coil location st70

this is my first post so please go easy on me! i have justy aquired a st70 (69 -72) it is currently fitted with a c90 lump but i have just splashed out on a st70 motor & carb to return her to the original spec. my question is where is the coil supposed to be fitted in the frame? Is there any reason why i cant use the coil from the c90 as it is a 6volt model or is the condensor an issue?
The bike has at the moment the coil fitted in the air filter housing but as i will be returning it back to how it should be it would be useful to see a picture or diagram. thanks for any potential help.

Im no expert but the ignition coil, is in the frame under the fuel tank.
i would replace the coil with the correct one, but guess that depends on what your wiring loom looks like.

hope this helps

thanks for the info...will have to investigate further.

It's very odd if the coil is indeed in the air filter.
How whould it be earthed?
You can use a 12v coil on a 6v engine, if that's your question.
If the C90 is the 12v version, they probably fitted a CDI and regulator, which can be in the air box filter. (Still very strange, but possible)
So make sure you're talking about the right parts, or the built will only become more complicated.
If you're in doubt, any pictures would help.

The coil is number 1, located between the engine and the fuel tank, fixed to a frame bracket. (For earthing purpose)
http://www.cmsnl.com/honda-st50-b-belgi ... t/F17.html

What no-one has said yet, is that the way the coil is mounted, its easier to take the motor out, and reach up into the frame to fit/replace the coil... unless you are VERY flexible, and have tiny hands. Then you still have to take the tank out and that can be fun...

the coil is most definately mounted in the air filter housing....which is distinctly lacking an air filter because that is a cone type mounted on the carb. it looks to me as if whoever fitted the c90 lump soon realised that there wasn't room for the carb to face to the rear (like a st70 should) because it would foul on the airbox, so they faced it forward and for some reason they have stuck the coil and condensor in the air box. i have put my multi meter on the c90 it is 100% 6volt.
to be continued........................ just had a look in the frame and i cant see any specific mounting points. if any one has a picture showing a coil in situ that would be a great help. i suppose it could go under the battery but there are no holes drilled to bolt to the frame. i have looked along the spine of the frame but all thats in there is the ignition switch and associated connectors.?