ET: Engine (Twin) What’s the Purpose of Oil Quill Screw #227?

[ClassicBiker]

I see your point. I think the type of washer gives us another variable to consider as some, myself included, use the V3 O-rings contained within the aluminum ring. I also believe you are correct, the fiber washers will fail first and therefore fail to seal long before the banjo bolt breaks. I also agree that the quill doesn't need to be overly tight as pressure there is minimal, there has to be pressure there otherwise the oil would not be moving at all. The banjos using the V3 O-ring and aluminum ring could be done up quite tight I suspect as you would be squeezing the aluminum ring once the O-ring is compressed. But as you say the correct sized spanner and your hand as close as possible to the fitting and just snug it up. Interestingly enough that is where on the V3 the O-ring compresses and the banjo contacts the aluminum ring and I feel comfortable snugging things up to, so bonus.
But I would still be interested in knowing where they fail and which fails first.

 

[chankly bore]

I can't plead guilty to be an "engineering guru", Greg. I just wonder why Whitworth studs are used in places susceptible to vibration, such as inlet stub mountings and yet here at the oil quill, the bottom of the handlebar mounting studs and other places, 26 t.p.i. threads occur. Fine adjustment may be part of the answer, so thanks.

 

[greg brillus]

Some places where fine threads are used, we may never know.......Studs and things similar are not disturbed very often, and not affected by heat or size.........example.........exhaust port threads.........A course thread there will cause the nuts to constantly come loose. Damaged threads here are often by the pipe nuts being loose for too long, or poorly fitting pipes where the threads get easily crossed when the installer struggles to align the new pipes......... Banjo fittings need good flat surfaces that are parallel and mate up square to the face of the crankcase........any of these things being out will put a lot of strain on the pipe and the joint will leak........The sealing washers on the feed/return lines should be a softer material than red fibre washers.........it is nice to have a variety of washers to try, some seem to work better in one place than another.........I have had some feed pipe joints were Neal's seals are the only ones that work.

 

[oexing]

Not so soft seal washers like fibre or alu require nice and smooth flats for a chance to seal oil from leaking. Else you better get an o-ring plus ss ring Dowty style instead of fibre, better chance to get this sealed. Plus maybe play safe and put some mild Loctite on the thread after degreasing a bit.
Brass is not a great choice for that oil quill screw, a bit brittle, more so when half a century old. Nobody does bronze screws today ?? Well, a bit of a pain when drilling bronze but take your time, a good drill and lube -you will succeed.

Vic