Tuesday, December 22, 2009

How to stop oil leak at speedometer cable fitting on engine?

My 1994 Suzuki LS650 Savage had developed an oil leak on the right side of engine.after inspection,I found oil leaking at the fitting for the speedometer cable to the engine.I replaced cable because that was the only way to get the seal inside speedometer cable.After just 2000 miles ,the same place is leaking again.What do I do now?How to stop oil leak at speedometer cable fitting on engine?
Why is oil coming out of the speedo drive in the first place?





No Speedo cable I know of is ';sealed';.





Seal it,,and it becomes a conduit for oil up into the instrument.





Your LS uses an outboard right angle drive attatched to the meter---so there's little chance of flooding the meter with oil like what happens with direct cable drive units.





But there is a Safety risk if the leak drips enough oil out of the Speedo and onto your front tire.





I think I'd check the crankcase ventilation system before I'd try to seal something Potentially Dangerous to seal.





14 Years is quite a while.


If the Crankcase Breather's Oil Separator has become gummed-up or carboned-up,,,,it's possible that it can become totally blocked.





The Pressure has Gotta go somewhere,,,and Speedo Drive is a small but Open path.





It pushes oil up the speedo drive shaft,,and into the cable connection.





I'd also check the airbox..it can be filled with oil.


The Case Breather vents to the airbox.


If the airbox loads up with oil (it also accumulates water sometimes).





What happens Then is it submerges the vent.


So instead of the vent having an open path to atmosphere,,,,it gets filled with a column of fluid.


As Crankcase Pressure pulses in the vent hose,,,a column of fluid just marches back %26amp; forth in the vent tract.





It creates a ';Fluid plug'; and prevents crankcase pressure from ever actually escaping,,or at least not at the required rate.





That pressure seeks path of least resistance,,,and Speedo Drive happens to be one.





Run the bike ';hard';,,,or for any extended time at highway speeds,,,and Speedo Drive WILL leak oil at the cable connection.





It may be Easy to just cram a bunch silicone seal around the connection.


But it's not anything even Close to SMART to do that.


And it has a very distinct possibility of Being Dangerous if a certain sequence of co-incidences come together.





......................


Once you get the breather,,breathing again..


a useful trick is to splice a automotive-type PCV valve in the crankcase vent line between engine and airbox.





They're cheap,,and usually available even at Walmart.


Most are 90* ,with one end made to just plug into a Big grommet.


But there are several which are Straight,,and have slip-on hose connection on both ends----this type is usually easiest to use.





Car PCV valves are NOT ';motorcycle duty rated';,,


So they need to be replaced about every 6~9 months in most cases.


They're Cheap,,,$5~10.


And easy to replace once intially installed.





They'll help insure crankcase pressure stays at a minimum.


Sometimes even a vacuum.


It does a BUNCH to eliminate leaks,,,,and usually makes engine run better.


Oil life is often improved also.


Best part is there's No downside to it.





Good Luck.How to stop oil leak at speedometer cable fitting on engine?
You could pull the cable in question loose, clean it with a solvent(things rarely stick to oil), and use RTV to seal it. Its cheap at least, and seems to do the trick for most gaskets and such. You may repair the gasket surface, or simply goop it in the housing if it doesn't need to turn freely at that point.





RTV is Room Temperature Vulcanizing compound and ordinary black is fine. Takes a day or so to harden and another day to cure, so try to not start it for two days so it can make a good seal.





Anyway, before you replace the cable again, you need to find where and when it is getting damaged.
If you cant stop it by cleaning the threads and fittings you can try teflon tape (thread tape) it should work,





good Luck
Speedometer drives usually have their own seals! If it's bad, there's no way you can seal the oil at the cable termination.


Ask your friendly local Suzuki mechanic about it.
just get some rtv silicone if it keeps developing this problem....





or would you prefer to keep replacing the cable every 2,000 miles? lol...

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