Author Topic: Crankshaft grub screw semi blocking oilway  (Read 349 times)

Offline Wayno

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Crankshaft grub screw semi blocking oilway
« on: 13.07. 2018 11:25 »
The oil feed hole from the T/S bush is semi blocked when grub screw installed.
While cleaning out the sludge trap on my A7 short stroke crankshaft I noticed that when the grub screw is fully installed, it blocks off half the oil hole from the T/S bush.
I measured the depth of both grub screws, the one I removed from the drive side is 0.322” and the one removed from the gear side is 0.274”.
The parts book states they should both be the same.
Even though the shorter one of the two was installed on the gear side, it still blocks off half the oil supply hole (see photos).
Has anybody else experienced this?  Is it quite common, so all I need do is grind a chamfer on the threads of the grub screw to allow better oil flow?

Online BSA_54A10

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Re: Crankshaft grub screw semi blocking oilway
« Reply #1 on: 14.07. 2018 10:08 »
While you are correct that the plug partially blocks off the oil gallery, the said same gallery is near 20 times the surface area of the 2 oil holes in the journals.
Lots of posts where people have gouged out a channel in the plug and put a reffrence mark on the ehd so it can be indexed to the oil gallery.
Also lots of warnings about not tryng to bottom out the plug which is why you have to stake it.
Bike Beesa