The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: morris on 24.09. 2014 22:30

Title: Plunger primary chain tensioner
Post by: morris 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
Title: Re: Plunger primary chain tensioner
Post by: duTch 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....?
Title: Re: Plunger primary chain tensioner
Post by: morris 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*
Title: Re: Plunger primary chain tensioner
Post by: trevinoz 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".
Title: Re: Plunger primary chain tensioner
Post by: morris 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.