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Author Topic: Crankcase Oil Retaining Grub Screw  (Read 997 times)

Offline Terryb

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Crankcase Oil Retaining Grub Screw
« on: 20.11. 2019 19:28 »
I understand that the grub screw, which holds the Oil retaining spring & ball in the timing side crankcase is 5/16".

Is it 5/16" whit?

Mine was almost impossible to get out and I need to re-dress the thread. The fragments that came out look like whit form.

Thanks
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Offline Greybeard

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Re: Crankcase Oil Retaining Grub Screw
« Reply #1 on: 20.11. 2019 19:48 »
I think It's safe to tell you that any threads in BSA aluminium cases were originally Whitworth.
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Online Colsbeeza

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Re: Crankcase Oil Retaining Grub Screw
« Reply #2 on: 20.11. 2019 20:27 »
Hi Terry,
  I am 100% sure it is 3/8" BSW. Having just replaced mine. The 3/8" BSW taper tap cleaned it up perfectly. Another member advised me to use a taper tap, and you want the plug to tighten with a drop of Loctite 569. The plug should end up to be flush with the crankcase surface. If I were you, I would wait until a few others also confirm this.
Colin
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Offline RichardL

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Re: Crankcase Oil Retaining Grub Screw
« Reply #3 on: 21.11. 2019 02:21 »
Just recently watched a video where the machinist working on A7 cases made a cupped version of the screw that provided for more threads at work.

Richard L.
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Offline orabanda

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Re: Crankcase Oil Retaining Grub Screw
« Reply #4 on: 21.11. 2019 04:09 »
Hi Richard,
I have done a similar mod.
Richard (Western Oz)

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Offline muskrat

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Re: Crankcase Oil Retaining Grub Screw
« Reply #5 on: 21.11. 2019 19:04 »
G'day Terry.
While your in there why don't you do the A65 type mod where the ball seats against the pump?

Richard, are those parts for the A65 type mod?
Cheers
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Offline orabanda

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Re: Crankcase Oil Retaining Grub Screw
« Reply #6 on: 22.11. 2019 00:14 »
Hi Musky,
I use the A65 spring in place of the much weaker A10 spring, but in the original location.
Richard
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Offline Terryb

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Re: Crankcase Oil Retaining Grub Screw
« Reply #7 on: 22.11. 2019 09:24 »
Like the modified grub screw with the cup, what spring are you using?
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Offline Terryb

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Re: Crankcase Oil Retaining Grub Screw
« Reply #8 on: 22.11. 2019 09:26 »
Hi Muskrat,

I've heard of this mod. Do you used the back of the pump as the sealing face?
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Offline BSA_54A10

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Re: Crankcase Oil Retaining Grub Screw
« Reply #9 on: 22.11. 2019 19:18 »
Quote from: Terryb on 20.11. 2019 19:28
I understand that the grub screw, which holds the Oil retaining spring & ball in the timing side crankcase is 5/16".

Is it 5/16" whit?

Mine was almost impossible to get out and I need to re-dress the thread. The fragments that came out look like whit form.

Thanks

In the Service Literature, Scans, Links, Documents section of this forum is a post called Nut & Bolt part # chart
Download it , print it out and keep a copy in the workshop.
Look up the part number and then check what the thread is.
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Re: Crankcase Oil Retaining Grub Screw
« Reply #10 on: 22.11. 2019 21:12 »
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Offline Terryb

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Re: Crankcase Oil Retaining Grub Screw
« Reply #11 on: 01.12. 2019 15:21 »
Hi Guy's thanks for all your input. I think I understand the problems now and I will let you all know how I get on.

Cheers Terryb
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