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Help with grub screw location


Website User
VOC Member
With expert help, I have almost completed a rebuild on my Black Shadow engine. But, I find that I have one grub screw too many! The 2 that close the oil galleries in the primary cover are in place and there is one other that measures .233 dia x .53 long that is left over. Does anyone know somewhere in the engine that needs a grub screw that I could have overlooked? I don’t see any indication of it in the parts diagrams and my memory doesn’t help me from the time the engine was dismantled. Is there somewhere else on the cycle parts that it could have come from? Thanks -here's hoping I don't have to take it all apart again! Sam.


Well Known and Active Website User
VOC Member
Grub screw

Hello Sam, The blanking screws in the timing cover are 5/16 according to Eddie Stevens.
I cannot think of a 1/4 grub screw on the Vincent, but even after 40 years you never stop learning with Vincents. Is it whitworth or BSF?
Regards John.


Website User
VOC Member
grub screw

Hello John, thanks for the fast reply! This screw is BSF and I'm trying hard to remember if I took it from the interior of the engine when dismantling it; but no recall as yet. Sam.


Well Known and Active Website User
Non-VOC Member
Grub screw hunt

A couple of days ago I was checking for an oil leak that appeared to come from under my motor around a grub screw! It was not the source of the leak but the oil pump plug OP33 directly above was the culprit.As the grub screw was not leaking I left well alone. Perhaps you are missing this one, it can be seen from below.
It may not be the one, but at least it is worth a look.

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