The BSA A7-A10 Forum

Technical (topic titles must be descriptive) => Gearbox, Clutch, Primary => Topic started by: alanp on 18.11. 2010 16:31

Title: Gearbox oil leak solved?
Post by: alanp on 18.11. 2010 16:31
I've been trying to track down an oil puddle under the bike. I've been placing a newspaper underneath and over a period of days a puddle appeared larger and larger at the front end under and to the off side of the engine cases. My first thought was timing case gasket, but no.
The clues - 1st, it was gearbox oil since it was nice and clean but nowhere near the gearbox. 2nd, it was collecting on the bottom run of the speedo cable and falling onto the lower frame tube and moved along, just to confuse me. 3rd, I traced the oil on the cable back to the connection with the gearbox.
So, I checked that the connection was tight with no movement of the cable and then unscrewed the cable end from the gearbox and couldn't see anything wrong, the nylon bush on the inner cable was at the gearbox end and I didn't really fancy taking the gearbox cover off, the garage was cold, so reconnected the cable and placed fresh newspaper underneath again.
The following day the puddle was back!
Thinking back, I remembered the cable connection at the gearbox being tighter to screw the nut onto the gearbox drive than I expected by hand, and had to use the spanner to take it up (no, I didn't cross thread the nut, so there!). 
Back to the cable to figure out why. This time I disconnected both ends of the cable and connected the gearbox end first, almost fully up by hand this time, and then the upper connection at the speedo head.
Result - no more puddle or sign of oil on the cable.
Now this may be just a function of my cable parts but keep it in mind, you never know when the gremlins will invade.
Title: Re: Gearbox oil leak solved?
Post by: dpaddock on 19.11. 2010 01:10
This is a good time to remind all of us re the oil leak potential at the speedo connection.
Thanks, Alan.