GS1100 Engine Oil Leak Question

[Tourmaster]

Looking at purchasing a second GS1100. Found another 16 valve, chain drive unit (1983) but the current owner says that it has an oil drip coming from the bottom of the left rear engine side cover. This drip he claims is only evident when the engine is running.

For now, I'm guessing that this is most likely either a problem with the shifter shaft seal or the final drive sprocket/tranny shaft seal. I suppose there may also be the possibility of an engine case gasket leak. When I go to look at the bike, I will have this case cover removed to verify exactly what the issue is.

I'm just trying to get a feel for how much work these possibilities may present. For example, can either , or both, of the shifter seal and final drive shaft seals be replaced without splitting the lower engine cases?

If it is an engine case gasket leak in this area ... I may be able to JB Weld the area to stop leaks of this nature, at least for the time being.

Anyways ... would appreciate some advice on this potential problem area, and just what might I be getting myself into. Thanks

[blowerbike]

worst case scenario would be if the motorcycle had slung a chain sometime in its life and cracked the case under the sprocket cover.
IMO your question covers to many"what if" areas.
if you purchase the bike...
remove the sprocket cover and look around.
in a perfect world,
the owner would let you/him remove the cover and have a look-see.

[Tourmaster]

Thanks ... and yes I realize the question is quite open ended. However, just out of curiousity can either the shifter or final drive transmission shaft seals be changed without splitting the halves? I know on my old 750 Honda's, for example, the shifter seal can be done externally. But the transmission shaft seal can only be changed with the lower engine cases split.

[blowerbike]

yes and no.
the shaft seal can be picked out.
the output shaft seal is a different story as there is a retaining ring that gets in the way.
the manual says to split the case's for the latter of the 2.

[Tourmaster]

Thanks blowerbike.

[Tourmaster]

So ... I've decided to purchase the bike that has an engine leak behind the lower left engine case. Turns out, when I did the VIN check, the bike is a 1981 GS1100EX .... not a 1984 GS that the owner thought??? When we took off the engine case in the drive sprocket/shifter area, it became quite obvious that the oil was leaking from the neutral sender switch area. It would drip oil at a steady pace once the engine was running.

When I get the bike home later this week, I'll take this neutral switch out and take a look .. but am assuming this shouldn't be too serious a problem. Had a look at the on-line fiche and I see there is an O-ring in behind this neutral sensor that is fastened to the engine case with two screws.

Is this a common replacement item on these older, hi mileage, bikes ... and is it probably just the O-ring ... or should I be looking for other potential issues inside that switch cover?

[blowerbike]

http://thegsresources.com/_forum/showthread.php?t=164524

[Tourmaster]

Perfect ... thanks blowerbike !