Voltage Drop at Idle

[XSSIVEUS]

Have a 78 1100E that runs great, maintains charge, fires right up, etc. Issue is that when I come to a stoplight and the turn signal is on, it slows down and then stops flashing. I have a fairing on this bike with a voltage gauge and it shows the voltage dropping at stop/idle.

When riding the voltage is around 12-14 volts. At idle it drops to 8-10, less with turn signal. The gauge hasn't been calibrated in years, but comparatively it's probably a decent approximation. I replaced the flasher unit early this year during a restoration with a NOS unit.

Is this a regulator issue, corroded contact issue, defective flasher unit, or something else?

Thx

[jetmechmarty]

I have the same issue. My bike also runs rich and is low on power. The spark is weak.

Your bike is 40 years old. The likely culprit is corrosion. Yamaha did not intend for you to keep a motorcycle for 40 years. Wire is made of copper. The Statue of Liberty is made of copper. She's green. Your wiring may be getting there, too.

I may decide to build a new main wiring harness, since I have the tools and necessary skill to do it. Just no time right now. Every connector, pin, and wire color is available at http://XJ4Ever.com. http://www.sparckmoto.com is another source.

A while back, I found corrosion removal options via Google. I have not yet tried it.
https://www.instructables.com/id/How...es-in-minutes/
https://youtu.be/TfEIEVrmzVw
Some time ago I found a YouTube about removing corrosion from the wiring of an old car. They disassembled the plugs and the same salt/vinegar process worked well on the pins.

I don't recommend dielectric grease, but you'll find plenty of dissenting opinion on that.

Best wishes!

[jetmechmarty]

The first thing to do is remove the right side cover and the panel that the fuse box is mounted on. Behind it is the connector to the stator. Make sure that one is clean and conducting. Lose that one and it will take the stator with it. You'll know right away if it's bad. The plastic will be brown or melting.

[DiverRay]

An easy first try is remove all the ground wires, clean them and the frame contact point, then re-assemble with some anti-seize smeared around the frame and connectors. Don't forget about the engine to frame ground, as it may be the big problem. This connects from the middle drive to the frame just behind the Left side cover.

[motoman]

STOP/RUN switch internal contacts are a common issue creating a voltage drop. This switch COMPLETES the running circuit. I suggest unplugging it and remove it from bars, take apart and clean contacts by dropping switch assembly in a shot glass full of Evapo-Rust. Afer a couple hours, remove it, rinse with water and blow dry with compressed air. Re-assemble,plug back in together and re-mount on bars. After doing so, internal contacts of switch WILL look like new again as will the switch assembly itself.

[XSSIVEUS]

All good ideas. Will work through all until the gremlin is found. Thanks guys!

[skids]

All good ideas. Will work through all until the gremlin is found. Thanks guys!

Keep in mind also that break even for charging is something like 1800 rpms, Below that at you are running off the battery — which can discharge steadily with the brake light on, the headlight on etc... One of the most inportant grounds is the frame/volt regulator mount.

[XSSIVEUS]

Also a good idea. Thank you Sid!

[Schming]

Reg/Rec

Along with all the above suggestions, cleaning and so forth, the absolute best mod for these bikes is from one of our members "Geezer"

This link takes you to his site :
http://www.oregonmotorcycleparts.com/Reg_rec_units.html

He makes aftermarket Reg/Rec's for a host of MC's that will end the discharging of the battery at idle.

I'm going to assume that Your "E" is the one in the avatar, if so, I have a Pacifico fairing on my "G" also and a trunk with two brake lights and since I installed Geezer's Reg/Rec I no longer have to rev the engine to get the turns to flash at red lights

Also I have replaced the stock bulbs with LED's where possible.

HTH

[XSSIVEUS]

Interesting idea. I'll read up on it. Thanks!:

[MPittma100]

Battery Ground

Do the bike and yourself a favor and improve the (poor) chassis grounds to direct battery grounds. You can achieve this by linking all of the chassis ground points with jumpers so as they all are directly connected to the battery ground terminal. A good chassis ground is a poor ground at best and causes the burned terminal pins due to high resistance.

The amperage output of these alternators is quite low. The electrics on the bike draw most of the amps away and the alternator just barely keeps up with the load. The Geezer upgrade helps. Replacing the incandescent bulbs with LEDS gives the alternator much needed breathing room.

[XSSIVEUS]

Good advice Mike and will see how best to do so, thx.

[MPittma100]

Ground

Good advice Mike and will see how best to do so, thx.

Former ground conversation:

http://www.xs11.com/forum/showthread...attery+grounds

The engine idle speed when warmed up should be 1100 RPM. Anything lower tends to drain the battery more.

[TopCatGr58]

Hey there,

Just be aware that when trying to replace the TURN SIGNAL lights with LEDS, that you will most likely need to change to an electronic NO LOAD 2 PRONG flasher designed to handle LEDS. Messing with resistors and such defeats the purpose of using LEDS. The 2 prong flasher will go 1 of 2 ways into the plug, will work only 1 way. You will loose the SELF CANCEL feature though. There is/was a tech tip or post about a MOD to be able to keep self cancel feature with LEDS, you can search if so inclined, most folks don't bother using the self cancel anyways, just push the turn signal button straight in to turn off.

The stock Alt is rated at ~25 AMPS Max. The ignition system is fused for 10, but probably runs at 5-7, noboby's ever posted an exact figure for the TCI and the ignition coils. The headlight 55W=4.5amps, brake light 27 watts=2.25 amps, turn signals 27 watts x 2= 4.5 amps, gauge lights 8 watts x 4=2.5 amps, THEN you add additional running lights/trunk, and you can see how you can run out of available amps/watts with the charging system.

T.C.

[donebysunday]

T.C.'s fuse block

No one mentioned the spade fuse block conversion from T.C., great upgrade.

Also going through each and every ground and power connection, cleaning, squeezing the female if not tight, cleaning the bulb sockets and the use of dielectric grease on all to help keep the connection from oxidation in the near future.

The battery itself, good, if lead acid, is it full of distilled electrically charged water ?
If you need to top it off to full wait to check at full charge, if you check right after filling it will read low.

Anti-sieze I never heard of before on the grounds ? Is it as good, better than dielectric grease ?

Check the amount of battery charge disconnected, 12-12.3v give or take a little and charge rate shown on the battery when running 1100-2000-2500-3000 rpm., by 3000 if you don't have 14v +- check connections again from the alternator, re-test. Still no ?, time for Andreas.

Please correct me if wrong !

Please excuse me if I missed the mentioning of these things previously !