Go Back   PNW Moto > PNW Moto > Mechanical and Technical

Mechanical and Technical Mechanical and technical topics, help, and discussions

Like Tree2Likes
  • 1 Post By curve addict
  • 1 Post By FeralRdr
Thread Tools
May 5th 2018, 03:27 PM   #1
 curve addict's Avatar
  Apr 2016
  Des Moines, WA

  ...1987 Yamaha FZR1000...
Charging issue: sometimes ya just gotta keep looking

First off, sorry, no pictures.

My old 1987 Yamaha FZR1000T, with 31,000 miles, stopped charging this morning. As the alternator is a self-contained unit, I decided to look for and price another.


As some components, though expensive, are still available, I then went back to my old training and started diagnosing the components:
Wiring to/from alternator, good. Brushes, good with plenty of material remaining. I then removed the voltage regulator, installed the brush assembly and bypassed the regulator by clamping the brown-wire, armature, terminal to it's usual place on the brush assembly (+) and installing a jumper wire between the other brush's terminal (that usually connects to the regulator) and ground.

Started the bike and slowly brought up the revs: 16+VDC output from the rectifier. Shut the bike down immediately. The regulator had failed; all else OK.

The Yamaha voltage regulator listed for about $280. Ouch!

Having nothing to lose, I set about opening-up and inspecting the regulator as far as I could without destroying it. Found a cold solder connection that had started arcing and had finally corroded. Cleaned and re-soldered the connection, cleaned all other electrical connection points between the components and smeared a little dielectric grease on all of them, reinstalled the regulator, and started the bike. Charging and holding at 14.6VDC at 3000RPM and up!

Sometimes a little perseverance, and a little schooling, pay off.

Edit: here is a follow-up on that little job:Follow-up
Candiya likes this.

Edited by curve addict on May 20th 2018 at 04:43 PM
May 5th 2018, 04:30 PM   #2
 Rock Dodger's Avatar
  Feb 2016

Great job figuring that out! Most of us wouldn't know where to start on an issue like that.
May 5th 2018, 05:30 PM   #3
 Sentinel's Avatar
  Jun 2016
  Poor Tortured

  2015 Kawasaki Concours 14 - The Origame Sea-Dragon
i love it when people go old school and actually fix shit.

i fixed moms washer last week. the door switch had fallen apart. plastic crumbled. removed it and jumper-bypassed the circuit and told her to keep her hands out of it when it was spinning.

she said OK.

nice work, yo.
May 5th 2018, 06:12 PM   #4
 Scribbles's Avatar
  Jan 2016

I really like machines that are easy to take apart and fix. Too many newer contraptions require "buy a new unit..". I had a dishwasher with a failed pump (impeller was trashed), manufacturer told me that I had to buy a motor assembly to get that part as it wasn't offered by itself.
I bought a new dishwasher instead..
May 6th 2018, 08:22 AM   #5
 oldmanriver's Avatar
  Jan 2016
  Battle Ground

  2012 Kawasaki Ninja 1000SX
Can't help but think that it could have had something to do with a bad connector out in the boondocks. LOL
May 6th 2018, 08:59 AM   #6
  Jan 2016

Now we know who to call when the WiFi goes down.
Rock Dodger likes this.
May 6th 2018, 12:03 PM   #7
 curve addict's Avatar
  Apr 2016
  Des Moines, WA

  ...1987 Yamaha FZR1000...
Thanks y'all. It feels good to pull-off an inexpensive, quality fix every now and then. Sometimes I miss my little service business, Doctor Wheelgood, but then I remember losing all of my summers and then scraping by during the winters. Been thinking of looking for part-time work in someone else's shop for a little extra cash.

Originally Posted by oldmanriver
Can't help but think that it could have had something to do with a bad connector out in the boondocks. LOL
Possibly, but that solder joint was iffy from the factory. It finally gave out.

