Well I recently purchased a 78 sportster and I have never worked on this bike ,I bought a Clymer repair book but the problem I have found is not in the book and our local repairman thinks Sportsters are not real Harleys ,Anyway the book only shows 2 wires going to the coil and I have 7 now this bike has a electronic Ign with a old style point coil ,To tell the truth Im scared to attempt to experment with the wires as I dont want to burn anything up ,If I posted pics of my wiring harness could someone possibly give me a hand ?? My email is charleykoal1@yahoo.com

 

I donot think that that you have old style point coil. I know in my manual hd saya that you can not switch coils you have to keep a coil for electronic ign to match

 

If your bike is stock it should have points and a coil. There should be a gray wire from the points to the coil, and a white one from the coil to the starter and engine stop switch.
With the electronic system there will 5 wires coming from the ignition module - 3 go to the tach - black, red, and green, an 2 go to the coil - blue and white. Like 98glider said, using the wrong coil can cook the points or the ignition module. The electronic coil will usually have "electronic advance" stamped on it, and if I remember right a points coil will usually measure around 5 ohms, and the electronic is around 3 ohms. This is measured across the plug wire sockets.

 

With that number of wires on the coil it sounds as if it is being used as a junction point. I'd guess that where the mass of wires connects you'll find it is 12VDC whenever the ignition is on. The side with the single wire probably goes to your electronic ignition module.

Do you know what ignition module you have? Many aftermarket systems are available. Some have provisions for an electronic tach, but one made for your bike might not as it originally had a mechanical tach.

 

Ok heres what I got First my coil has no markings except 12v no + or - my wires are I have 2 white wires one is a lighter guage and it goe to the engine block to my ignition the other white wire is hot when key is on ,2 blue wires one is light guage and it also goes to igntion on the engine the other blue is taped sise by side to a red wire going into the tach housing ,next i have 2 wires connected together a green and a brown when made hot seems to be for the generator and oil light/sensor,and last as I said thye red wire it is going with the blue wire to the tach a last note the light blue wire seems to be ground (- ) now if needed I can take pics but I hope I can get help from what I have given . charleykoal1@yahoo.com

 

it sounds like some one did some back street wiring on your bike. and that some one didnt know exactley what he was doing. when I bought my '75 iron head the guy handed me 2 packs of fuses and said that I might need them. after I dug into the wiring and saw all the patch in jobs I just stripped out all the wires and started over. you dont need the wiring loom to rewire the bike but if you want a stock ride you can purchase them if you want or you can just buy a number of different colored wires and do it your self if you feel up to it. As for that repair man tell him to F@# OFF and find somone who likes sportys and can work on them. Otherwise you will get reamed on anything you buy from him or just get bad advise from him. You will find that there is a very polarised view of sportsters in the motorcycle comunity. and you will need to develope a thick skin towards the negative side of it. feel free to pm me if you have questions if you decide to dive into the project on your own.

 

I suggest that you toss the Clylmer manual and go ahead and actually buy the proper HD manual for your bike. I know that they aren't cheap but it will get you back to original wiring diagram for your bike. Then you can start over with what you actually have. You know; you can't get somewhere unless you know where you are. This is true of wiring also, as far as the color codeing goes is anyones guess since it appears to be totally screwed anyway, one thing for sure there shouldn't be any hot taps off the coil when you have a perfectly good battery/ignition circuit. Something to think about is where is the fuse/breaker protection if it is juryrigged.?

 

Like I said before I can not find the module for my bike and mine is a 84 early with the gen and i suspect that somebody put points in the bobber and I hvae just bought it 9 months ago and she has been running pretty good I did however did purchase a hd manual and it did say that the coils are different if you have electronic ign. modual(different years different coils and ign moduals) and she would burn up.I Know I have to check into mine for the points and do see what they are set at and check the timing marks so I can set if I ever have to change the pick up and that is why I have everybody here to help me I know mine has been rewired because I have just the basics no horn no blinkers just headlite and brake liteThanks guys.

 

you must change out your coil to an electronic coil points coil will not work also no more than 3 wires go to the coil check your diagram on it or get areal harley shop manualit has a good sound diagram

 

Before you jump to replacing the coil make sure you really do have a 5-6 ohm coil. Use an ohm meter and if the coil measures about 3 ohms then you dont have to replace anything. before you measure the coil make sure you disconnect the wires on one side of the coil, this way you are not getting any feed back from the rest of the system.