symptoms of busted rectifier/regulator

I have had all kinds of problems with my bike since I got it. They all seem straightened out now except for problems starting and the battery running down. Looked at the rectifier harness and the red wire obviously overheated because it melted through the connector and possibly grounded against the frame. I ordered a new one off ebay for like 30$.

What kind of problems would a busted rectifier cause? Other then not charging/over charging the battery. Should I look at replacing the diode pack in the headlight? Hopefully this is the last problem I will run into.

 

That "Red Wire Melt" is a common indicator that the Bike was Jump Started for having a Dead Battery.

In more than 90% of the time ... the trouble was traced to Alternator Brushes.

The Brushes get worn out and the Charging Current is affected. The Battery gets drained and goes dead.

A Jump Start helps get the bike running ... But, the wiring to the Regulator gets fried trying to Regulate the BIG Amps from the Vehicle the Bike gets hooked-up too.

Before you get too far ahead of yourself ... Pull the Alternator Cover and measure the lengths of the two Brushes INSIDE the backside of the Alternator Cover.

11mm or LESS ... You need new Brushes.

You probably do!

 

The brushes are far from their wear line. I didn't measure them but I could clearly see the line and it was far from the end. I also sanded the carbon off the plate they hit, no burn marks or anything. How is the starting circuit affected when the rectifier is fried? Not at all? Im hoping that the new rectifier and battery will fix the problem.

 

Can't hurt to try a New Battery ... But, before you pop for the $79.95 ... Take the one you got out of the Bike and charge it.

Then, bring it someplace that can "Break it down" and tell you how deep a charge it holds and measure Cranking Amps. You may not need a new battery.

But, it sure sounds like you need a new Voltage Regulator.

 

Rick - I paid $29.95 for a new battery at Batteries Plus.

 

$29.95 for a Battery?

Those poor starving children slaves at the battery plant ... !!!
How could you???

 

I tell ya, there is a Batteries Plus store just down the street, and I was pleasantly surprised. They had a huge selection of car/MC batteries, all very competitively priced. They even had the Battery Tender Jr. for $29.95, which is the online discount price.

They didn't have maintenance free battery, but they did fill the battery with electrolyte and offered to charge it for me.

 

You won ...
If the Battery lasts for a couple of seasons.

We have some COLD, Cold weather over hear, near Boston.
I go with the Sears DieHard Model that fits the 750 Maxim -- the DeLuxe one.

 

Yeah mine was like 40$. I took my old one to autozone and they tested it.. no good. I should of sprung for a better battery in the first place and maybe I wouldn't be buying a new one right now.

 

Winner. Close the thread. Everybody go home. That's some comedy gold right there.

 

I discovered red wire connector melted on the rectifier/regulator connector when tearing my bike down. I plan on cleaning connections according to the posts on this site when I rebuild, but nothing is on the bike so I can't test it now. Should I just pick up another on ebay before I begin? Can I just assume that a regulator listed is good if it doesn't have a melted connector? I think I saw on a different post by Rick that they were outsourced and therefore common. What would/wouldn't be compatible for an 1982 xj750rj seca?

(sorry to reopen the thread, but it seemed like the most relevant place to ask)

 

Don't assume the Regulator is shot.
Test it.

First, do a repair.
Push the Red Wire back into the Clip as far as its supposed to go.
Make a Dime sized batch of Epoxy and epoxy-weld the Red Wire back into place.
10 minutes leter you should be able to test it.
Run the Bike and monitor the Voltage.

The Voltage should dip to 11 Volts with the Starter Motor running.
The Voltage should rise once the bike is started.
11.5 Volts to +12 Volts at lower RPM's

12 Solid Volts at 1750
Increasing to 14.2 Volts at 2,000
Steady 14.2 ~ 14.5 at 2,500 and Up.
Never exceeding 14.8 which is trouble.

Low Voltages can be Alternator Brushes failing.
Measure the Brushes
10.5mm or Less Replace.