SL 100 no spark.

Hi guys

My brother bought a property and hidden in the shed was an old Honda SL 100. It is a bit of a basket case, but looks reasonably complete and had been running before being parked in the shed. It was covered in years of crap but I thought it could be saved.

Now from reading all over the forums, I have replaced the battery, hard wired the kill switch and checked the points. All look pretty good.

But I still have no spark. I am thinking coil but have no idea how to test it. I really do not want to spend much money getting it going as it might not even go at all. It might be totally stuffed which is why it was left in the shed.

Any ideas on where to start looking now??


I would like to see ya get that going so...

... could be a list of things:



Ignition switch



You can get a very inexpensive electric tester from Harbor Freight to trace out the connections.

First see if the power from the battery to the ignition switch.

with the key on ( if it has one ) and the kill switch set to run, I think those got the power for the points from the battery. with the points closed, see if you can get a spark out of the ponts by opening and closing them with a screwdriver. If nothing is there your not getting power to the points. Usually if the condenser goes you will blow the points apart from too much voltage, of course if it's 6 volt I don't know if thats a possibility. Non the less, that would be the first thing, check power at kill ignition, to the coil and at the points. No power no sparky

thanks guys.

I am picking up a tester from a mate tomorrow. So I will see what I can find.

I would love to get it running but do not want to spend too much cash when I could just go buy something that is running.

I still have the ignition switch, but have hard wired the kill switch as it was a bit loose.

This thing is way more technical than the old 2 strokes that I used to get around on. But hopefully I can work through it and get it running.

thanks again.

I think when the ignition was on (when it had one) you had power to the points, so I'm guessing your kill switch is of the off/on type and not just a button.

So get your meter and start at the battery side of the switch and just keep working your way back till you get to the points, if no power, you may need a fuse,or a coil, maybe a condenser but I doubt it.

These little bikes are a kick to play around on, I had a friend with one when we were kids, and he could ride that thing all day on the back tire, very predictable, fun little toy.

Ok... I have my meter and I am testing away.

I have power at the key switch so I am goo to go there.

Can not seem to get the points to 'spark'. So I am thinking coil.

I have power to the coil and to the points.

Is there any way to test the coil? if so how? I do not want to buy another one if I do not have to.

Thanks for all your help guys.

OK wait a minute..... you have power to the coil..good, you have power to the points?, you have power to the terminal on the points that the coil wire is attached to?, If you do, you need to check if you have power on the face(the contact) of the points arm (the arm that is moved by the cam) with the points open, if you don't, file or emery paper the contact face and try again. If you do have power on the contact face of that arm, switch your meter to ohms and see if you get a zero reading beteween the plate the points bolt to and the non-moving contact, do this test with points open also. If no continuity (zero reading) file or emery that face. You may just have a carbon build up problem on the points. With power to the points, and them closed, you should get a spark if you open and close them with a screwdriver or anything just work the arm open and closed, even your finger if you can get it in there.

Another way to check points is with a small light bulb, like a taillight, put a wire on the body, tape it up, put a wire on the bottom pin, tape it up, with the key on and points closed, put one wire on the points terminal and one wire to ground, the light should be off, when you open the points the light should come on, if this test works your points are good. Now you can check for spark at the plug if yes your good, if no it's coil time, but check points first.

new coil is about 75.00 bucks and although seemingly pricey is almost without a doubt the source of you non igniting plight. Check ebay for them. I cannot tell you why they fail - but fail they do after decades of use and or non use, I think it has something to do with heat cycles on and off and internal corrossion.

My SL100 I picked up recently has no power to anything anywhere, but then again, Cooter had found the wiring harness and .. let the cuts begin, always with the ground wires.

Damn kids.......always with the ground wires:banghead:

Damn kids.......always with the ground wires:banghead:

:lol: yeppers!

Finally the new coil has arrived. Hopefully will get a chance to fit it in the next couple of days.

I will let you know how I go.

hope that does it, let us know

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