Technical Tips – Page 2 – Airheads Beemer Club

Running Lights on a /6

I originally wrote this piece some seven years ago in 1995. Finding that the last of my modified bulbs burned out one filament the other day, I had to make some more up, which gave me an opportunity to revisit the article and to make it more useable.

Note that most if not all states require that any taillight or running light on the rear of a vehicle be RED as per D.O.T. guidelines unless it is used to illuminate the license plate.

The idea is to increase visibility of a motorcycle by the addition of two permanently illuminated rear running lights. Added to the central red light this gives three rear facing lights, allowing car drivers to triangulate on three light sources rather than one, enhancing their depth perception and improving the biker’s safety

I had fitted Full Scale Designs’ running light kit to the front and rear of my K100LT. A nice installation on a not so nice motorcycle, now sold and unlamented. The installation described here is not as elegant as FSD’s but is equally effective. It has the merit of being much cheaper. You can also buy a ready made kit from www.run-n-lites.com for $30 plus a $50 core charge (as of August 2002). I cannot find a listing for FSD.

You must be a member to view complete articles on this website. If you are already a member, you can log in here. If you aren’t a member yet, you can purchase a membership here.

Headlight modulators

Headlight modulators are, or can be controversial, with differing viewpoints & arguments for & against. Some find modulators annoying. I believe that is, perhaps not always, folks seeing OTHER folks’ modulators, not their own. Some are concerned about oncoming drivers fixating on one’s modulating headlight & aiming for them, this seems to come from the idea that a motorcyclist tends to ride to wherever they fixate on. Studies have shown that adding lights at the rear (& in some instances the sides) of motorcycles makes them more visible and recognized earlier. For the rear, the lights should be red & as differentiated as possible between Run & Brake. Bright clothing, greenish-yellowish helmets, etc. …all have been shown to reduce accidents. I see no one arguing about ‘fixating’ on THEM.

Whether or not to install a headlight modulator on YOUR bike, is a personal choice; the USA government has not made them mandatory. My comments in this article apply to the USA, as headlight modulators may not be legal in some other Countries.

There ARE reasons that motorcycles are specified, since 1978 in California, & specified in many other States, to automatically, upon ignition turn-on, to power headlights ON, without having to manually turn the headlight(s) on. State law & Federal law are not necessarily the same thing, but, typically, Federal law supersedes. In this instance, always on headlights after a certain year model does apply. There is also an argument about certain cars, such as late models, having constant-on headlights …the argument usually is negative, as motorcyclists want only themselves to have such lights, to differentiate between them and cars. That’s a decent argument, but tends to favor modulators in use during the daytime.

You must be a member to view complete articles on this website. If you are already a member, you can log in here. If you aren’t a member yet, you can purchase a membership here.

Adding Running Lamp To Turn Signals

This article deals specifically with converting the two Airhead rear turn signals into running lamps, while retaining the original turn signal function. Considerable information is applicable to a FRONT turn signal lamps conversion, if desired.

This article does not deal directly with conversions to the Classic K-bikes, such as the K1, K75, K100, K1100. MUCH of what is in this article on the physical modifications ARE applicable to K bikes, Oilheads, ETC. The K-bikes have a bulb-monitoring relay; which complicates matters, & information on modifying them is in item #2 in http://bmwmotorcycletech.info/K-hints.htm.

Adding running lamp functions to the rear (and/or front) MAY add to safety. You get more lights, & you have two lights that are illuminated in case your one rear stock running lamp burns out; many bikes have only ONE rear running light & if it fails you might be INVISIBLE to cars coming up towards your rear; which is one of the arguments FOR this conversion. My primary argument against this conversion is that the turn function is, or can be, less noticeable to car drivers ….due to the running lamp function in the same lamp, same housing (could be separate lamps on fronts, some bikes). You must decide for yourself. Proper installation with proper color of lens & proper lamp bulb may negate such arguments.

The conversion may not be legal in some States, ….if the lens is not re-colored to be RED (or the lamp colored red). Careful selection of bulb & possibly inclusion of reflective aluminum foil may improve brightness.

There are potential problems if not done well, the turn signals might then not be as distinctly different from the running lamp function. Properly done they certainly CAN be very distinctly different. Several ways to go about it, including a small unpainted or no red insert area, in the middle of the lens, or, a band across the center. One can find red bulbs plus use aluminum foil as a reflector, if desirable. The reflectors & lenses of the stock bike are OPTIMIZED for incandescent lamps, NOT LED types. I do NOT recommend LED lamps (of any type I have so far seen) for purposes of this article although wide angle LED lamp structures may now be available. RED LENSES have been available at times, almost a perfect direct replacement for your amber ones; you need only to provide a rubber gasket (easy and only if you wish to), and in a few instances about a minute of filing, depending on if plastic or metal case. The ones I have seen have an even better than stock amber lens light diffusion/reflection in the lens. Check such as Ebay. The ones I saw have number K22750 and K32724 on the plastic cover & were made by CoolBeam MTP; they are marked as SAE & DOT approved. These are hard to find in the USA. I have a set on my bike. If you find a source, PLEASE let me know so I can publish it here.

