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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Gubro30 on July 12, 2012, 09:40:18 AM

Title: Silverish Gearbox-Oil? Is it normal?
Post by: Gubro30 on July 12, 2012, 09:40:18 AM

Just changed the oil (first time for me) on both the final drive and the gearbox on my 50,000mi K75C.

Final drive looked new, gearbox was dark/silverish looking. Is it the normal colour for used GB oil because of the aluminium components inside the tranny? There was very little, very fine stuff on the magnet, no chunks just dust.

Also, when downshifting, it will sometimes grind until somehow after matching RPM. Clutch spline lubd time I guess?

Thanks!

Title: Re: Silverish Gearbox-Oil? Is it normal?
Post by: frankenduck on July 12, 2012, 09:43:52 AM

Quote from: Gubro30 on July 12, 2012, 09:40:18 AM

Also, when downshifting, it will sometimes grind until somehow after matching RPM. Clutch spline lubd time I guess?

Thanks!

Yes, and sooner rather than later if you're having sticky downshifts.

Title: Silverish Gearbox-Oil? Is it normal?
Post by: Gubro30 on July 12, 2012, 10:50:02 AM

Thanks!

And regarding the oil, any thoughts?

How fragile are those gearbox?

Title: Re: Silverish Gearbox-Oil? Is it normal?
Post by: frankenduck on July 12, 2012, 11:04:36 AM

Never taken one apart but to the best of my knowledge there isn't any aluminum in the transmission.

If ridden and maintained properly the transmissions are pretty sturdy.

If your transmission oil is murky then it's probably got some water in it.

As to the color being different than the FD it could be because the PO used different gear oils in the trans and FD.

Title: Re: Silverish Gearbox-Oil? Is it normal?
Post by: Rick G on July 12, 2012, 08:13:53 PM

I would do the spline lube and change the gearbox oil then change it again in 1000 mile and see what it looks like.

Title: Silverish Gearbox-Oil Is not normal
Post by: kennybobby on July 12, 2012, 09:25:14 PM

i once had a gearbox with silverish oil (lots of shiny flakes).  When i looked inside, one of the ball bearings on the end of the output shaft had enough axial play to allow the shaft to slide and the endmost gear (5th) was touching the aluminum housing and machining fine shards of aluminum.   So it kinda depends on how silver you oil is whether it's normal.  And a gearbox that is grind it until you find it doesn't sound healthy.

Title: Re: Silverish Gearbox-Oil? Is it normal?
Post by: Motorandy123 on July 13, 2012, 08:04:49 AM

Maybe someone added moly to it?

Title: Re: Silverish Gearbox-Oil? Is it normal?
Post by: Gubro30 on July 16, 2012, 11:14:46 AM

I think that might be it - moly added to it.

I still have the old oil in a quart (I have yet to dispose of it) and looked at it again - it's definitely graphite-ish, like there was an additive of some kind added to it.

As for the grinding, it definitely is sporadic, not constant. I'm doing the spline lube this wednesday, will keep you posted guys!

Thanks!