K75s Sight Glass Weeping, Replace How Soon?

[TXKbike75]

Hello All,

Had my 88' K75S for almost four years now.  Previous owner did some work and upgrades to it.  This morning I went out to start it for my commute into Austin, and noticed on my pre-ride inspection, that there appears to be weeping around the sight glass (since there's some small oil buildup near it).  I am sure that is one of the items the previous owner mentioned he replaced.  Would it be time to change already, and how soon does it need attention before it becomes critical? And where's the best place to purchase a new one? I commute on it regularly.

Thank you.

[Scott_]

AFAIK, the only place to get one is at a dealer. Aprox $40.
Under normal operating conditions, the crankcase should be in a vacuum.
If yours is pressurized when running, you have another issue besides the sight glass.

[TXKbike75]

Scott,

Thank you for your response. I'll clean it up & look it over better. I use Mobil 1 synthetic, maybe it's weeping from elsewhere & collecting in odd places.

[subforry]

I have never done this but have heard that after cleaning the engine spray the areas that could be the source of the leak with aerosol foot powder.  The oil should stand out against the white powder.

[TXKbike75]

I'll have to try that. Thanks.

[The Mighty Gryphon]

It's a good idea to liberally spray the area of the suspected leak with something like 409 cleaner before dusting with powder.  Let it dry overnight.  The powder will draw out any oil hiding in cracks that has been there for a while and may give a faulty result.

Spray powder is nice, but you can also use a soft paint brush to dust the powder on to the engine.  Then take it for a ride and look for yellow marks.

I learned this trick from an aviation mechanic and have been using it for 35 years in the hydraulic power business.  Works a treat! 

[hector planter]

  Now am sure I read on what once was the motobins forum in the almost perpetual discussions about which oil to use known then as the" Oil Thread" that if anything is going to make your bike leak its fully synthetic  such as your using.  Oh its a shame it disappeared, they had a fantastic library, I thing Airheads had the same view.

[Scott_]

I can say the both of mine sprung leaks(and burned/consumed more) with full syn, that didn't exist with traditional dino. Btw, the leaks also stopped back up when I switched back. YMMV as not all bikes will behave the same way. I think one large variable is the environment that you are/have been in and the condition of the seals.
I suppose with a fresh rebuild, new everything(seals, gaskets, etc) that full syn would be just fine.

I'm not starting an oil thread..... :yow  just sharing my personal theory of the issue.