The conversions in this article are for incandescent lamps. You are free to experiment with plug-in LED lamps, but I have not done much experimentation so far.

You must be a member to view complete articles on this website. If you are already a member, you can log in here. If you aren’t a member yet, you can purchase a membership here.

Accessing the Headlight Bucket

The fairing-equipped Airheads began with the 1977 R100RS. The headlight bucket is basically the same as in the unfaired models (except for later models not having fuses, etc., in the bucket). The bucket is not part of the fairing. On the RS and RT the bucket is located behind the front-most protective glass that is part of a ‘tunnel’ assembly with a large protective rubber molding with an outer glass, etc., whose design is such that it offers a relatively smooth front surface to oncoming wind, etc. The expensive outer glass has some orange lines on it. There is no purpose to those lines (stories abound, all wrong) except to draw the eye away from the quite large front glass. While the orange lines were purposely installed for that stylish effect, the headlight/bucket was quite far inwards from the front of the fairing, and thus the outer fairing tunnel glass needed to be of substantial size to prevent narrowing of the headlight beam. There is no aiming or other purpose to the orange lines.

Don’t do any disassembly of the fairing beyond what is noted below, unless you have a good reason to do so!

1. Fold back, barely (just a small amount), one corner at a time, each corner of the rubberized material surrounding the $$$ glass in the fairing. That will just barely expose a phillips screw at each corner.

You must be a member to view complete articles on this website. If you are already a member, you can log in here. If you aren’t a member yet, you can purchase a membership here.

Recognition & Safety

Conspicuity …Recognition …Safety ….

This article deals primarily with improving recognition and speed of recognition…hopefully leading to action by drivers of ONCOMING vehicles (whether from your front, rear, or sides), but also covers how YOU see other vehicles.

Many safety agencies …and studies, …have proven that safety is enhanced for motorcyclists having modulated headlights …as the pulsing light attracts attention, particularly important to a motorcyclist, who wants, or should want, an oncoming driver to notice & recognize that a motorcycle is there. This has been shown to reduce left-turn accidents, & in general, reduce most biking accidents.

Studies have also proven that bright clothing and certain colors of helmets help reduce accidents considerably.

State and Federal Governments testing and reports is NOT extensive for motorcycles, nor is private/commercial testing/reports. While many effects do cross-over between carts and trucks and motorcycles, the information is spotty about specifics for motorcyclists. Further, there is a considerable amount of wrong ‘information’ in common use or understanding. Especially notable is the paucity of knowledgeable effects of movement and head positioning of drivers/riders of vehicles on recognition times; although there are other things, including lighting, colors, etc….and these are vast subjects. Many of the technical details are in this article: http://bmwmotorcycletech.info/hdlite.htm
The information in that article is extensive. I HIGHLY suggest you stop here, and read that ENTIRE article, before proceeding!

You must be a member to view complete articles on this website. If you are already a member, you can log in here. If you aren’t a member yet, you can purchase a membership here.

Tachometer, Speedometer, and Odometer Calibration

BMW odometers tend to be quite accurate, and all the speedometers EXCEPT the 85 mph ones (which are usually accurate), tend to read high by 6 to 12%. This is ON PURPOSE by BMW. See the article hyperlinked just below, which is more detailed and has the information on why the inaccuracy, and MUCH more.

Recalibrating a speedometer is a touchy job, of messing with such as hairsprings, and is best left to an expert.

Speedometers/odometers have W ratios printed on the face, and they must correspond to the rear drive ratio, see the charts on the author’s website, which is more expanded than on this airheads.org website. The following hyperlink to the author’s website has all the information you would want:

You must be a member to view complete articles on this website. If you are already a member, you can log in here. If you aren’t a member yet, you can purchase a membership here.

Speedometer Repair

Thanks to all esp. Paul Glaves, Jeff Saline, and Randy Mallon

After some probing I found the upper RT silver gear that transfers drive from the total mileage to the trip odometer to be loose on the shaft and causing the trip odo to run intermittently. Using minimalist approach and a tooth pick I first carefully dipped the toothpick in alcohol and cleaned the shaft without disassembly. Steady hands and a watchmakers magnifying loupe helped. When that dried I put a drop of liquid crazy glue an a piece of plastic and using a toothpick I dipped it in glue and than transferred small amount to the shaft above the gear keeping it upright so capillary action will draw it downwards. I am now considering a good spot to drill a 1/4 inch hole and put a Gortex patch over it to try to get rid of fogging.

Jeff Saline cautions: One thing I don’t remembering anyone commenting on is allowing super glue the opportunity to out gas outside of the instrument housing. I haven’t ruined a lens yet but understand that if you use super glue and immediately reassemble the instrument housing the super glue will out gas and fog the instrument housing lens(es). I was repairing a high beam indicator blue lens the other day and have had the instrument out gassing for 6 days now. I recall hearing 24 hours is enough time

You must be a member to view complete articles on this website. If you are already a member, you can log in here. If you aren’t a member yet, you can purchase a membership here.

