ET: Engine (Twin) What’s the Purpose of Oil Quill Screw #227?
- Thread starter craig
- Start date
I use that port to pump lots of oil in there after the bike has been laid up for the winter. Have no idea if it is a good idea or not.
Yup, a good idea, because the Quill feeds the big-end and then the oil goes to the spindles and cams through the timing cover galleries. The oil return in the tank proves the pump is working and that the rockers and valve gear are getting fed. Oil from the rockers also "cascades " down the pushrod tubes and then gets chucked about over the followers and cams. One note of warning. I would never trust the timing case galleries to be clear on any unknown bike. The grub screw(s), 221 should always be removed and the galleries cleaned, likewise the stop valve, OP37. Incidentally I read recently that in P.E.I's opinion the oil feed to the back of the pistons was necessary when high ambient temperatures and high speed were experienced, but not in the U.K. and similar markets.
I'm with you David, pretty sure it is just there to plug the hole from drilling the oil passage up the center of the quill, but wanted to see what people thought it could be used for!
Semi-related
Has anyone ever seen this happen to the quill? Went to gently snug up and it gave way and broke in three pieces. Perhaps just defective if is there something else I should be concerned about?
I was dumbfounded. New engine with 3 miles, had gearbox issues so it sat for awhile, was priming to fire up again and that happened.
The marks on the middle part are from vice grips when removing the part from the timing cover.
Has anyone ever seen this happen to the quill? Went to gently snug up and it gave way and broke in three pieces. Perhaps just defective if is there something else I should be concerned about?
I was dumbfounded. New engine with 3 miles, had gearbox issues so it sat for awhile, was priming to fire up again and that happened.
The marks on the middle part are from vice grips when removing the part from the timing cover.
Attachments
This can happen for a few reasons. The usual one is some ham- fisted primate overtightening the quill, or not pulling away and refitting the timing cover square on to the face with the quill in situ. Many owners remove the quill before lifting off the cover, and this is probably the best plan. However there are snags to this undertaking as well. The thread is a fine one, 3/8" C.E.I. (26 t.p.i.) which is not the best choice for a short thread in alloy. The next possibility is an incorrectly made part, I've seen one made with a 1/8" B.S.P. thread. The third possibility is a misalignment between the mainshaft bore and the inner end of the quill, unlikely in this case. There is always a bit of rubbing here anyway on old machines. The diameter of the scroll should be .236" and the bore, .250". The next possibility is that the quill threaded portion is too long. It is vital that it not project beyond the inner timing case face as the mainshaft runs very close here. Some Australian? made ones fail in this respect, and for the same reason one should never omit the washer, 225, even if there is a nice "O" ring under the head of the non-standard quill. I reclaimed a butchered Comet timing cover with a "special" quill on which I cut a 1/4" B.S.P. thread. In all other respects dimensionally accurate and possibly a better thread in to alloy. This thread would probably also suit a sleeve repair to the Twin primary chain adjuster. I wasn't inferring, Mr. Whiteshadow 15, that you were simian, just enumerating some of the possibilities! A further note, the original drilled bore of the quill was .093" and was marked on the head of original parts I've seen. Cheers from Victoria.
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