Isn’t it for initial checking oil flow ? I don’t have handbook with me right now but it was always told to me that I needed KTB Richardson and the handbook to answer most questions and I have found that good advice
ET: Engine (Twin) What’s the Purpose of Oil Quill Screw #227?
- Thread starter craig
- Start date
I've just ventured out into the garage and found my copy of the Riders Handbook. Chankly Bore is spot on re his reference to the little screw. My copy is also the 10th edition and on page 17 it reads:-
'Checking the Lubrication System. The return flow of oil can be observed at any time through the tank filler cap, but it is wise to check over the system at other points occasionally, even if the return flow seems to be correct.
Big End Feed. Oil is fed to the big-end via a quill screwed into the timing side case near the lower corner. This quill, part No. OP 9/2, can be removed bodily, and the central jet hole and also the six radial feed holes can then be cleaned out. A rapid check that the oil is reaching the jet orifice can be made by removing the 3/16in. screw in the head of the quill, but this is no guarantee that the jet is clear, and it is not advisable to push a wire through the jet without removing the quill, as this would push any foreign matter which may have been present up into the internal oil passages. With the quill removed, oil should issue feely if the engine is rotated.'
'Checking the Lubrication System. The return flow of oil can be observed at any time through the tank filler cap, but it is wise to check over the system at other points occasionally, even if the return flow seems to be correct.
Big End Feed. Oil is fed to the big-end via a quill screwed into the timing side case near the lower corner. This quill, part No. OP 9/2, can be removed bodily, and the central jet hole and also the six radial feed holes can then be cleaned out. A rapid check that the oil is reaching the jet orifice can be made by removing the 3/16in. screw in the head of the quill, but this is no guarantee that the jet is clear, and it is not advisable to push a wire through the jet without removing the quill, as this would push any foreign matter which may have been present up into the internal oil passages. With the quill removed, oil should issue feely if the engine is rotated.'
I also read somewhere (Richardson maybe) words to the affect that one should use extreme caution when tightening because the quill is easily broken.
Any of these and banjo bolts will let go if you overtorque them.........the holes weaken them a lot........early bikes had stainless banjo bolts..........equals many stripped crankcase threads hence the repair scheme in the works books, thats why then, the later bikes had alloy banjo bolts.......Of course this all comes back to what sealing washer you use, and the alignment of the banjo's..........You should never use red hard fibre washers under any of the oil feed/return lines, this is deffinately not good, as they are way too hard.........plated/chromed oil lines are a very common cause of oil leaks at these joints due to the ridge on the sealing surface from the wire tying/plating process.........All banjo's should be treated with care.
You should always inspect quills and banjo bolts for the little cross-drilled holes going oval. At a rally in Australia some years ago I saw a scoundrel selling old stretched brass! banjo bolts for $30 each. Chaps like that should be avoided. "Richardson", page 95, first edition: "The quill can be fractured through over-tightening;" and, page 97 "The alloy banjo bolts are lighter and just as effective------------and there is no need to over-tighten them -----".
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Ok, the quill and oil line banjo bolts must not be over-tightened. How tight is correct?
Paul
Paul
Tighten them until you feel them start to fail, and back off 1/4 turn!
That was a joke for those whose sense of humour does not exceed their mechanical inclinations!
I'm glad you said that first. The I wanted to say up to Russian torque "Goodenof" but less than German torque "Goodentite" as "Oops!" is farily close by.
But how tight is an interesting question. I think and interesting way to find the answer would be to sacrifice a couple of new quills in an aluminum block correctly threaded to determine what happens first at what torque. Do the aluminum threads go first, the brass threads, or does it break at the cross drilling. Then only go half way to that torque, that would give a safety factor of two. The A22 banjo bolt would be a different design of experiment as you have it going into the aluminum of the engine and the steel of the oil tank. You would need an aluminum block and a steel block correctly threaded. Plus different material for the banjos themselves, brass, aluminum, steel. I don't think it would have an affect but to be absolutely certain I think you would have try.
I despise when I get curious like this, it ends up costing me money and things get broken.
If the correct type of banjo washer is used, the limiting factor is the strength of these washers. That is.......if the banjo bolt is tightened too far the sealing washer will split and fail.........As for the quill.........well that does generally use a small fibre washer, a copper asbestos type crush washer, or even a Dowty type seal will work..........As no oil pressre exists, it does not need to be overly tight.........The best way to help advise those who have limited "feel" with these things.........use a spanner of the correct size, and keep your hand as close to the fitting as possible, then use moderate force using one hand only........that way you are limited to exerting inch pounds of force rather than foot pounds, which in the case of the fine thread of the quill would only end in tears.........for the engineering gurus out there who condem the use of fine threads in alloy.........there are fine adjustments, and then there is vibration.........bikes like aircraft suffer greatly from vibration.........there is your answer.