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Hey guys new to the site and just picked up a 79 cm185t. It currently has no spark and im gunna have to redo the electrical anyways. But my question is if im gojng to do a full overhall on the electrical what is the easiest way for me to convert the stock 6v system over too 12v for ease of a modern battery and bulbs.
 

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Several threads on this subject from past projects. Google "converting Honda CM185T to 12 volt" and you'll find them all.
 

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Hey @pwrballance

Jim’s right, of course. I dug around the forums here and maybe even posted my own story about converting a CMT185T to 12v... I can’t remember. Anyway, here’s what I did.

1. New rectifier
I got mine from SparckMoto. They’ll customize it for you to the exact length you want and include OEM style connectors. The mounting point on the CM185T has a tab that will need to flattened to make room for the new rectifier. That will be obvious once you see the factory mount point fabrication.

2. New lamps
Obviously, you’ll need to replace all the lamps with 12v rated lamps. Including the headlamp. Be careful with your plastics on the lamp housing. At ~40 years old they may be brittle if your bike wasn’t stored well over the years.

Headlamp:: https://www.amazon.com/dp/B01CFJ8GI6?ref_=pe_527950_33920290
Turn signals:: any 1156/BA15S/P21W lamp. I chose amber LEDs
Brake:: any 1157 or cross-compatible lamp

3. New headlamp housing
The OEM unit is an old-school sealed beam unit. Not only is it only rated for 6v but the light output is inadequate. I went with an Emgo replica Honda housing. The Emgo unit will need a hole added to match factory wiring loom for this bike. Other than that simple modification, the Emgo piece mounts right up to the factory mounting points.

4. New battery
I chose with a 12v Lithium Ion battery, also from SparckMoto. Extra bonus points for removing the maintenance of a lead-acid battery. Allows for deletion of the battery drain tube. The lithium battery is the single most expensive part in this project. The sealed, no maintenance battery is well worth it to me.

Additional considerations
I chose all LED lamp replacements, because LEDs. Not only do I like the like quality and brightness better. I figured it would be less draw across the whole system, increasing reliability. If you go this route, you’ll need an electronic blinker controller designed for LED applications. SparckMoto has a nice one.

All-in all, a pretty easy job. You can do this in a couple of hours.

When you’re done, don’t be shocked by the sound of the starter. It squeals a bit more than the 6v system did, but the starter is rated for 36v... at least that’s what’s stamped on the housing on my bike.

Doing it this way allows an easy OEM restore. No wires are cut, all original parts can be returned to the bike. When I sell the bike, the new buyer gets all the original parts in a box.

Hope this helps you, happy to chat more.

Marc
 

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Hey Marc,
Possibly you can do a complete write up including pictures of the entire process so this can be made into a sticky post in the Electrical section.
Might hold off on posting for a couple of days until the picture issue is handled, website migration has left pictures behind for now.
 

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Hey guys new to the site and just picked up a 79 cm185t. It currently has no spark and im gunna have to redo the electrical anyways. But my question is if im gojng to do a full overhall on the electrical what is the easiest way for me to convert the stock 6v system over too 12v for ease of a modern battery and bulbs.
Did you ever figure this out? I just picked up two of these and want to convert them both to 12v. Any suggestions would be greatly appreciated.
 
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