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Thread: Upgrades: 50amp Alternator, High Altitude Loop Switch & Hazard Switch

  1. #1
    Registered User burnszilla's Avatar
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    Upgrades: 50amp Alternator, High Altitude Loop Switch & Hazard Switch

    The neighbors must think I'm crazy... I worked on my K75S in the driveway tonite for 7 hours. I finished at midnight. I had the halogen work lights shining on it, my LED headlamp on, drinkin' Red Hooks and fartin'.

    I installed heated grips when bought my bike last year, and I also ride with a Widder electric vest when it gets chilly. I was finding that when running the grips on high and having the vest on at the same time, they were fighting for the electricity and not running at full power. So, after prowling on ebay for months for a 50 amp alternator, I finally snagged one in September. I installed it tonite to aleviate my power shortage, plus i'm going to purchase the wife an electric vest or jacket tomorrow. I ran into some trouble getting the alternator to fit. It just wouldn't slide in all the way. After a bit, I figured it was the nut that was holding the wheel on. It was hitting the receiving end on the bike. I removed the washer under the bolt, put some lock-tite on the bolt and put the nut back on, alone without the washer. Bingo! It was in there like a fat kid on a Ho-Ho!

    After I got the alternator in I figured while I'm at it I might as well install that hazard warning switch I bought in the summer. The reason I bought it was to be able to adjust the brightness of my Kisantech signalMinder with running lights feature. I removed the tank. I searched around for about 5 minutes for the socket that the instuctions (yes, I broke down and read the instructions!) say it plugs into and finally found it tucked way under the wiring harness on the left side.

    Now this might be an informative piece of information for you K75 and maybe old K100 owners. When I bought the bike I read the Clymer manual and learned of the "High Altitude Loop". This is a circuit that is under your left side cover tied to the frame.

    Excerpt from:
    THE BMW WORLD
    AN INTRODUCTION FOR NEW BMW OWNERS OR POTENTIAL OWNERS
    Copyright 1991 D. Eilers.

    High-altitude Operation

    The K bikes have a small socket in the wiring harness which accepts a plug containing a resistor. The resistor "fools" the computer into thinking less air is flowing past the airflow sensor by purposely "miscalibrating" the sensor. This effectively leans-out the mixture -- exactly what you want for high altitude operation. The plug costs about $6 and should be used if you go much above about 4,000 feet for best performance. The plug does make a difference -- my K bike would not idle in the Colorado Rockies without it, but ran fine with it. Some people who frequently ride the mountains wire the plug through an accessory switch (available from BMW) to make the change to high- altitude mode as easy as the flick of a switch. The newer "Motronic" engine computer introduced on the 1990 K-1 model eliminates this need by using a barometric sensor to automatically adjust for any changes in altitude. Motronic is now also on the 1991 K100RS.


    So, I plugged the resistor into the harness and split the loop of wire coming out of it. I soldered a 16" piece of double wire to a rocker switch from radio shack
    that I attached through a hole I drilled in the black plastic cover on the bottom of my left fairing just next to the throttle body. The switch is hidden from view down there, but you can reach it while riding. During the summer while riding in the Sierras it was a pain in the butt pulling over and installing the loop. Not anymore.

    Next project: Installing the Fuel Plus.
    Stephen Burns - 2007 R1200GS
    BMW MOA Lifetime Member
    www.burnsmoto.com GS911 WIFI BMW Motorcycle Diagnostic Tool

  2. #2
    bmwmick
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    Stephen,
    Did you use the clutch hub from the 50A alternator? They are just a little different than the 32A hub. the 32A had a keyed shaft too IIRC.

    Mick

  3. #3
    Registered User burnszilla's Avatar
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    Yes I noticed that. I put the 32amp hub on the 50amp noticing there was no notch. I put it on very tight and used red loc-tite.

    Problem: I took it out for test ride today and I'm feeling pulsing vibrations at around 6000 rpm and up. Coming from the alternator area. Something is wrong. It pulses every second. I replaced all the rubber bumpers with new ones.
    I have to take it all apart to check to see if it came loose.

    Any ideas would be helpful.
    Stephen Burns - 2007 R1200GS
    BMW MOA Lifetime Member
    www.burnsmoto.com GS911 WIFI BMW Motorcycle Diagnostic Tool

  4. #4
    bmwmick
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    Stephen,
    You need to order the correct driven Hub 12 31 2 305 329. The
    50 Alt does not use the fan wheel either so IF that is on the shaft,
    it is probably causing the misalignment. The Hub for the 50A is about
    twice as deep as the 32A model.

    Mick

  5. #5
    Registered User burnszilla's Avatar
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    Ok. I found the problem and let me know if it is related to the part I need.
    One set of the rubber buffer (monkey nuts) fell out when I put the alternator in, causing an balancing problem. Hence, the vibration.

    Yes! I need that part. That's why the rubber pieces fell out. I called SJBMW and ordered it. I'll have it by Tuesday.
    Stephen Burns - 2007 R1200GS
    BMW MOA Lifetime Member
    www.burnsmoto.com GS911 WIFI BMW Motorcycle Diagnostic Tool

  6. #6
    bmwmick
    Guest
    Cool! Now if you just survive that ride across Hwy 17.
    The 'monkey nuts' are the same for both style of drive clutches.
    It's the driven hub that makes the difference. I think it will be fine
    once you have the correct hub on there.


    Mick
    Last edited by bmwmick; 11-22-2004 at 03:21 PM.

  7. #7
    Registered User burnszilla's Avatar
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    Thanks bmwmick!

    I'm getting really good at taking out the alternator. I can do it in about 10 minutes now.

    Oh and one of Eilenberger's Laws came in handy:
    Law#3 - Troubleshooting: Look where you last worked.
    Stephen Burns - 2007 R1200GS
    BMW MOA Lifetime Member
    www.burnsmoto.com GS911 WIFI BMW Motorcycle Diagnostic Tool

  8. #8
    A bozo on the bus deilenberger's Avatar
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    Quote Originally Posted by Burnszilla
    Thanks bmwmick!

    I'm getting really good at taking out the alternator. I can do it in about 10 minutes now.

    Oh and one of Eilenberger's Laws came in handy:

    Law#3 - Troubleshooting: Look where you last worked.
    Steven - cool! And the high-altitude plug? It's not a "resistor" it's a
    simple jumper. Dunno where they got the idea of a resistor, but
    perhaps they didn't know how to read their Ohmmeter.

    Don Eilenberger http://www.eilenberger.net
    Spring Lk Heights NJ NJ Shore BMW Riders
    '12 R1200R - I love this bike!

  9. #9
    Registered User burnszilla's Avatar
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    Picked up that clutch housing, got her all back together tonite and I took a test ride to the gas station to top up. Smooth as butta!

    The wife and I are riding down to Malibu tomorrow for Thanksgiving. We're going to take the pashnit preferred route - 101, G14, 58, 33, 1.

    She wants to learn how to ride a motorcycle now because there isn't enough room in one integral bag for her clothes. Fine with me! In the new year I'll sign her up for the MSF course.
    Stephen Burns - 2007 R1200GS
    BMW MOA Lifetime Member
    www.burnsmoto.com GS911 WIFI BMW Motorcycle Diagnostic Tool

  10. #10
    bmwmick
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    [QUOTE=Burnszilla]Picked up that clutch housing, got her all back together tonite and I took a test ride to the gas station to top up. Smooth as butta!

    Stephen,
    You do good work Have fun in Malibu I was just over that way last month, had a BALL

    Mick

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