No spark while cranking

[oscar]

Hey Fellas, I'm working on a 87 TRX 250 utility(don't throw stones, I'm only fixing it to sell so I can buy more parts for my R) Anyways as near as I can tell this thing is a 87 250 ES Big Red or (250SX) with 4 wheels. One of my problems is I have no spark while cranking the engine with electric starter, as soon as I let off the start button I have spark and the engine runs great. Just no fire while cranking. It will start if I kick it over, with key on.

Anybody got any ideas where my problem maybe? It must have something to do with the start circuit, the run circuit is fine. I'm too cheap to buy a manual (for the schematic) and this isn't a tough problem. Does anyone know what the two wires on the starter solenoid are for? I assume one wire comes from the starter button and the other comes from the neutral safety switch. I don't think it's the solenoid. Anyone think if my problem is in the starter button maybe corrosion or dirt? Or is there some other little black box somewhere relay or something? Anyone got a manual? Can you follow the circuit for me?

I've haven't had a chance to troubleshot this too much yet, hopefully tonight. I'm trying to get my brother's X cylinder to the machine shop for a bore, it burned over 2 quarts of oil through it this weekend. We didn't see many mosquito's......

[oscar]

I did a little research on the other 3Wheeler website and looked at a 87 SX wiring diagram, looks like it may be the G/R wire going into the CDI. Maybe a bad connection, or bad CDI. My neutral light comes on and stays on while cranking while in neutral just like it should. So it must be providing the ground, I just don't know if the CDI is seeing that ground while cranking??? Doesn't look like the ignition switch or kill switch have any relationship to the start circuit.

Anybody ever have a similiar problem?

[oscar]

I fixed this the other night. I was tracing wires in the harness, I found the two wires going to the neutral safety switch and reverse switch had been cut and then twisted back together then wrapped with electrical tape. While testing with a test light everything checked out ok and functioned like it should. I took it apart cleaned the wires, crimped them with a butt connector then covered the whole thing with the liquid electrical tape to seal it up good.

It works fine now. I have spark while cranking. It starts immediately. This was one of those electical gremlins you can never really figure out. I can only assume the dirty twisted together connection was the cause but it still had continuity so I don't get it. Must have had too high of resistance across the twisted connection?????

[ATCnut]

Good Job in finding the problem. Trike Electrics are the hardest to fix (even for me and I'm a Electrical Engineer)

[oscar]

Me Too B.S. EE Kind of embarassing that I couldn't figure it out right away (actually I spent more time typing all this in than I did troubleshooting and repairing) that's why I think it was just too high of resistance but still had continuity (with a test light) but the CDI couldn't see the ground from Neutral safety switch while cranking.

Who knows but now it starts on the touch of button not bad for a $125 wheeler, now I need to sell it to pay for parts for my other R....

[dads]

Originally posted by ATCnut
Good Job in finding the problem. Trike Electrics are the hardest to fix (even for me and I'm a Electrical Engineer)



:doh: Well ATCnut, That’s because an electrical Engineers, can't fix what they designs. That’s What use Techs are for.
Make it work, and fix it when it breaks.


:demon: :lmao: