How long ago are we talking? I would think the only way would be through any club(s) or friends who knew them and the bike. I assume you know the registration mark?

Well Calum at least you’ve found the problem. I must confess that I drilled out the apertures on all those bolts on my B31 as 1/64th seemed to me to be too easy to clog up with a bit of debris. I did open up the lower ones more so. I haven’t found it to flood with oil yet or smoke. If it does smoke more as time passes I’ll renew the rocker box ones, they are easy to get to.
Pete

I don't suppose it's likely to flood the top as long as the drain holes are considerably larger than the combined area of the supply banjo orifices. I'll remove the drain pipe and drill the bottom banjo out to match the top and see how we get on.

Have you had the head rebuilt. Sounds like wear on the valve guides. Oil in the head sucked into the engine down the side of the inlet valve.

Nope, never had the head off. There's no smoke on the overrun or going down long hills to speak of so I don't think the guides are too bad. I do have some jobs planned for the engine in the future but for now I am just enjoying riding it when I can. Once I finally build my new garage I suspect I will spend a lot more time tinkering...

Does the short go away if you back the centre bolt off ever so slightly? It screws into a nut which I believe is encased in plastic/resin to insulate it from the mag body. If this screw is overtightened I believe it can crack the plastic and short across. I only ask about backing it off slightly as a test as I found I had a similar issue on my mag, although with the locktab folded over it did run fine. I couldn't get my head around what was touching where.
I bought one of those timing lights but off someone else on eBay, a little cheaper than the one from 'the magneto guys' but both would be a worthy investment. Very helpful in my diagnosis work on my bike.

Mine on my '53 B31 is just like the drawing from the manual above. It slides into the clips in the bowl, and the glass lens is held in from the inside by a spring wire pushing it up against the rubber seal.

I rebuilt my plunger B31 box recently and I bought a box for spares (many for the good selector forks) but I did end up using a gear or two out of it. It was stamped M20 on the casing but came disassembled so I can't guarantee it was all correct. I'm pretty sure the gear ratios were identical.

Hi all

I have been very much enjoying my first summer of BSA ownership. 1953 B31. The gearbox rebuild proved very successful, and the mag rebuild has all but cured my hot running and starting issues. I've just returned from a 420 mile round trip to Suffolk this weekend and the bike never missed a beat. However one problem which seems to be slowly getting worse is the smoking...

It doesn't smoke from cold. It doesn't smoke when under load, nor when on the overrun. But when the engine is hot and I come to a stop at traffic lights or a roundabout it begins to emit a lot of smoke out of the exhaust! It doesn't always do this however, and I haven't worked out of there is a pattern to when it does and doesn't. As I pull away the smoke very soon clears.

My initial thoughts are the top end flooding with oil, and/or the return side of the pump not being able to pump the oil back quick enough after fast running. Oil consumption is generally quite good, so I don't think the rings or the valve guides are too bad; I also think this would cause a constant haze when moving along, but I am open to any suggestions at all!

1953 Plunger B31 here with the same oil tank also

Hi Callum,

BSAOC Branches are well attended on bikes and some have attendance trophies for branch members.  Some do runs in the evening and weekends and there are the Branch Weekends that include camping and a run out.
There could be other BSA owners and even BSAOC members no too far from you and in the same position.  You could consider sending an invite through this Forum or through The Star to meet up at a local cafe or pub.  You never now you may get a good response.  As you are a younger member you may also attract younger people to BSA ownership - the Club needs them.

Dave.

Yes indeed, I am all too aware of people in clubs having a grumble but not willing to do anything themselves! If I want meets and runs on weekends I can organise some myself with the support of local sections I am sure, so it wasn't too much of a grumble more an observation.

My two local branches are W Yorks and Manchester but both branch meeting points are 30 miles away or more, which is a long way home when the meetings don't start till 8:30pm and I have to take my bike back to the workshop before driving home with work starting at 7:30am the next morning (currently waiting on planning permission to build my modest garage at home, and the living room is already occupied by my girlfriend's Ariel NH!)

To be honest I haven't looked too hard at local branch events recently as I have been quite busy so will take another look and make the effort!

Apologies for the thread hijack