The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: Minto on 11.04. 2021 01:33

Title: Primary chain tensioner
Post by: Minto on 11.04. 2021 01:33
Hi all, I'm having difficulty finding a primary drive chain tensioner screw 67 1268, my engine is missing this part and the tensioner plate was just bolted up very tight. The hole for the screw is stripped out all bar about 4 threads.
I've tried all the usual places to no avail and I've looked on the nut and bolt chart but it has no details. Does anyone know what size and thread  this part is?
I'll need to fill, drill and re-tap it (when my tap n die set arrives)and find a suitable bolt to adapt.
Sorry about the ramble, it's way past my bed time.
Thanks
Jase
Title: Re: Primary chain tensioner
Post by: Russ on 13.04. 2021 12:06
Jase the tensioner stud, 67-1268 is 3/8 whitworth by 2-1/4 inches. The nut, 67-1266 is a 3/8 Whitworth nylock nut. From memory? I purchased these nuts from Andrew at Priory Magnetos.
3/8 Whitworth nuts from my local Bunnings have the correct thread but not the correct head size for Whitworth spanners. I had the bolt so didn't need to source one.
Russ
Title: Re: Primary chain tensioner
Post by: Minto on 14.04. 2021 19:24
Cheers Russ
Unfortunately Priory didn't have one and as far as I can find, nor does anyone else. I've got an appropriately sized bolt I can use though. Thanks.
Jase
Title: Re: Primary chain tensioner
Post by: muskrat on 14.04. 2021 21:09
G'day Minto.
There's one here https://mikesclassiccyclespares.com/product/67-1268/ post shouldn't be too much.
I made my own from a threaded bar.
Cheers
Title: Re: Primary chain tensioner
Post by: Minto on 15.04. 2021 00:44
G'day Minto.
There's one here https://mikesclassiccyclespares.com/product/67-1268/ post shouldn't be too much.
I made my own from a threaded bar.
Cheers

Cheers Muskrat
Going to do the same with a bolt now I know what size it is.
Jase
Title: Re: Primary chain tensioner
Post by: Minto on 26.04. 2021 21:02
Was going to make one and then one came up of eBay. Hoorah!