My new charging system

[xjwmx]

New to me anyway.

One recent cold morning my bike wouldn't start due to weak battery. I poked around with a meter and discovered that downstream on the red wire the voltage was lower than the battery if the bike wasn't running but higher if it was! About 1V difference.

That could mean only one thing - a high resistance connection. I traced it to inside the harness, where a twisted connection was which I didn't know was there. I dont have soldering stuff with me, so I crushed the twist with pliers good and taped it back up.

Now, why I say new charging system. Apparently the twisted connection has been a problem since I've owned the bike. The V at the battery would always work its way up to over 14V, but it took awhile. Now it shoots up to 14V as soon as you twist the throttle, and tops out around 14.5V. Soon as I get more settled or can borrow a workshop, I'll undo the temp fix and do it properly.

 

[Mollard]

I am NOT looking forward on doing the electrical on my restoration......

I guess it will be a learning experience....

 

[xjwmx]

^For you, if I had it all to do over again I would buy a new harness, I think Mike's sells a full harness at a good price, and do it that way. It eliminates potential unknowns, and also eliminates old connectors, which are a problem.


I thought what I was always seeing was normal, because the charging system gets callled poor so much.

 

[XSLeo]

Several people have said that the voltage rises slowly. Perhaps they have a weak connection in their harnesses too.
When you do fix yours, perhaps a few pics showing just where your bad spot is will help others check theirs.
I have taken stock harnesses apart for the parts and have found the way the factory splices wires to be poor at best. On the main red wire from the fuse up to the key switch has splices where the rectifier hooks on. They cut off a bit of the plastic, lay the other wire against the bare spot, slide a copper tube over the wires and crimp it, wrap with tape.
Not the best way, but fast and cheap.
Leo

 

[littlebill31]

Whenever I get a new-to-me bike I go over it and replace things first. Like the oil. Even if it was just changed I change it again. Brake pads, fuses, ect. With my XS's I have been getting a new harness from MikesXS and changing it out. Most of my harness' were/are good enough, but those 30+ tr old wires are too scary for me. When I did my first harness I found dried mud that was powdery inside the original sheath around the wires. Many connections were corroded and extremely brittle. So now it's an immediate change out for me.

 

[xjwmx]

I changed the op to read higher and lower in relation to the battery voltage, which was what was happening really.

A pm put in a new fuse box, which is a good one, but the connections to the leads from it are just twisted! Got to go pretty far down the tape in the harness to see it.

 

[xjwmx]

Leo, electrically where the bad connection was was on the downstream side of the main fuse, and before anything else. So when the bike was running, the full charging voltage couldn't make it to the battery, and when the bike was off the full battery voltage couldn't make it past the connection. So on the other side of the connection it was a volt higher than the battery when the bike was running and a volt lower than the battery when the bike was off.

 

[CDNTX650]

Along with a new harness on every old bike (i build myself) i always do a new solidstate regulator from oregon motorcycle parts, and build a new rectifier.