airhead electrics, help i need advice
 

picked up a r90/6, needs some rewiring in the headlight bucket. i cant get the generator light to come on when i turn the key on and i think this needs to happen and im not real sure how or what to do next. any ideas appreciated. are there any good books out there that someone could suggest for the airheads? thanks greg

This is a common car/truck/bus type alternator system, any books on those should help you unerestand how this system works. Local lib?

http://www.ibmwr.org/r-tech/airheads...ing.info.shtml

You could have a blown globe, alternator rotor open, brushes worn out or a broken/dissconnected wire. In that order..

Still want a book ? http://www.motoelekt.com/goodstuff.htm

thanks frank i will check it out.

The book from Motorad Elektrik is the absolute best authority on airhead electrical systems.

And Frank is totally right. It could be one of a bunch of things that make the light stay out. If you wind up having to replace the alternator, you might want to consider upgrading to the 400W alternator they offer now.

What Frank said. What Kbasa said. And definitely what motorrad elektrik says.

I'd probably be lazy and go for the bulb first, but that's totally trying with luck. No substitute for the careful systematic approach.

Definatly try the bulb first, cheap and easy.

However, don't be suprised if it ends up being a failed rotor. The speed of a boxer crank cycles up and down every revolution, and with the direct coupled alternator, that gives the windings a pretty good shaking, thus airhead alternator rotors are a fairly high failure item. The good news is that rebuilds are readilly available, and halfway reasonably priced...economy of scale.

Unless your rich, don't just try things, it's not that hard to pinpoint the cause before shelling out for parts.

Greg,
Here is a great place to go for Airhead Technical Tips......
http://tinyurl.com/2g3tj The whole URL is http://www.airheads.org
This is the basic diagram of your charging system http://www.buchanan1.net/charge.shtml
and it is referenced here http://tinyurl.com/2fls3

This should be more than enough to get you started.

Mick :thumb

Here are a few more:

http://w6rec.com/duane/bmw/bmw.html

http://home.jps.net/~snowbum/techindex.htm

also www.boxerworks.com.

On the Airheads, if the bulb doesn't work, it won't charge.

I had the same problem on the R60/6 I ride, and the problem turned out to wear and tear on the wiring harness where it goes from frame up into the headlight bucket. After beating my head against the problem for awhile (and testing most of the stuff people mentioned here) I finally took it to a shop where they wanted to 1) cut off the head end of the wiring harness and splice a new one in, or 2) replace the entire wiring harness. As it turns out, they were able to fix the problem with an skilled application of electrical tape, but be aware you may embarcing on an expensive repair cycle and you'll want to test the wiring harness through the full movement of the handle bars!

thanks guys i intend to get started this weekend on the electrics project.

i have asked this question before without success, i will try again. when i took the front cover off of the engine there is a big yellow i dont know what to call it resistor or capacitor wired into the ignition, im talking big like about the size of a roll of quarters. anyone know what this might be? thanks greg

I'm guessing the condensor? Pictures would help.

My guess would be condensor. Make sure you disconect your negative battery cable before you take off or put on the front cover, very easy to blow your diode board.

i really dont think its a condenser im thinking its some kind of bypass for the gen light. i will try to get a pic thanks greg

upsman,
The Gen light parallel resistor is either in the instrument cluster or up by the regulator. NOT in the timing cavity.

Mick