Originally Posted by FeralRdr
Now we know who to call when the WiFi goes down.
Yes, someone else. For good or ill, I avoid tackling internet or computer-related issues. I'm a primitive soul, after all.
May 6th 2018, 01:24 PM   #8
 Motorbiker's Avatar
  Jan 2016
  Silverdale, WA

  1987 FZR 1000
I have pretty much bypasses the original multi connector on my FZR1000TC myself. A few years in the SoCal heat and it was melting the connector. I have a complete motor, 125,000 miles before I dropped in 1994 motor in my 1987 frame. I also have a complete front fork assy with Racetech gold valves. Needs seals. Good job on the fix.
Jun 12th 2018, 10:32 AM   #9
 curve addict's Avatar
  Apr 2016
  Des Moines, WA

  ...1987 Yamaha FZR1000...
Too late to edit the first post, so here's more of the story

I had hoped to edit the first post, but ran out of time.

The old bugaboo has returned. An intermittent failure, the one that got me started on this merry chase, again reared its ugly head. Intermittent failures are the bane of all technicians.

This time, it failed to hide before I could find it.

(Note: I first checked this with the alternator in place, on the bike, brush assembly removed. I later pulled the rotor for show and tell.) According to factory manual, the resistance reading should be between 3.8 and 4.2 Ohms. My readings showed infinite resistance; an open circuit.

Charging issue: sometimes ya just gotta keep looking-alternator-info-body_rotor.jpg

Charging issue: sometimes ya just gotta keep looking-alternator-info-winding-open.jpg

Charging issue: sometimes ya just gotta keep looking-alternator-info-label.jpg

The field exciter coil had developed a break somewhere in its windings. There was no sign of overheating, but this can occur, over time, after many heating/cooling cycles. The break would open up and cause a charging failure. Later the broken ends would again touch and the alternator would work just fine.

This is one reason why most bikes now use permanent magnet rotors in their alternators. They're lighter and, unless the magnets break free of the rotor (seen that), the new rotors are pretty reliable.

Unfortnately for me, rotors for my alternator are available only as used, salvage parts. A new alternator is hard to find and beyond my current budget. On ebay I just found a complete, used unit from a seemingly reliable savage yard located in Virginia; lots of positive feedback. Wish me luck. I'll keep y'all posted.

Jun 16th 2018, 08:19 AM   #10
 curve addict's Avatar
  Apr 2016
  Des Moines, WA

  ...1987 Yamaha FZR1000...
OK, I found a replacement part. It looks a little different. The body itself is about 5mm larger in diameter and the end covers won't interchange, but it fits the hole, the parts inside appear to be interchangeable and it works. It turns out that the salvaged unit, Left, is likely from an earlier model 85/86 FZ750 or Fazer. Original 1987 unit on Right.
Charging issue: sometimes ya just gotta keep looking-p6140718.jpg
A little more information for those who are interested; the original, 1987 Yamaha part number, 2GH-81600-50-00, has been superseded up through at least 2GH-81600-55-00 for the same application.

At least two Nippondenso part numbers appear to apply here: 100211-4810, 100211-4880. The Denso part number of the older, salvaged unit is still unknown; label is torn.

Jun 16th 2018, 08:57 AM   #11
  Jan 2016

Sounds like someones ready for a test ride.

Might I suggest an ardent jaunt up and then back down Old McKenzie Pass.

It opens on Monnndaaaaay.

  PNW Moto > PNW Moto > Mechanical and Technical

charging, gotta, issue

Thread Tools
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
Charging system testing assistance needed Pavement Tested Mechanical and Technical 10 Oct 2nd 2017 04:29 PM
Gotta start them early Hyper7 Kitsap 3 Apr 15th 2017 10:49 PM
Starting issue 600bandit Mechanical and Technical 13 Jun 2nd 2016 10:05 AM
Clutch issue ltlpagan Mechanical and Technical 42 Mar 19th 2016 11:41 AM

Copyright © 2019 PNW Moto. All rights reserved.