T160 Oil In Tacho Cable

[Walthamrob]

Hi there, has anyone experienced oil pressure in the tacho cable then leaking upinto the rev counter? I’ve read somewhere else that this is due to the helical oil way in the rev counter gearbox and a fix is to drill a drain hole into the crankcase!! Or should I have a special tacho cable?
Would be useful to hear your opinions.
Thanks

 

[Rudie]

oil pressure in the tacho cable then leaking upinto the rev counter? I’ve read somewhere else that this is due to the helical oil way in the rev counter gearbox and a fix is to drill a drain hole into the crankcase!!

Is nonsense. T160 (any Triumph or BSA triple) is 120 degrees between pistons/cylinders so does not not normally have crankcase pressure changes and, for what little change the crankcase pressure experiences due to heating, they have a large vent area into the primary chaincase (and then the airbox if standard T160).

If the crankcase pressure is so high it can really force oil first into the tacho drive gearbox and then up the cable into the tacho head, the engine has a serious problem - bores worn really badly? But in that case, standard airbox, it is also smoking like a coal fired battleship and the air filter element is soaked in oil.

Or should I have a special tacho cable?

No.

 

[solomon]

a fix is to drill a drain hole into the crankcase

Yikes!

When lubing cable, top few inches left dry can help prevent the cable as it spins around pushing oil up. That's probably where the oil has come from? Over enthusiastic cable lubing?

 

[Walthamrob]

All sorted, was unaware of a service bulletin issued by Triumph which explains that this was not an unusual issue.
I’ve drilled out the bearing and inserted an o’seal and washer as per the service notes, been for a ride and all seems ok.

 

[sikatri]

Interesting! Good update.