when brakes are applied the headlight dims

Ever since I have owned my xj700x the headlight dims when I apply the front or rear brakes.
I have checked the out put of the generator and it is 14 volts + .
Any ideas?

 

When you apply the brakes your brake light buld illuminates depending if you have correct bulb this puts a slight draw on your electrical system. How dim does it go ? If you rev engine up does your headlight get slightly brighter? If so your charging system works.

 

My XJ550 slightly dims at idle and brake lights come on until I rev the engine. Done this since day one when it was brand new.

 

go to led bulbs for the tail and brake lights.
when you apply the brakes you are slowing the motor or by pulling in the clutch letting it return to idle rpm lowering the voltage output.
current draw changes as the voltage changes.
are you getting 14.8 volts at 3000 rpm?

spec 3000+ rpms: 14.2 volts up to about 14.8 volts, with a maximum of 14.8 volts (all XJ700-X and XJ750-X)

inspect the brushes and copper rings clean them
you could inspect the connections on battery and all the ground connections to battery frame motor ant the ring terminals at coils make sure they are clean.
voltage regulator connector coulld be dirty

check the headlight connections
any dirty connections add resistance to the circuit. you may also want to clean the starter button if the xj700X controler is like the xj750 controler the head light is run off of the starter button with no relay. starter button out headlight on.

when I press the horn button my headlight dims.

 

Grab a can of electrical contact cleaner/ deoxidizer, and a tube of dielectric grease. Go through the whole harness and clean, then grease, then reassemble.

 

What k-moe says. I cleaned all my connections for a different reason, but I did notice a significant improvement in how much the headlight dimmed when breaking. I was concerned before, now i'm not.

 

Purchase a headlight relay harness, all of your problems will be solved the right way!

HEADLIGHT RELAY-CONTROLLED WIRING HARNESS:

Headlight Relay Wire Harnesses:

In order to take full advantage of either stock or aftermarket headlights, full battery voltage must be available at the headlight terminals. The long run of under-sized factory wiring, and the stock headlight toggle switch, will not allow your headlight to receive a full dose of current, and thus your headlight---the most critical safety component on your bike----will be suffocated for amperage and will far less brighter than it should be. The solution is a professionally assembled, plug-and-play RELAY-CONTROLLED HEADLIGHT HARNESS that uses your headlight switch to actuate an electrical switch (the relay), which then allows full battery power to your headlight.....allowing it to shine like the sun!

REMEMBER, as per the discussion previously, that headlights are rated at 12.8 volts, but typically receive a lot less......and that's the main reason why your headlight is so dim.

These headlight relay wire harnesses are simple to install-----even for the most electrically-challenged mechanics-----and come with extra terminals, cable ties, instructions, and do not require cutting your original wiring harness at all. Your stock headlight switch now powers the relays, rather than the headlight, and thus no new switch is needed. Installation time varies, but normally requires 30 minutes or less to install (mostly involving the removal and replacement of your seat and gas tank, and the routing of the wire harness), and absolutely no soldering is required.


HCP14749 Aftermarket headlight RELAY-CONTROLLED HEADLIGHT HARNESS, with plastic headlight socket.
$

HEADLIGHTS:

Let there be Light!.........

Enough of it, that is. Motorcycles, suffering from only having a single headlight, tend to have woefully inadequate lighting for night-time driving, especially on unfamiliar roads or during "spirited" riding. We're going to try to help you understand why, and then offer you a variety of solutions. Here goes............

What most people call a "headlight" is really three separate functional components: the glass LENSE, a highly polished REFLECTOR, and the electrically operated light-producing BULB.

In some cases, the glass LENSE and the polished REFLECTOR are formed and molded as one unit, and are inseparable from each other. On other models (primarily with the square lights, such as the XJ750 Seca models, etc.), the reflector is actually a metal housing with a non-removable (unless you try really hard!) flat front glass lense.

