CRAP!!!

I made an earlier post about a strange burning plastic smell coming from the area of my rectifier. I smelled it a bit last night, but thought it might be the hot weather working the fans a lot making the rectifier smell a little. Didn't see anything wierd, but today it got worse.

When I got home from work it was stronger. I took off the seat and noticed the plastic cover over the wiring harness under the seat had discolored. I took it apart to find the problem. The connector from the stator that connects to the rectifier had melted, and the wires on both sides of the connector were now bare.

When I bought the bike the previous owner said it had recently failed and melted the same connector. One side had been replaced and was plugged into the remaining side that did have a little discoloration as I recall. I'm now wondering if the wires had been damaged causing heat build up. It has run normally for 3000 miles. This must have just recently happened, possibly hurried alone buy the very high temperatures here in San Fran recently.

My plan is to cut the wires back several inches and replace the burnt sections of the wire on both sides. Then just use male and female ends to connect the rectifier and the stator back together.

What do you think? Might there be others problems that might have caused this? Bad ststor, bad rectifier - again. The battery came out of the bike with over 14 volts in it. so it is definatley charging. No other electrical problems experienced. No extra electrically powered equipment added to the bike.

[IMG]local://upfiles/6897/A13E58A32F274C149C2A0621128FC2FB.jpg[/IMG]

[IMG]local://upfiles/6897/41937D6CD2A443A18F97DAEC3A6F691F.jpg[/IMG]

 

Have you measured the current coming out of the rectifier at higher revs, i.e., 5k and up? I think that once you fix the wiring, that is the first thing to do: Measure the current out of the stator, then again at the battery.

FWIW, all three of my rectifier wires get really hot as well. I don’t know how the wiring sits in the bike, but it looks like the three yellow rectifier wires are very close to the others. If it were me, I think I’d find a new wiring harness. I bought a spare for $35 on eBay. Splicing all those wires will be a nightmare. That’s a lot of solder.

--Chris

 

The rectifier had burnt out before, and took half of the wiring harness(from rectifier to stator) with it. I replaced one side of the harness and wiring but continued to use the other side. Bad idea. I think the heat from the first burn out damaged the wiring/connector a little making the plastic softer and the wires have more resistance. This time I replaced everything. The wires all the way to the rectifier connector, and about 8 inches down toward the stator until the wire looked new again. Then just went with real good quality insulated male/female connectors to make the connection. I also added a ground strap to the bolt under the rectifier as the plate on the bottom of the rectifier is supposed to ground against the chasis and I don't think it was very well. All other connections/voltages/resistances are to spec. Adding the ground strap has kept the wires from getting very hot at all. The rectifier now gets hotter than it used to, which I think is the way it should be.

It seems to be working perfectly for the moment. But I still stick my nose under the seat everytime I ride it to double check.

 

So your rectifier is still good?

 

So far so good. No one was more supprised than me.

At idle there is about 14.2 volts going to the battery. At 5000 about 13.5 volts. This is what iremember, it was a couple days ago when I checked it last.

I got another rectifier from a guy who was parting out his 900RR, plugged it in and got the exact same numbers. I got the exact same voltage as the battery from the red wire that goes into the rectifier. The ground is good. Resistance on the three stator wires was about .4, under spec. I'm getting 50 volts from all three stator wires. Also to spec.

I just think the connector was damaged. Without the ground strap going to the rectifier case the wires were geting pretty hot. I think they started touching one another in the connector, causing the meltdown. Now with the case grounded the wires aren't getting nearly as hot, just barely warm.

We'll see how things play out, but for now it's OK.

 

I've never seen a wiring diagram with the rectifier grounded. Mine isn't right now, but it is mounted to an aluminum plate that is riveted to the chassis. Do you think I should run grounding wire from a bolt on the rectifier to the chassis?

--Chris

 

I've never seen it on a diagram either. However, the reason most rectifiers go into an overcharging state is bad grounding. Either through a poor connection through the chasis/engine ground, or low voltage detected by the rectifier through the wiring harness.

Often with older bikes the ignition switches add additional resistance into the circuit, which the rectifier thinks is low voltage in the battery. Then trys to fix the problem by overcharging the battery, leading to dead batteries and burnt out rectifiers.

One solution is to ground the rectifier(specifically those with a metal plate on the back) to the negative pole of the battery. The metal back plate is supposed to ground against the frame, but aluminum gets an oxidation coating on it after a while and the ground becomes ineffective. Adding an additional grounding strap to one of the bolts going through the rectifier inbetween the rectifier and the frame fixes the problem.

On bikes with persistant problems with rectifiers, I've even heard of running the red & green wire from the rectifier harness directly to the positive and negative sides of the battery so the rectifier gets a 'true' reading of the battery voltage.

 

Hey guys I know this was a long time back that you we're talking about this but after searching the forum this is the most similar instance to my problem I can find.

Bassically my bike is doing the exact same thing, the wires coming from the connectors are fried and fell apart, noticed when it wouldn't start this morning, though they have been slowly melting this past week but I didn't think it'd fall apart that fast. My question is how important is it to have the connector between the wires? I only ask because I can't get a new connector until this weekend but if it's not needed I'll just splice new wires and directly connect them (without the 3 prong connectors). If anyone out there knows wether this is a good or bad idea please reply ASAP. Thanks!

 

I just had the same problem and replaced the wires and got it going again. There are 5 wires going to the rectifier, one is ground two is positive current and the other three are called the three-o's, they come from the stator. Everbody saya this is a common problem with honda. Johnny

 

DMAC, & others

Man that sucks for sure, but as they say been there and the hole "T" shirt **** to go with it as well. [:'(]

The early CBX's are prone to having this problem, but there is good news as there are some places for parts and ways to check out the charging system. The main reason for a melt down in this area is caused by corrsion between themating connectors. When there is corrsion the path gets harder to push through and heat upto the point of that dreaded melt down.....[sm=boohoo.gif]

Now for checking the charging system, http://www.electrosport.com/electros...t_finding.html there is a fault finding flow chart down on this page.[sm=smiley20.gif]

Also for the connectors, http://www.vintageconnections.com/ they carry everything to repair a wiring harness.[sm=smiley20.gif]

Good Luck,,,, rememberthe biggest pain in the *** is not cleaning these connectors about once a year.......[sm=headbang.gif]