R/R Connector Issue

[steveotmc]

A few months back I was riding on the highway (65+MPH) for at least fifteen miles, it was pretty hot, but the temp gauge was fine and the bike was running well. I get off, and after accelerating from the off ramp the bike just dies. I lost all electronics and the battery was STEAMING. After letting it cool down, and hooking a new battery up, it fired up just fine, but I suspected that the R/R was faulty because the stator was new last summer. So the output on the R/R looks melted, does this mean the R/R is bad or just the connection? Like I said everything else works on the bike (except the headlight bulb low beam burnt out... I'm suspecting due to too much voltage from the R/R) so does anyone know what could be wrong?

[Rikugun]

So the output on the R/R looks melted, does this mean the R/R is bad or just the connection?

It's tough to say after the fact. The melted bits are not uncommon in older bikes and can begin with corroded or otherwise compromised connectors. It's also not uncommon for the R/R to simply fail as well. Or, it was a combination of the two.

I'm assuming the battery is toast and will be replaced. I'd next verify the stator is still good by checking resistance and AC voltage output of the 3 legs. The values will be dependent on the particular make of stator which is why it's a good idea to check things when new to establish a baseline. Having said that I'd think maybe half an ohm resistance (or less) and 50+ or so volts AC at 4-5k RPM's. It's important the values are equal between the 3 legs for both checks not just the absolute values.

As far as the R/R goes, you might consider starting with a new one - maybe even one of these fancy serial types all the kids are using nowadays.  :) If you want to try the old one (which I'm assuming is a conventional type) I'd extend the length of the red and black (with the correct gage wire) and go directly to the battery plus and minus with soldered ring terminals. Obviously the 3 stator and brown voltage sensing wire connections will need to be redone with quality soldered connectors. Some opt to solder the wires together foregoing connectors.

Run the engine and check battery voltage at various RPM's. High 13's to mid 14's would be nice whereas 15+ is probably too high. If it is a little high, you can try soldering the red and brown together near the battery plus terminal which will trick the R/R and may lower output to an acceptable level.  All dynamic DC tests are to be made with a fully charged GOOD battery.

[steveotmc]

So how am I to test the stator with the bike running? I'm sure there's a link somewhere but if you know off hand or at least which link let me know please I would appreciate it, I'm guessing the different wires being inputted to the RR are connected to different positions in the stator? I would buy a new RR but $150+ for a part I already have, albeit better, is kinda out of my price range unfortantely.

[Rikugun]

There's no magic to the order of the stator wires as they're connected to the regulator or being tested. For testing purposes you will need to keep track of them however. Consider them to be A, B, and C. This same methodology is used to check resistance (ohms) through the windings BTW except here you'll be using the AC scale of your meter.  Also, when doing resistance checks you'll also test each of the stator wires to the engine (ground) using a mega-ohm scale and hopefully find no continuity.

Start the engine and hold the red probe to A and the black probe to B and note the voltage at a given RPM - say 4K. Then do the next leg of the stator by leaving the Red probe where it is and move the Black probe to C. Finally, move the two meter probes to read between B and C. The polarity doesn't matter as you are testing alternating current meaning the pixies are dancing back and forth in the wires.  ;) To recap, the order is A-B, A-C, B-C. I'd be surprised if you didn't get at least 50 volts by 4 to 6 thousand RPM but test each leg at a given RPM for comparison sake.

[Rikugun]

To recap, the ohm's tests (engine off) should find low and equal resistance between the stator wires, none should be grounded, none should be open.

AC stator voltage checks (engine running) should find equal voltage between all 3 wires. As a bonus, you can check from each wire to ground and hopefully find no pixie movement. This is a follow-up to checking resistance to ground except there is considerably more voltage in the wires then the testing meter's battery can provide. This is important when considering a stator that's been cooked to some degree. The wire's insulation may be viable at low voltage but begin to fail as voltage increases. For triple extra bonus points, do these tests when the engine is hot. A compromised stator may test OK with an ohm check when cool but show sigs of failure when tested dynamically when hot.

My guess (and hope) is that the stator is good but you need to rule it (and the battery) out as potential problems since there is no good way to definitively check the R/R using resistance checks. I've found a more reliable method is to eliminate the battery and stator as potential causes since those tests more often provide reliable results. These tests are approachable for many home mechanics. For the battery, it's good and equal PH for all the cells and good voltage statically and under load. For the stator, it's the tests outlined above. Provided the battery and stator test good and you still don't get nominally 14 volts at the battery while running, the R/R is probably the culprit.

