Dimmed headlight at idle and brighter with revs

[Kristis]

Hi all,

Is this normal that on idle Fz6 has dimmer lights and getting brighter with revs? My Ducati and BMW don't have such thing, so I'm wondering if anything is starting to go bad (stator?) or is this just normal? Bike runs fine, no probs with that except light brightness which gets irritating when at night...

 

[ShoopCE]

Hello Kristis,

The electrical wizards will soon reply, but in the meantime, I'll make some suggestions.

The behavior of the lights getting dimmer on idle and brighter as you increase rpms is an indicator for a battery problem. The battery voltage is low and the bike isn't producing sufficient current at the lower rpm's. It could be the battery is failing. Or it could be that the connections at the battery need to be cleaned - which would keep the battery from getting a full charge. Or it could be the stator or the regulator/rectifier which if they fail will not provide sufficient current to charge the battery..

The first step is to check and clean the terminals at the battery. This is simple and inexpensive, but does not have high probability of fixing the issue. Take the bike on an hour long ride.

If the lights still go dim while idling, remove the battery and have an auto shop test it. If you have a trickle charger, then fully charge the battery before the test. The results are more accurate.

If the battery tests as "good" or even "OK" then you probably have a problem with the charging system.

Last fall/winter my stator went bad. It eventually shorted to ground and produced almost no current.

Take the bike to a shop. Or if you like to do it yourself, get a Haynes manual and a decent multimeter. I had a very very inexpensive one that did not help me find the problem. I bought a better meter ($30) and then the problem was easy to find.

The process of replacing the stator is simple.


Regarding the headlights, if you want brighter lights, consider upgrading to LEDs. I used these:

https://www.amazon.com/Auxbeam-Head...DFQVF9H3AZM&psc=1&refRID=SYQ9V6G9HDFQVF9H3AZM

The Auxbeam NF-S1 series worked great for me. They use a heat sink rather than a fan for cooling. They are extremely bright and have a well focused beam. Many on here are leery of LEDs because they tried the earlier versions that did not form a well focused beam and consequently they would annoy/blind oncoming drivers. You need an H4 and an H7. The Amazon site only offers these in pairs so you end up with a spare set or you can share them with a friend who has an FZ6. One of the bulbs fits in easily. The other one (left side) takes some adjustments. The Yamaha installation used an adaptor to connect the bulb to the wiring harness. That adaptor also served as the surface that is held in place in the headlight reflector mounting by the clip. you will have to connect the adaptor to the end of the heatsink where it will not be useful for the mounting clip. I used a nylon washer on the shaft of the bulb. This has stayed in place for a bit over a year now. Noting melted. This was not the cause of my stator failure.

Good luck,
Chris

 

[Motogiro]

It is normal to see a slight difference as you go from idle to above idle on the FZ6. You can check your voltage to see that it's within normal range for idle to above 2000 rpm. Key off voltage at the battery should be 12.6 to 13.0 vdc when the battery is fully charged.

Here is a link to Charging system and Battery trouble shooting.https://www.600riders.com/forum/fz6...ttery-charging-brake-bleeding.html#post579412

As you can see voltage variation can be enough to show a difference in brightness on the headlamps. Variation on different make, model and headlights can make a difference in what you experience.

 

[TownsendsFJR1300]

I dare say it's not normal..

I also have the BD43, dual headlight mod (two head lights on at all times), higher output PIAAs and keep my idle low at about 1,100 RPMs.

I do not have any fluctuation at idle and that's also with the battery needing replacement..

As noted above, I'd check the electrical system to find what's weak..

 

[Kristis]

Thanks guys for help! Went through everything and i'm thinking there is a phantom drain somewhere most likely. Battery is a new lithium one and tested the stator running - turned out ok. WIll try to go through all wires and see

 

[bigborer]

You are correct with the "phantom drain"- it's actually extra resistance due to oxidation at the connectors.

MOST electrical problems are caused either by oxidized connectors or failed insulation. 95% of it being just oxidized connectors, at least on Japanese bikes. Maybe on an older Italian or British (junk) you might expect to find lots of failed insulation.

Sometimes it takes a lot of oxidation, other times only a barely visible layer.

On my FZ6 almost everything single connector was oxidized. This lead to dimming, no brake light, no turn signal light, and at some point no position light and no low beam.
On other bikes I had temperature issues due to corroded temp sensors, fan and thermostat connectors.
On a car I had a strange stutter at certain rpm due to the ignition coil connectors.
And other examples which I don't have the time to type right now.

To resolve all the above I only used contact cleaner spray (any random brand will work), then carefully (wouldn't want to bend anything) scraped the metal with a thin flat screwdriver for the more severe cases, then applied some battery terminal grease - any random brand will work (it's actually dielectric grease) on the metal blades of the connectors. Be very careful to apply ONLY a thin layer as small as needed to barely cover the metal parts- too much grease overflowing will likely cause an short circuit.

For the lighting system I'd recommend that you clean and grease:

1-the battery terminals and connectors- here you could also scrape a bit with some sandpaper
2-the voltage rectifier connector- it's the black metal thing with cooling fins located under the seat, the connector is on the left
3-the headlight relay- located in the left side on the tail
4- the headlight fuse- located in the right side of the tail
5- the headlight subwire harness- it's located in front of the battery, in a black protective rubber booth. You need at least to take out to battery and battery case, if not also the air filter, for this one
6-the plugs that connect directly to the bulbs

For #3 and #4 it'd be a pity if you didn't spend an extra 10 minutes and just cleaned and greased EVERY single connector in those areas.

Do this first and only AFTER you might think about a defective battery or rectifier.

 

[Motogiro]

I had a brand new FZ6 from the dealer. Never had an electrical issue with the bike and that includes never having to replace the battery for the time I owned the bike. I used to see the slight change brightness from idle to above idle.
When an incandescent lamp sees a change in voltage you may see a change in brightness going from idle to above idle. Depending on what manufacturer engineering design. Crossection of wire, purity of copper, voltage drop at plugs, rectifier/regulator and stator efficiency all play a part.
You can see a slight variation in brightness that does not mean there is a failure.

When looking for parasitic drain there is a process that should be observed when doing the test and if the process is not observed you will see what seems to be a parasitic when in fact the system is in healthy condition.

 

[TownsendsFJR1300]

I used to see the slight change brightness from idle to above idle.
When an incandescent lamp sees a change in voltage you may see a change in brightness going from idle to above idle. Depending on what manufacturer engineering design. Crossection of wire, purity of copper, voltage drop at plugs, rectifier/regulator and stator efficiency all play a part.
You can see a slight variation in brightness that does not mean there is a failure.
.

^^ That may be, with the PIAA bulbs, why I never saw a change in the output.

With that said, EVERY electrical plug I come across gets a dab of dielectric grease in them... I never had any electrical issues, short of normal battery replacement..