oil leak

[zzeedd]

92 R100GS with 43000 miles. Upon completion of a trip down the Baja the battery/charging light came on. upon stopping it was found that there was a serious oil leak from the front of the engine. My first assumption was that a seal blew and oil got into the charging system, which caused the light to come on. Any ideas on the cause of the problem? The bike still runs ok and the oil level is only down a little. What gives. Any thoughts are appreciated. Zzeedd

[willtraubel]

Have a 92 GSPD with 48k on it. At about 30K the diode board fried (shocking..) and when I had it replaced (I was on a long trip) the shop said my alternator rotor was pretty shot too, even though the bike was running fine up until the diode board went: on the NJ Turnpike of all places...on Sunday... in Newark. So I would bet one of those two things may be causing the light to come on, and maybe exacerbated by the oil.
As for the leak> the only oil seal that far up front on the engine is the one behind the alternator rotor. Cheap part, easy to fix. Getting the rotor off is a little tricky and you'll need a small special "tool" to pull it. I believe the Clymer manual mentions and describes it. Basically a short rod with a tapered end that fits inside the rotor so it will pull itself off as you crank on the wrench.
But while you're at it, you may want to consider a charging system upgrade. I installed the one from Euro Motoelectrics (euromotoelectrics.com). Boosts the wattage output to 400 watts, and the best part is it gets rid of the diode board. You'll also replace the alternator rotor and stator with a bigger better permanent magnet one. So if the stock rotor is bad, for about the same money you can upgrade the whole thing. Great kit, has everything you need to do it yourself, including some good directions and the aforementioned rotor puller thingy. I have about 5 K on it and love it, as does my heated vest and driving lights. If you stay with stock, a voltage meter mounted on the bike will help to give some warning of impending diode board failure.....in Newark...on Sunday. :doh

[PGlaves]

92 R100GS with 43000 miles. Upon completion of a trip down the Baja the battery/charging light came on. upon stopping it was found that there was a serious oil leak from the front of the engine. My first assumption was that a seal blew and oil got into the charging system, which caused the light to come on. Any ideas on the cause of the problem? The bike still runs ok and the oil level is only down a little. What gives. Any thoughts are appreciated. Zzeedd

The alternator rotor runs in the front crankshaft main seal. If that seal fails it is likely to throw oil all over the inside of the stator, and may contaminate the slip rings and brushes.

Once the stator is removed, and the rotor is removed, you can remove and replace the oil seal. Not difficult but a bit futzy.

[zzeedd]

THanks for the suggestions! Now all left to do is start the project. Zzeedd

[zzeedd]

Thanks again for all the info! Upon inspection it was found that the crankshaft bolt which holds the alternator core in place had "walked out", setting free the inner alternator works from it's position in the front seal. The result was poor output and the oil leak. I have yet to put it all back together to see if any damage was done to the alternator. I am replacing the frt. seal to avoid future problems with a leak. Zzeedd