[steveotmc]

Why else would I have lost the headlight bulb (three actually after wintertime this year... And it wasn't from improper installation) and why else would my sealed battery (it was AGM) nearly pop its top after highway cruising? The only thing that baffles me is that the bike started up after a few hours.

[turbosteve84]

From personal experience...

Hock whatever you need to hock, take out a loan, or rob a 7/11 and buy a Series R/R. Cheaper than buying an R/R AND a new stator (but make sure your stator is good before popping in the Series R/R).

Super hot battery? Common with a R/R failure. If you had a lead-acid battery the fluid would just boil off and you'd be left with a dry battery. Never had an AGM battery so can't speak to that. Lithium/Ion battery? Look up LI battery explosions.

Suzuki air-cooled fours of the '80s had the same charging problems as the Vision. The last time my XN85 Turbo R/R failed I was fortunate enough to be at my local motorcycle shop. They diagnosed the bad R/R and told me to remove the headlight bulb and ride home (where I had a replacement R/R waiting). Why? Twofold: to keep it from blowing and to reduce the draw on the battery.

Again, these are relatively unscientific, personal experiences. But checking the R/R and stator with a multi-meter is a simple task that even I can do. Here's my last piece of advice: DO NOT under any circumstances ride the bike with the suspect R/R. Take the time to run the tests.

Oh wait! HERE"S my last piece of advice: install a volt meter on the bike. Then you can monitor voltage while riding (or better yet, BEFORE every ride). They're cheap and in the long run will save you a lot of heartache and hard-earned cash.

Steve

[Rikugun]

+1 on adding a volt gage. Two ways to do it - use a relay and connect it to a red wire to read battery voltage or connect directly to any brown wire to read switched system power. Note the latter will read lower than battery voltage but it's switched so no relay is required. Learn and note the difference so you know when things are "normal" based on the meter's indication.

I'd say the bike was over charging. This is not as common as under charging but does happen. To illustrate the fffect of excessive voltage and bulb life consider Honda XR's of a certain vintage. They had no regulator or battery but did have a headlight and tail light powered by a lighting coil. When they came in for their initial service you could tell which ones had been ridden especially hard and in particular at sustained and higher then recommended engine speeds due to the fact the bulbs were blown. At moderate engine speeds, the lighting coils output would not blow the bulbs. Later models came with a rudimentary regulator.

Are the bulbs halogen type? If so, they must be cleaned after handling as the oils from your skin are sufficient to overheat them and cause them to burn out. Since the battery was also showing signs of an over charging condition, I'd bet on that scenario rather than dirty bulbs.

[steveotmc]

I do have a voltage gauge, but I was hoping to use the part I had so as to not let it go to waste but from my limited reading it does seem to be worth acquiring a better one so as to not have to continually acquire RRs and batteries and stators etc. Any idea (other than ebay/Craig's list) where I can find a series (or mosfet I've read, are they the same?) RR?

As far as testing goes, I do have the Haynes downloaded so I should be able to figure it out from there, but thank you for the advice and instruction it's just without the bike in front of me it's kinda hard to visualize I guess. But soon I'll be with it and be testing away, I will post updates.

[fret not]

I recall several postings by Tiger where he emphasized cleaning all the metal wire connectors so they are shiny bright and then using dielectric grease in them.  One of the main indications of faulty connections is melting connector blocks due to corrosion between the two metal parts making the connection.  If the metal wire connectors are corroded they cause resistance which causes the heat to melt the plastic connector blocks.  So, the problem is possibly the wire connections.  This may have fried the RR unit.

[QBS]

Long ago I looked at the metal male and female components in the RR to stator connector.  They appeared to be of dissimilar materials, possibly aluminium and brass.  I concluded that what might be happening is that the dissimilarity is fostering galvanic corrosion and thus destroying the connector.  My fix was to hard wire the connection.  Future disconnection needs would require clipping the separate connections.  Been operating my '83 in this manner for approx. 30 years.  I'm pretty sure that this situation is the result of another Yamaha factory defect along the same lines as the selection of the starter motor with it's inappropriate oil seal design.

[motoracer8]

My 2 cents worth. I believe the contacts in the connector between the RR and stator are not heavy enough for the job, and just alittle corrosion or oxidation in that connector creates resistance heat and failure. I replaced the stator and regulator with OE Yamaha parts 25 years ago and added heavier separate connectors and have had no issues since.