E: Engine Oil Tank Breather Advice

[Speedtwin]

I have started to investigate a recently purchased Rapide C and was looking for some guidance on the breather which on my oil tank tank seems to have been badly blanked off and leaking oil.
Not abd leak but misty and damp I take it this is from a high level air way in the UFM?
Situated beside the oil feed line at the rear of the UFM.
Does anyone have any advice on how this should be is this a normal modification to blank off this boy?
Or is there a better way to blank it off if so?

Thanks.
Al

 

[timetraveller]

It is perfectly normal to block it off. It can either be blocked off near the tank (above the T29) or below the T29 which is screwed into the oil tank. The upper one will require a male blanking piece while the lower one requires a female one. Most of us used the lower one as the blanking piece can be a piece off a type 29 Amal carb float chamber which has the correct thread. It will not leak if it is clean to start with and a decent sealing compound is used. Scott oilers, or equivalent, are a better replacement for the early chain lubricating system.

 

[Speedtwin]

Would a sump bung work in the fitting to the tank I wonder?
Thank you for your advice every day is a school day I am looking forward to getting oily dismantling under there.

 

[bmetcalf]

Do you have the highly recommended Know Thy Beast available from the VOC Spares Co? It has a section that groups parts by thread forms and sizes to help with seeing what plug sizes are where, etc.

 

[Speedtwin]

I do Bruce thank you I will read and make it so.

 

[Speedtwin]

I take it that blocking this breather off has no detrimental effect on the tank breathing and am I right in thinking original design was to send the oil mist from the high level in the tank towards the chain ala the similar Norton oil tank breather design.
Will investigate oil cap sealed or vented.

 

[bmetcalf]

Completely unscientific, but my oiler has been blocked since at least 1980 and my leaks seemed to decrease when I stopped tightening the cap as far as I could and only tighten it past the first detent, which allows breathing. Greg Brillus had posted here about that ~six years ago that the tank itself needs to breathe.

 

[Speedtwin]

Thanks Sir yes that all makes sense.

 

[teunvandriel]

Check that small hole in the oil cap is open, drill it with a 2 mm drill

 

[Speedtwin]

I noticed the remanufactured T27 oil cap has a breather, 27 pounds from many reputable dealers, my well worn original has no breather.