Additionally, some bikes (XJ550 models and XJ650 Maxim and Midnight Maxim models) are factory-supplied with a SEALED-BEAM type of headlight, where the bulb is part-and-parcel of the lense and reflector assembly, and not removable nor replaceable. All other XJ models use a MODULAR headlight system, which means that the bulb CAN be removed from the lense/reflector unit....and thus if the bulb burns out (or an upgraded wattage or style of bulb is desired), then only the bulb needs to be replaced; the glass lense and reflector unit lives on, basically forever.

Although most people feel that the BULB is greatest determinant of a headlight's light output, this isn't really the case. Although sealed-beam headlights and modular bulbs are available in a variety of wattage ratings, the amount of USABLE LIGHT (meaning: "how much?" and, especially, "where?") are controlled as much by the LENSE and REFLECTOR DESIGN as by the bulb's rated wattage.....

And lets talk about those rated wattages for a moment, because that's an important issue: all automotive bulbs are rated for a certain current draw (which translates somewhat nicely into "light output", although it is really not a one-to-one relationship) of 12.8 volts DC. But are you actually getting 12.8 volts DC (VDC) at your headlight? Probably not....and if you want to check for yourself, hook up a voltmeter and read the voltage drops while the engine is running at various speeds. Do you get 12.8 VDC (or above)? Probably not. And that's where the problems begin.........

http://www.motorcycleproject.com/text/volt_drop_test.html

and here’s an easy-to-understand guide to how to perform a voltage-drop test:

http://www.agcoauto.com/content/news/p2_articleid/330


Because the reduction in voltage available to the headlight reduces the light output from the "advertised" or rated level rather quickly......i.e. a 10% voltage drop gets you about a 33% reduction in light output (yes, you read that correctly, a 33% reduction, whoa!).

This is why the condition of your wiring system is so critical to proper lighting. But that's only part "A" of the story............

Here's part B: your glass LENSE. Whatever amount of light your BULB is outputting---dependent upon the bulb's wattage rating and the capability of your electrical system, as outlined above----the "how much?" of the available bulb output and, more importantly, the "where?" of that light output is controlled by the lense.

You see all those raised ribs (called "fluting") on the glass lense? The light comes from the bulb, then it bounces off the reflector, and is then finally concentrated or diffused ("spread out") according to what and how that lens fluting has been designed. The fluting can be designed to give a broad, spread out pattern of light, and perhaps with a narrow, focused "pencil beam" of the available light output all going straight ahead----or anywhere in-between. Reflector and fluting design elements are what really make the difference between "standard", run-of-the-mill headlights and high-performance headlight manufacturers (such as Cibie, Hella, Marchal, etc.)....after all, a 55/60W bulb is basically going to output the same amount of light whether it's installed in a No-Name brand headlight lense/reflector, or whether it's installed in a Hella Euro Vision Plus headlight. It's what the headlight lense/reflector DESIGN does with that available light that determines whether, or how far away, you see that deer that is about to jump out into the road in front of you......or not.

There, you're almost an optical expert. You can now hopefully make a better, informed decision as to what you want and need, and how much that is worth to you.

Let's now review the standard headlights that came on these bikes:

All XJ550 and XJ650 Maxim and Midnight Maxim models used a 7" round SEALED-BEAM headlight with an integrated bulb-reflector-lense assembly and a non-replaceable bulb. These stock bulbs are rated at 40W low beam and 50W high beam current draw. This is basically 1940's technology and about the worst headlight performance you could ever imagine, just one step above using a candle in place of the electrical bulb. The good news here is that you can upgrade these headlights to a slightly higher wattage modern sealed-beam bulb (35W low-beam, 60W high-beam) or just completely ditch the sealed beam and go with a modular headlight system.

All XJ650RJ Seca, XJ650 Euro models, and XJ900N models used a big, beautiful 8" round modular headlight. I really love the way this slightly over-sized headlight makes these bikes look so much more "old-school aggressive". The good news is that it takes a regular, easily-located replacement bulb; the bad news is, if the lense/reflector assembly is cracked or damaged in any way, you're going to look long and really hard to find a replacement, since no one seems to be making 8" round headlight units anymore. Stock bulb rating is 55W low beam, 60W high beam.

