Author Topic: Plunger primary chain tensioner  (Read 574 times)

Offline morris

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Plunger primary chain tensioner
« on: 24.09. 2014 22:30 »
Anyone know the thread form of the tensioner bolt that goes through the case?
On mine someone forced an M10 bolt through it. I guess I'll have to re-thread it to a bigger size, so I was wondering if it's BSC or BSW originally?
Thanks
'58 BSA A 10 SA
'52 BSA A 10 Plunger
'55 MORRIS ISIS
The world looks better from a motorbike
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Offline duTch

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Re: Plunger primary chain tensioner
« Reply #1 on: 24.09. 2014 22:54 »

 Reckon it should be Whitworth...nice and chunky- that's what mine is, but I think I had to do similar....?
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline morris

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Re: Plunger primary chain tensioner
« Reply #2 on: 25.09. 2014 21:50 »
Thanks for the information Dutch. It looked logical to me that it would be Witworth, but was hoping for BSC as I don't have a WW tap that size. Looks like I'll have to buy one then. First think about a way to explain the wife I need another tool again... *eek*
'58 BSA A 10 SA
'52 BSA A 10 Plunger
'55 MORRIS ISIS
The world looks better from a motorbike
Belgium

Online trevinoz

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Re: Plunger primary chain tensioner
« Reply #3 on: 25.09. 2014 21:56 »
You might have a bit of trouble restoring the thread after a M10 bolt has been fitted, Morris.
M10 is slightly larger than 3/8".

Offline morris

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Re: Plunger primary chain tensioner
« Reply #4 on: 25.09. 2014 22:26 »
You might have a bit of trouble restoring the thread after a M10 bolt has been fitted, Morris.
M10 is slightly larger than 3/8".
Yeah I know, but the casing has plenty of meat, so I will try going to 7/16.
'58 BSA A 10 SA
'52 BSA A 10 Plunger
'55 MORRIS ISIS
The world looks better from a motorbike
Belgium