A: Oil Pipework Leaky Banjos

coomo

Active Forum User
Non-VOC Member
Hi Guys.Just shaking down last few issues with my comet/Norvin thingy.On return from run,I noticed a pretty big oil leak.Both feed banjos dumping oil.Pulled them off and replaced dowty washers with factory fibre (189) seals.Still leaking.As you can see this is not a standard set up.Flexi lines, meet the banjos,which have been nickel plated.Im guessing the internal surface of the banjo, maybe too irregular or even too hard (with nickel plating)to seal properly.Maybe next remove banjos and mill internal surface to ensure its 100% flat.Any other suggestions greatly appreciated!
norvin.jpg
 

Bill Thomas

Well Known and Active Forum User
VOC Member
Check the depth of the bit that goes over the rocker feed bolt,
We had some a few years ago that bottomed before the pipe was in contact with the seal,
So the bolt went tight with out nipping the seal
We had to drill it out a bit from inside,
The top flat was much thicker than the old ones,
Just put it on without a seal and look at the gap
NO, I don't think they came from VOC Spares !.
Cheers Bill.
 
Last edited:

vibrac

Well Known and Active Forum User
VOC Member
Using High pressure pipe on a Vincent when the pressure is only a few lbs is a bit of overkill
 

Martyn Goodwin

Well Known and Active Forum User
Non-VOC Member
Hi Guys.Just shaking down last few issues with my comet/Norvin thingy.On return from run,I noticed a pretty big oil leak.Both feed banjos dumping oil.Pulled them off and replaced dowty washers with factory fibre (189) seals.Still leaking.As you can see this is not a standard set up.Flexi lines, meet the banjos,which have been nickel plated.Im guessing the internal surface of the banjo, maybe too irregular or even too hard (with nickel plating)to seal properly.Maybe next remove banjos and mill internal surface to ensure its 100% flat.Any other suggestions greatly appreciated!
View attachment 43022
Many Vincent’s suffer from leaky rocker feed bolts in part caused by the tops of the banjo fittings being distorted through overtightening of the set screw. This problem is aggravated by the small size if the heads of the normal ¼” BSF screw (shown below on the right) used at that point as they do not span the top of the banjo sufficiently and as a consequence put the clamp force on the unsupported centre of the banjo.

A significant improvement can be made that helps prevents the banjo from becoming distorted in the first place by replacing the standard feed bolts with the oversize head ¼” BSF screws that have a head the size normally found on a 5/16” screw (as shown on the left), that are used on the Amal Monobloc carb. When used with a suitable washer this spreads the clamping load over a much greater area thus preventing the distortion of the banjo.

In the UK, Available from D.Middleton & Son (www.stainlessmiddleton.co.uk) described as BSF 1/4 X 1/2 Large Head hex set (for Amal carb).


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brian gains

Well Known and Active Forum User
VOC Member
wasn't going to repeat good advice above. However it is worth saying that the Videan seals i've used have been cycled several times and still seal. Also used the smear of loctite or hylomar on copper washers with good results.
 
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