The BSA Workshop > Singles

Cylinder head (1965 B40)

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Phil C:
I'm concerned about the cylinder head fixings on my "new" bike. Photos attached show:
LH side (nearside)of bike:  at the front is a stud with a nyloc nut at the top, nothing at the bottom except the bottom of the stud just sticking out below the casting (might not show on photo); at the rear is a nyloc nut at the top of a stud, and a nut of some kind on the bottom.
RH side (off-side) of bike: at the front is a stud and a nyloc nut on top; at the rear is what appears to be a bolt.
Any thoughts please?  Should I be concerned?    Phil (novice)

PS will need to put second photo on a new message - can't send both on the same message.

The rocker box is normally held down via 9 x studs with nyloc nuts on top. The studs screw into the cylinder head and sometimes the bottom of the stud can be seen poking through. Sometimes people use bolts instead of the studs but this is not a good idea because it's very easy to wear out the thread in the soft alloy cylinder head.

Phil C:
Thanks AWJDThumper, that's reassured me a bit (although I can only see eight on mine.) Also I don't know why one of the studs has a nut at both top and bottom - I just hope it's not because the thread inside the hole has been stripped or badly worn.   Phil (novice)

There should be 9 studs, two of which mount the head steady bracket with another one behind it which you might not have seen. Unfortunately, the nut underneath the stud is probably due to the thread in the head having been stripped which is not an unusable occurrence. Normally, they are easily repaired with a Helicoil.

Phil C:
As I feared. I haven't fitted a helicoil for many years, and have forgotten the finer details of their use. Would it mean the same size stud as original could then be used again?   Phil.


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