Motorcycle Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
1,133 Posts
Discussion Starter #1
If you want to test a failed electrical system, the key is in the last note.. You, are testing a system. Not wires, not diodes, not the R and R(rest and relaxation hopefully).

rectifiers are the things that change the AC to the Dc and they do it with hightech electronic circuitry.

regulators are the things that keep the battery from overcharging, and turn the charger on when the voltage gets low.

just about all of these things work as a system, and the real key to fixing them is a schematic diagram of the circuitry.

The shop will entice you in to get your money using any one of these---

diode test
bad continuity
fuse block
connector somewhere

but mostly, if you are fixing things in your shop, and something fails, you will end up buying an entire system to fix the problem.

USUALLY- you will be faced with a worn or smashed wire, that is shorting out to the frame, a bad connection, or a component that has simply failed.

It's usually the regulaor that fails in an R|R, not the rectfier. rectifiers are hightech, and only fail when there are other major things wrong with the system.

do good mechanics ever need help? not usually!
My clymer manual says there should be about 3.5 ohms between the 2 connections on the regulator that power the electromagnetic free induction field coil alternator on my 80 XS, but the wiring is different than the diagrams given in the manual, and seems more like the XJ than the XS.

This is some of the shop work I am talking about.

I have a shop(thank the stars) and I grew up learning about mechanics and heavy equipment.

Take the time to do a thorough system check for anything that might be wrong, then check the manuals and books if you don't find anything.

good luck. im me if you really have a stumpping going on.
 

·
Registered
Joined
·
10 Posts
A friend and I bought an 87 Radian with 3000 miles looks almost mint. We went through the carbs and got it running great... minus the charging system. We do have a new (fully charged) battery in it but the system is not charging. We have been trying to follow the manual and got to where it's telling us we have a bad field coil. Our resistance reading is now where near spec. The brushes look fine but under the stator cover everything is a bit dirty.

Been trying to read and getting stuck with almost too much information out there. Was hoping to find some advise on getting to the bottom of this.

I almost forgot, all the wires look really good. I haven't pulled them all to look for corrosion or bad connections but haven't found any yet. The one thing though, someone has done something to this bike... the r/r is not original nor for this bike I don't think. Maybe that's our whole problem.
 

·
Pale Rider
Joined
·
528 Posts
The alternator should pump out AC voltage and current, from three yellow wires, assuming it is a 3-phase alternator. The Rectifier converts this to DC voltage and current; the Regulator portion keeps it from climbing too high in voltage, usually limiting it to <15.5 Volts.

If you followed the manual to troubleshoot the system, did it require you to measure AC Voltage at/between some yellow-colored wires? Did you measure the specified AC Voltage? If not, either the Stator, or Field Coil, is bad (open wire), or the Stator's electromagnet is not receiving DC current from the battery, which powers it -- bad connection to the battery?

The manual should cover the troubleshooting thoroughly, and both situations described above should be covered in the troubleshooting process. If you followed the manual carefully, and it says the Field Coil is bad, it likely is. The Field Coil is a large coil of copper wires (lots of windings of thin, insulated, copper wires); the Stator's magnetic field cuts through the Field Coil's windings, as it spins, generating AC electricity, in the yellow wires. The Stator is an electro-magnet, which draws power from the battery to generate its magnetic field. The faster the Stator spins inside of the Field Coil, the more Voltage, and Amperage, it generates within the Field Coil -- more power. The R/R converts the AC to DC, and limits it so that it powers the bike, as well as charges the battery, without over-charging it (limits the DC Voltage to prevent damage). Cheers!
:coffee:
 

·
Registered
Joined
·
10 Posts
Thanks for the reply, we followed the manual but there wasn't much too it... the 3 wires coming off the stator we should get .5-.6 ohms (which we did) and from the 2 off the field coil brushes be at 2.7 - 3.3 (we were at 46.6!) Someone told me not test that way but to go directly to the slip rings, after trying that, come up with 4-5 which is at least much closer. After cleaning everything up and resemble get about 9 when measuring from the wires before they go into the rectifier.

We decided to stop for now until because the rec/reg is obviously not stock, the bolt holes don't line up and the wire harness has an 8 pin plug but only 6 wires but should be connecting to 7. It has 2 wires coming off with another plug and could maybe rig something up but we found a used one (said working) on eBay for $15. Going to work on something else for now and hope to get lucky that fixes it!

I'm kind of dumb still with this electrical stuff but hope to learn something from you guys. Thanks again!
 

·
American Legion Rider
Joined
·
20,037 Posts
You are already doing much better than some of us here.(ME!) I hate electrical problems. But just listen to the experts here and you should get it all figured out.:thumbsup:
 

·
Registered
Joined
·
1,133 Posts
Discussion Starter #7
charging system?

The deal here, I found last year, is that the alternator creates a charge when it runs through the regulator- On my XS it is a combo- regulator rectifier.

The only thing other than the rectifier that might keep a system from charging is a bad wire, connection or relay--- between>>>
the battery,>>> the regulator>>>The alternator
if everything in there has continuity, the chances are its the regulator.

I pulled the entire wiring harness on my XS, tested it for about 3 weeks, found a busted wire.... finally after all that, I replaced the regulator with an original OEM one I happened to find on Ebay. Charges like a trooper now.

good luck with a custom set up... you might try changing it all back to OEM?
 

·
Registered
Joined
·
1,133 Posts
Discussion Starter #8
forgot one thing....

some times there is a diode beween the regulator and the alternator to keep things going in the right direction.... if there is, get a new one.
 

·
Registered
Joined
·
10 Posts
You were definitely right. When I realized one of the wires from the bike harness went to an empty slot on the r/r connector and there were 2 wires coming off the r/r with no where to go I knew my first step was to replace it. Not to mention it didn't quite mount right (and I found a used oem for $15) it was a no brainer. Plugged it in last night and, bam, 14+ volts.... Now to figure out the bonded title in Iowa. I really hope it's not too hard, the bike looks and runs like new.
Thanks everyone!
 

·
Registered
Joined
·
10 Posts
Oh, (going to browse eBay later) but if anyone knows where I can get a pair of those ray gun looking carb covers and a left side cover that says radian on it that should be the last thing I need to do.
 

·
Pale Rider
Joined
·
528 Posts
I've shared this book before, but it bears sharing again: Motorcycle Electrical Systems: Troubleshooting and Repair, ISBN: 0760327165. Best book I've found yet, on bike electrics: theory in easy-to-understand language, with excellent diagrams; how to make simple diagnostic tools, as well as how to use them properly; great troubleshooting explanations. If you have difficulty understanding bike electrics, or just want quality instruction on how-to, this is a fantastic resource, worth every penny.

If you want to install a sub-fuse block, this book will show you how, as well as help you understand, and calculate, how much you can expand your fuse block, without killing the battery. It has more useful information, as well, but this is just an example of what it can help you with, like testing for voltage drops in high-current wires, diagnosing the charging system, etc. Cheers!
:coffee:
 
1 - 12 of 12 Posts
Top