The International CBX Owners Association

Hi everyone! I'm a brand new member, having just picked up my '79 CBX yesterday. I'm tremendously excited to have it, and can't wait to get it into tip-top running condition.

While going through the bike, I noticed that the red connector under the right side cover in the connector stack is melted--presumably, according to my reading, through corrosion and subsequent heat build-up. Seems that this is a common issue. However, could someone kindly point to me the name/tech specs of the replacement connector I need? I've read many forum posts on this, checked the OEM parts diagram, and have looked on CycleTerminal, but can't seem to figure out exactly what I need. It's the third connector from top, with four wires. Picture attached.

I'm also going to go through all the other plugs (especially the alternator ones) and see what's what. Thanks so much in advance for any help!

PS: I bought my bike from someone who was a longtime Honda dealer in Pennsylvania. He sold this exact bike new to a customer in 1979, who kept it until 2013, until the dealer re-bought it. The bike came back to the dealer with his handwriting on the warranty card, etc., along with original brochures and paperwork. I love this backstory!

This is the connector you need (4 pin 6.3mm - .250 Male and Female locking connector - Connector with Terminals Flange Type Female). Not the OEM red color, I've read that some of these connectors are available from Honda if you insist on red.

http://www.cycleterminal.com/250-connectors.html#SC250

The plastic connector body is only the 'holder' of the spades that mate to create the electrical connection. The heat is produced by resistance in that mating, largely due to corrosion forming on the mating surfaces over the past 40+ years. Cleaning up those mating surfaces is critical to reduce that electrical resistance but when the connectors overheat that much the crimp around the wire can be compromised as well due to corrosion. If you're already taking those connectors apart I would change the actual spades on both sides. You'll need the tool at to bottom of the CycleTerminal page to properly crimp those connectors. All the current the alternator/regulator produces moves through that connector and when the battery is run down that can be significant.

Reducing the overall electrical current draw on the wiring harness is a good idea by switching to LED lights and checking the harness for any built up resistances that causes more current draw. The ignition switch is one place to look as well.

Thank you so very much! That's very helpful. I was having a devil of time trying to figure out what I needed. I'm going to order the connector you listed, together with a bunch of extra male and female terminals whose specs match the connector (the 6.3mm - .250 Brass male and female terminals, .5 - 2 mm). I have a couple crimping tools already, but I'll also get the crimping tool Cycleterminal lists.

I'll also do some digging on the LED lights conversion--I'm sure there are plenty of posts here about that. I'm sincerely hoping that fixing this connector will address the charging issue (voltage drops into the "red" zone below 8v at idle, and the bike dies). If it doesn't, I'll test the alternator, reg/rec, and various connections. Fingers crossed.

Thank you SO much again!

You've got something going on if the volt gauge is that low at any time. What is the voltage with the ignition 'on' and the bike not running? Should be what the battery voltage is (~12.7V). If it's much lower than the battery voltage your battery could be failing or there is a high resistance load somewhere other than that connector. If the voltmeter picks up to something over 12V with some revs would suggest the alternator is doing something. Definitely need to repair the connector you ID'd first and load test your battery.

Yeah, I suspect something else is amiss. I tested the battery separately, and it's holding a healthy charge at around 12.7v or so. I noticed and was confused as to why the voltmeter shows only around ~10v with the ignition on, but the bike not running.

So if the battery is ok and the alternator could be ok (volts do rise with higher revs, so it's not totally shot), there must be a load issue somewhere. Perhaps another burned/corroded connector? I'll check the ignition/kill switch housing and other common problem areas that have been listed. I'm ok at purely "mechanical" work but terrible with electrical gremlins! Thanks so much again for your help and advice.

Sounds like you have a corrosion issue somewhere between the battery and the volt meter. Given that you already have found one badly corroded connector, I'd take voltage readings to find where the lost electrons are hiding.

It seems like it! Should I understand from these answers that the corroded red plug featured above is likely not the culprit? Since that connector carries power from the alternator/RR, I'm not sure if that's part of the circuit with the battery off.

exygenysys wrote: ↑

Mon Jun 06, 2022 9:16 am

It seems like it! Should I understand from these answers that the corroded red plug featured above is likely not the culprit? Since that connector carries power from the alternator/RR, I'm not sure if that's part of the circuit with the battery off.

If both cables are connected to the battery, there should be power at both red wires in that connector (assuming the "dogbone" fuse is conducting electricity). Key on or key off, always energized.