difficult to configure for the spark timing.

On the otherhand, it would be doable to convert the battery, headlight, all other light and running system to 12V.

Please post back should you wish to proceed and/or should additional information be needed.

Customer: replied 9 months ago.
sure,, I wan a proceed, let me now how.

Including the ignition?

Or just the lights and other electrical + battery?

Customer: replied 9 months ago.
sorry Mr. Louie,, in your experience,, what you recommended??

Based on experience; just the lights and other electrical + battery. Modifying the ignition was painfully doable BUT, configuring the spark timing was a nightmare.

Customer: replied 9 months ago.
OK. tell me how please.

To have a common reference, please post back with clear closeup pictures of the alternator coils. Click HERE.

Customer: replied 9 months ago.
OK. Mr Louie, I send you the pictures this afternoon, please be patient whit my, thank you.

Yes please; when able.

Customer: replied 8 months ago.
hello Mr. Louie, can you please check this pictures

These do not appear to be the alternator coils.

The alternator / magneto coils would look something like the image shown HERE.

Customer: replied 8 months ago.
I see, sorry my understand Mr. Louie, the alternator coil still in the shell.
" how complicate is to pull out?? can you give me idea please, thank you.

Please click HERE. The pictures would provide insight.

Customer: replied 8 months ago.
thank you Mr. Louie, I going to pull out Friday afternoon. I replay you back.

Yes please; Friday or when able.

Customer: replied 8 months ago.
hello Mr Louie I have this pics, let me now is OK.

Appreciate the pictures.

Please identify the different wires (colors). These would be:

  • black wire with white tube - ignition;
  • yellow & pink wires to the rectifier for battery charging;
  • white wire with yellow tube - headlight supply.

Also, locate these parts:

  • regulator;
  • resistor;
  • and of course the rectifier.

The basic idea would be:

  • leave the ignition winding black wire with white tube as-is;
  • rewind the charging coil and headlight coil for 12V operation ;
  • remove the 6V rectifier;
  • replace the regulator with a combo rectifier-regulator combo;
  • remove the resistor;
  • replace all the bulbs, the battery and the horn with 12V equivalent.

Also consider LED types of bulbs if of interest.

Customer: replied 8 months ago.
Hello Mr. Louie, I have a question, how came the timing change if we modified from 6 to 12 volts, I dot a conversion in auto (Volkswagen) and never change my ignition time,,, why lost the timing in motorcycle? how complicate is to converter ignition too to 12 volts?
Customer: replied 8 months ago.
can you please recommended which rectifier-regulator combo I can use in this motorcycle, thank you again.

As posted above; "...possible to convert the ignition system to 12V/CDI, it would very challenging primarily due to parts availability particularly the magneto/rotor or more particularly the metal tab attached to it, the pulser (pickup) coil and its mounting plate as well as exciter coil to charge the CDI's capacitor. Equally difficult to configure for the spark timing...."

Thus the timing originally was based on a contact point opening. On the other hand, a CDI would be based on a pulse from the pickup coil. Additionally, a CDI system would need another coil whose function is to charge the built-in capacitor in the CDI.

On cars that still use breaker/contact points, there are products such as from Accel or Mallory or MSD that can add a transistorized ignition system. However, it is not CDI. Something like the operations as illustrated HERE. The challenge with this approach is getting a small ignition kit that would work with a single cylinder engine.

A ideal rectifier/regulator that can used with 12V rewound charging coil and headlight coil would be from a Chinese ATV/scooter that has 4-wire/pin connector. With most versions, their wire colors would be:

  • red to 12V battery's + terminal;
  • green to ground and battery's - terminal;
  • white or pink to charging coil; and
  • yellow to headlight coil (interchangeable).
Louie, Technician
Category: Motorcycle
Satisfied Customers: 12163
Experience: 25+ yrs. experience
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