The XJ650 Turbo, the 1982 XJ750 Maxim, all XJ750 Seca models, and the XJ900RK, RL, FN, and F models all used a rectangular, modular headlight system, with an easy-to-find and replace bulb. Again, the stock bulb rating is 55W low beam, 60W high beam.

The 1983 XJ750 Maxim and Midnight Maxim models, as well as the XJ1100 models, used a 7" round modular headlight system. Bulbs and lense units alike are easy to locate. Like all the other modular headlights, the stock bulb rating is 55W low beam, 60W high beam.

Next, all the XJ700 and XJ750-X models used a smaller 5-3/4" round modular headlight system. The bulb is rated at the tried-and-true 55W low beam, 60W high beam.

Finally, the XJ750 Seca and 1982 XJ750 Maxim models used a smaller, rectangular "driving light" below the main headlight, and this too is a modular designed light, with a replaceable bulb, although the bulb used in these lights are only a 35W output from the factory, and are a different style bulb than the headlight uses. Bulbs are readily available for these driving lights.

So there you have it.

Now, a couple of question always arise, the first always being:

Q1) Should I upgrade to a much higher wattage BULB?

A1) In a nutshell, NO. The problem is not the bulb's light output, it's the compromised electrical system on these bikes that restricts the voltage available to the bulb that is mainly responsible for the poor lighting, along with the somewhat poor design of standard factory or low-cost aftermarket headlight lense/reflector units.


Q2) How to I remedy the "compromised electrical system" on my bike?

A2) First, make sure that ALL---meaning every last one---of the electrical connections in your headlight system are clean and un-corroded.

This means starting from the fusebox forward---and while you're at, replace your stock fusebox, as it's usually a huge source of electrical resistance in your system (more resistance = less voltage across the connection).

This also means the contacts inside your left side handlebar switch should be squeaky clean (electrically-speaking), gunk-and-corrosion free. You'll have to take apart your switch and clean all the contacts internally, which isn't a bad idea to do anyway.

And of course, make sure that your battery and your alternator (those brushes) are in great shape, and actually capable of outputting the proper voltage into your electrical system to begin with.


Q3) Why don't I just install a higher wattage bulb, even with a compromised, ritually-unclean electrical system?

A3) Because it doesn't work that way. I would suggest reading Section 8 on this excellent article about XJ electrical systems (heck, you should actually memorize the whole article) and you'll begin to see how "going bigger" is not only NOT better, but could be a whole lot worse, economically and otherwise:

http://web.archive.org/web/20071214...ies.com/MotorCity/Speedway/7795/xjfaqbig.html


Q4) Should I use the "whiter" or "daylight" or "blue" or "purple" or "whatever" modular bulbs that are advertised as producing "better light" or "whiter light" or "more light" or "bigger light" or blah-blah-blah?

A4) You can, but it's mostly hooey that you're buying. Again, the problem isn't the light output of the BULB, it's the electrical system and the design of the reflector and lense that are the real issues. A great in-depth, easy-to-understand review of these issues can be found at:

http://www.danielsternlighting.com

Go and read the "TECH" section of the website "bulb articles". You might be in for a surprise.........but at least you'll know the truth, and that's supposed to set you free.


Q5) So what do I do?

A5) First: make sure your electrical system is in tip-top shape: alternator, battery wiring, connectors, switches should all be operating properly and all of your the connectors are going to have to be cleaned. This is cheap but time-consuming to do.....but, it produces the best results. Like love, there's some things that money just can't buy.........

Even better, update your headlight system to modern standards by using our easy-to-install HEADLIGHT RELAY HARNESS that allows you to pump pure, fresh, full battery voltage directly to your headlight.....the way nature intended it to be!

 

Yes when I rev or accelerate the dimness goes away.