1985 250ES Big Red No Spark again!

[SRTMack]

So I got a Big Red! I was raised on them in Texas and excited I found one for a good price! I was riding it for a few weeks then it died, but keep reading I am pretty sure I know what is wrong. I just want to make sure before I start spending too much money after all money does not grow on trees!

Few items to let the members know:
Key switch was lost so has toggle installed.
Was running until I shut it off and would not restart.
Lights come on, and neutral switch works.
The main fuse has been rewired to new blade fuse.

Found manuals online and troubleshoot the system down to a CDI, I think.

ohm out the kill switch and it works in all three positions.
The toggle switch is wired correctly and in working condition. The off wires are not touching and disconnected.
I do get a signal to the starter relay, but the starter won't come on. I jumped the starter, and it will spin.
Coil seems to check out with ohms and is tied to neutral switch and headlight, which both work.
Yes, I do have the battery fully charged and on a charger now until I get it running. Hey just tossing it out there.
Checked fuses in the front and both are good, and the main fuse is working as well.
Pulled the spark plug and I can not get a spark from it.

Unless I am wrong, it does seem to point to the CDI.

Also, I was reading the forum to swap over the CDI to a different plug, but unable to find all the parts listed in the sticky.

Any help guys would be awesome!

[SRTMack]

Forgot to tell you, the starter button does work, but it will not turn over. It seems like something is keeping it grounded out to keep it from starting.

[atc007]

Get a 250ES keyswitch and go from there.

[Rob Canadian]

I would be starting with why it is not turning over via the battery and start switch. Jumpering the starter does not mean you have power to where power needs to be.

[SRTMack]

already coming in Friday, but used the wiring diagram to make sure that's not the issue.

[SRTMack]

By jumping the starter, it shows I do have power, and the starter is working. So I ohm out the start kill switch its self, and that is working correctly. Next, I ohms out the start switch at the starter relays, and it does ohm and sends power. Also, the ign switch ohms too.

[SRTMack]

I put the key switch in and it works, but the machine will still not start. I have a new CDI with the 4-2 harness to go in. I will get that in and let everyone else know.

[SRTMack]

So I got the new CDI in and switched the CDI to a 4-2. https://www.amazon.com/gp/product/B0081TGQ6Y/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 is what I got and it works great. Now that it is a 4-2 CDI will be eaiser to come by.

Yes, the CDI was the issue and it is not alive.

[350for350]

I'm having the same issue with mine. Do the colors on the wires match?

[SRTMack]

The wires did match up for the most part with that harness. What I did was use the manual to convert it from the 85 round style to the 86 4-2 style to the correct position. The only issue I have currently is the neutral switch will not turn off when I place it in gear, but that is directly related to the CDI that I am currently using. I am sure I can find a better CDI, but it works, so I will let it ride out for now.

You say you are having the same issue.... Do you know for a fact your CDI is bad? I ohm mine out and that's who I knew before I went to buy one.

[350for350]

Yes I did the ohms test on mine too. It failed on several circuits. I did order the same CDI as you did. I'm hoping to get mine running again next week. I'm not ral great with wiring, but I'm willing to give it a try.

[SRTMack]

I used the manul to show and just swapped from the 85 to the 86-87. all the wires will just hook up in a different location, but they all should hook up. When you get ready to move the wires over, just make you position the CDI in the right direction so you can see what wires go where.

[BoxerBoss]

I used the manul to show and just swapped from the 85 to the 86-87. all the wires will just hook up in a different location, but they all should hook up. When you get ready to move the wires over, just make you position the CDI in the right direction so you can see what wires go where.Buddy .. not sure if already solved but check the plastic wire male/female plugs.. one of them had corrosion for me and a simple clean up did the trick. Good luck.

Sent from my SM-N950U using Tapatalk

[350for350]

I used the manul to show and just swapped from the 85 to the 86-87. all the wires will just hook up in a different location, but they all should hook up. When you get ready to move the wires over, just make you position the CDI in the right direction so you can see what wires go where.

Thanks. Now to find the time to try this.

[SRTMack]

I have pulled out the CDI and bench tested it by ohm the CDI out. The CDI was, in fact, bad after all it was original and 34 years old.

[ICS Vortex]

So I got the new CDI in and switched the CDI to a 4-2. https://www.amazon.com/gp/product/B0081TGQ6Y/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 is what I got and it works great. Now that it is a 4-2 CDI will be eaiser to come by.

Yes, the CDI was the issue and it is not alive.

Did you convert your 85 wiring harness to accept the 4x2 plug using the linked CDI and wires? Also, did you actually use that CDI linked or did you use an actual 86 Big Red CDI?

[ps2fixer]

Figured I'd chime in and confirm that the 85 and 86-87 wiring is the same for the CDI (colors) across both machines, only difference being the connector. I don't recall if the whole harness can be interchanged on it's own, seems like there was another connector that changed too. Also note aftermarket CDI's should work just fine, the biggest thing to have right from my understanding is AC vs DC powered CDI, the wire pinout match the connector (it does change a little machine to machine sometimes), and the spark advancement curve might be off from stock. Like I tested a China 4+2 CDI on my 350x and the timing wasn't advanced enough, was hard starting and reving it up it was back firing and wasn't happy at all, stock one it runs perfect on though.

You can remove the round 6 pin cdi connector from your harness, and install a new 4+2 style cdi connector (linked below for one of my suppliers, min order is $5). You'd want the terminal removal tool as well or a long very small flat screw driver. The better option in my opinion is to cut the old connector off and replace it with a pig tail so all of the terminals are new. I can make them at request but I'll need to know what pin out to use.

4+2 style CDI connectors, look near the bottom of the page - http://www.cycleterminal.com/motorcycle-connectors.html
Terminal Extraction tool (you need the smaller one) - http://www.cycleterminal.com/crimp-tools.html

I can also make OEM color matched pig tails using high quality Japanese connectors, shoot me a pm if you ever need one.