Wiring Color Codes

This covers most of the basic wire colors used on Airheads. As the electronics got more complex, more combinations came into play so it’s possible a few of the more obscure ones may see other uses. Always double check factory wiring diagrams, and yes, even they can have a mistake or two. PowerBoxer.de has a copy of the Haynes ones. And here’s a link for more about Airhead relays and terminal designations.

You must be a member to view complete articles on this website. If you are already a member, you can log in here. If you aren’t a member yet, you can purchase a membership here.

Headlight Switches & Headlight Relays

This article was originally written (and since then, expanded/edited numerous times) because someone asked about the left-hand switch of BMW Airhead motorcycles if using higher powered headlight bulbs. He did not understand why the existing stock headlight relay would not automatically eliminate wear on the switchgear. The simplified reason is that the stock headlight relay does not do what many think it does, at least on most, especially later, Airhead models. Variances of his question have come up many times, often on the Airheads LIST, but also on various other forums, and even for other BMW models.

It is important to know that the main purpose of the stock headlight relay FROM 1978 is to turn off the headlight, leaving the dash lights and rear running lamp on, during the time the starter motor is cranking the engine. The relay turns off the headlight during cranking, and that’s all.The stock headlight relay from 1978 also does not do theswitching between high & low beams. NOTE that the high beam flasher (‘passing lamp’) function remains, due to a green wire from the ignition switch, as a separate circuit. The headlight relay may or may not turn off the headlight, during engine cranking, depending on year, model, & country shipped-to. On some Airheads, the high beam flasher button (‘passing lamp’ function) MAY be available with the ignition off. It is a matter of where the green-colored wire goes to. It is easy to move a green wire at the ignition switch, and thereby have the ignition be ON, but the headlight OFF, in the PARK function, but there is more to this, and this is not the point of this article.

Using additional relays to control higher-powered headlamps (stock is 55/60 watt) is a must; although some have gotten away with not doing so for some time. Note that the left bars switch assembly is fairly expensive. It is not designed to handle high-powered headlamps, and it would have been, …perhaps, …better if a relay had been used by BMW to handle all the current flow to the low and high beams. This is not difficult to accomplish, and such as the Eastern Beaver kit does it. With that kit installed (or, your own two relays), the bars light switch(s) would only pass current to the extra relay’s COILS. This means that using accessory relays will reduce wear on the left switchgear even with the stock headlight; and usually will increase light output slightly due to a more direct current path from the battery to the relay. This increases the headlight voltage to closer to battery voltage….another way of saying this is that a more direct power path reduces wire and some switching losses.

Sources for appropriate relays are any auto-parts store. However, www.EasternBeaver.com sells complete plug and play kits for your motorcycle, and they may even still have a version with a modulator if you wanted that.

You must be a member to view complete articles on this website. If you are already a member, you can log in here. If you aren’t a member yet, you can purchase a membership here.

Basic Electricity 101+

The below article was written to furnish THREE types of information:

(1) CONSIDERABLE amount of BASIC & SLIGHTLY ADVANCED INFORMATION on electricity & Airhead problems. The approach used here is probably different than in most manuals & troubleshooting guides. Although some hints are given in this article on some common faults, this article should be used in conjunction with my other articles, particularly: http://bmwmotorcycletech.info/electricalhints.htm

(2) Common problem areas, explanations of some of the circuitry. A discussion of such as batteries; starter motors, voltage regulators, etc. Other articles will get far deeper into these things.

(3) An addendum that may discuss particular points that has come up, or some topic of interest. Some is at the very end of this article.

Available to you are certain helpful booklets from such as Motorrad Elektrik, Chitech, Haynes and/or Clymers manuals (and, perhaps, a schematic in the rear of your owners booklet or on the Snowbum website). In my opinion the Chitech electrics manual and the owners book or factory schematic, or schematics on the Snowbum website (and some elsewhere’s, and I have links to these on the Snowbum website), are THE BEST sources for electrical information for the Airheads.

I recommend you at least purchase at the Chitech Electrics Manual. The Chitech (Chicago Region BMW Owners Assoc.) BMW Electric School Manual is THE BEST manual for BMW electrics, from basics to full-blown technical details, components, diagrams, etc., & includes the singles & all Airheads; even some on the /2 era. It is VERY complete. Only a few errors, for which i wrote an article/Critique: http://bmwmotorcycletech.info/chitechelmnl.htm

See http://bmwmotorcycletech.info/url.htm for more information on Chitech, and how to order their publication. Some of the total-bike schematics are not reproduced well, that is the only substantial problem with that manual. Get the manual anyway.

You must be a member to view complete articles on this website. If you are already a member, you can log in here. If you aren’t a member yet, you can purchase a membership here.

1 2 3 4 5 … 10 11 12

Posts navigation