My suggestion is similar as to the atc110, but there are a lot of wires, so you'd want to narrow down the search. Assuming your machine is a 1985 since that's the most common (86-87 should be similar anyway)
Disconnect handle bar switch and test black/white wire to green with kill switch to on, should be no connection. Test the same wires on the harness side with ignition switch to on, again should be no connection. If there is a connection, the CDI is being signaled to not spark and you'll need to test the ignition switch or kill switch directly and replace as needed (unlikely).
Next I'd pull the CDI out for probing. Green wire to clean engine ground, or the frame ground location should have solid connection. Grounds are pretty critical so never hurts to validate it's good. All solid green wires should be the same connection at any point in the harness.
The big red has a neutral and reverse safety switches. With a battery and key on and machine in neutral, the neutral light should light up. If it does not, either there's a poor connection, bad safety switch, or burnt bulb. Both safety switches connect to ground with enabled (aka when in neutral, neutral switch connects to engine ground). I suspect this is the likely cause since it's near the bottom of the engine under the little metal cover. I sell replacement sub harnesses for them using plain bullet connectors (no rubber housing around them). If one of the switches test bad, you can buy them from Honda yet. I've had a machine with shifting problems also cause the no spark problem and no neutral light, getting it into neutral gear after disassembly fixed the ignition problem.
Ok, if all tests good by this point then I'm thinking a bad wire or CDI. CDI is easiest at this point if you have a known working one, or can borrow one. I kind of hate to suggest buying a CDI since they can be expensive. Connection quality can play a large factor and could make a good cdi appear bad.
Probe time for the rest of the CDI pins....
Green we tested already
Black/Yellow goes to the coil
Black/Red goes to the alternator area on the engine (bullet connector)
Blue/Yellow & Green/White goes to the pulse generator @ the same general location as the alternator connectors (3 pin connector)
Black/white goes to ignition switch and kill switch, generally when the wire fails, there won't be a connection, which would fail in the can't stop the engine running style.
If everything tests good, might have to go over the individual component tests again to be sure they are in fact good. My bet is the neutral safety switch wire though, most of the machines I've seen had pretty corroded up wires, or the connectors were very loose and made poor connection.
The rest of the wires are for charging, starting, lights, etc and shouldn't effect the ignition system.
I have a 250es
service manual if you need any specs.
I almost should build a website with step by step troubleshooting steps and common problems lol.
Originally Posted by Dgonzo
Roostin' Away
Arm chair racerRoostin Away
Reply With Quote
