Model 16 alloy chaincase Drain Plug

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
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Paul350
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Model 16 alloy chaincase Drain Plug

Post by Paul350 »

Anyone know the thread size? Mine is exceedingly tight may have been cross threaded in the past. Hoping to clean up thread with a tap.

Thanks in advance.
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jackstringer
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Re: Model 16 alloy chaincase Drain Plug

Post by jackstringer »

I'm going to take a stab with BSW aka whitworth. Have you got the bolt handy, measure the size of the bolt width and count how many threads there are and try and work out how many there is per inch.

There is also that dutch site where you can find someone has already measured lots of the bolts. If I.get a change tomorrow I will check my spare case I have in the shed.
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ajscomboman
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Re: Model 16 alloy chaincase Drain Plug

Post by ajscomboman »

Don't think it's Whitworth, I think it's BSF.
Paul350
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Re: Model 16 alloy chaincase Drain Plug

Post by Paul350 »

Thanks folks.

I have measured the plug and now counted the threads . My best guess is 1/8 BSP parallel. That is very near 3/8" outside diameter and 28TPI. Too fine for BSF.
Fortunately thread repair kits are available. Will try to clean up with a tap first.

Regards to All.
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jackstringer
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Re: Model 16 alloy chaincase Drain Plug

Post by jackstringer »

BSP isnt too common in these iirc. But BSC maybe. I have spent the the past 3 days knee deep in thread data so I'm a but over the place, though if you want to know how much how to measure a thread to 0.0001mm and account for rake, compression, flank angle errors and pitch error.
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clive
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Re: Model 16 alloy chaincase Drain Plug

Post by clive »

Paul350 wrote:Thanks folks.

I have measured the plug and now counted the threads . My best guess is 1/8 BSP parallel. That is very near 3/8" outside diameter and 28TPI. Too fine for BSF.
Fortunately thread repair kits are available. Will try to clean up with a tap first.

Regards to All.
I would have expected it to be BSF as that is what AMC generally used for threads into alloy as 28 TPI would be too fine. I wonder if yours stripped and you have a replacement fix.
clive
if it ain't broke don't fix
Greybeard
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Re: Model 16 alloy chaincase Drain Plug

Post by Greybeard »

I wouldnt be at all surprised if it was a BSP thread because its related to an oil supply. They used BSP for the oil tank drain plug and other oil pipe adaptors into ali. :roll:
Dont ya just love British bikes? :lol:

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ajsph
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Re: Model 16 alloy chaincase Drain Plug

Post by ajsph »

I am sure it is 1/8 BSP
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Mick D
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Re: Model 16 alloy chaincase Drain Plug

Post by Mick D »

Hi

If it's PN 012019 then it's 1/8" BSPP - the same plug is used as the PCC and oil tank drains.

Regards Mick
Paul350
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Re: Model 16 alloy chaincase Drain Plug

Post by Paul350 »

Thanks for the help. Cleaned the thread with 1/8 BSP tap everything back to normal.
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