Honda ST70 - 6v to 12v conversion

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willmc
Posts: 10
Joined: Mon Sep 14, 2020 5:00 pm
Rides:: Honda ST70

Honda ST70 - 6v to 12v conversion

Post by willmc » Fri May 21, 2021 2:44 pm

Hello All,

I have a ST70 6v and want to convert to the 12v to gain the benefits of the greater electrical power from the 12v.

Has anyone done this? Is it as simple as changing the whole wiring and 12v battery? I assume not...

Any info would be great, thank you.

loadedtoad
Posts: 888
Joined: Fri Mar 04, 2016 11:01 pm
Rides:: C90 CBR600 PE175
Location: Derbyshire-Leicestershire Border

Re: Honda ST70 - 6v to 12v conversion

Post by loadedtoad » Fri May 21, 2021 8:37 pm

Never done it but
No you wouldn't have to change the loom as a 12 volt system would only draw half the current for the same load ,so the wires would actually be less stressed.
You would need to fit a Reg/Rec off a later 12 volt C90 and add a couple of wires to make it work.
12 Volt battery obviously
Change all the bulbs and the horn to 12 Volt versions.
The hardest bit i'm aware of is finding a 12 lighting/charging coil that fits the back plate as the 12v c90 coil is a bit larger.
You could always have the original rewound for 12 volt operation.

cozi70
Posts: 593
Joined: Tue Nov 20, 2012 1:16 am
Rides:: Z50,cf70,msx and an auld german 1200gs
Location: Belfast, Northern Ireland

Re: Honda ST70 - 6v to 12v conversion

Post by cozi70 » Sat May 22, 2021 9:11 am

loadedtoad wrote:
Fri May 21, 2021 8:37 pm

The hardest bit i'm aware of is finding a 12 lighting/charging coil that fits the back plate as the 12v c90 coil is a bit larger.
Shire bikes used to supply them but unfortunately stopped so if you can find a stator plate and flywheel from a jincheng (easy rider) monkey m50 or dax dx90 engine .
These are a 6v style with 12v electrics suitable for the honda long crank with previously had advance and retard at the points area.
Iirc you'll need a slightly bigger 12v flywheel cover also as the your original one is too shallow to clear the bigger flywheel.
Alternatively I've seen bits from Thailand and the states about conversion kits, Beatrice cycles or doctor atv (dratv).
With cg cells being a previous jincheng importers they might have parts available.

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