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Looking at the clutch, it seems that the clutch springs were not done up with the correct tool, or even a chisel with a divot ground in it

The screws are flush with where you could get it with an ordinary screwdriver, or a smaller one used on just one side with a hammer used to drift the screw round. Oh well. Everything else look OK:

On the other side, the timing cover came off easily

and looks fine at first glance. I pulled out the bodged wiring loom, ignition coils and mounting brackets, and removed all the oil lines from the tank. Then removed the screws holding the toolholder in:

Both the oil tank and toolholder are now free, but will not come out until I remove the rear fender I think. Then, 'twas beer o'clock and tools were downed for the day

See if you can get hold of a late primary chain cover, they have the window for timing the bike.
It would be correct for the engine year too.
The old heap has been dropped at some stage so the dinged primary is standard, put a welding tip
on it and it'll be like a banana unless the bloke who's doing it is good. JB weld is fine in there if done
reasonably well.
Love the points wiring lol.

A couple of tips.
Leave the gearchange return spring mounted, do not disturb this unless you suspect the change is not clean in both directions, the spring is mounted on an eccentric which is turned to tune the change action, if its good dont mess with it.

The clutch plate stack is very worn, as shown by the amount of free threads on the adjuster, budget for new steels and frictions for the rebuild, the swarf is most likely from the adjuster screw chewing into the inspection cap, I have had cracked cases successfully welded before , SRM did the fix, best get someone who is V competent for this, or stick with the JB weld repair. Nicks suggestion is a better fix. giving easy access to the strobe marks.

You might want to re assemble the rear wheel and brake after removing the oil tank, its very useful to use the brake when undoing transmission Fasteners.

Or use a dry clutch and not worry about the repair. If using an epoxy like Jb weld, you need all the oil removed from the case, before application. Using a dremel sander will help remove any varnishing before applying, but once it’s on it will give a good seal for a very long time.

Thanks guys. I know what you mean Gavin, but the whole thing is going to get stripped down.

lookin at the pics, you have the later 3 spring clutch, the earlier flat top ball type oil pressure relief valve, a V early primary chaincase with no strobe plate, late 70 or 71 timing chest with the ball ramp clutch actuator and adjustable gear change return spring, late 6CA type points. The case Fasteners dont look too bad , not too many signs of butchery, apart from the points wire.And that looks better than the usual bodge.
Guessing that the core of the motor is 70 and the old primary replaced an early prang victim, probably what claimed the original front end

But apart from the clutch, the oil relief valve, the primary chaincase, the timing chest, the clutch actuator, the gear change return spring and the points, it's all original, right?

Yeah , forsure , still a good bike, most of the wrong stuff is better.

Nothing on this motor indicates '67 to me. That's a '70 on both sides... Except for the early primary cover.

The raised VIN pad and cast-in stator mount proves that.

Hardware holding the primary and timing covers will be different between 67 and 70 so tread carefully when repaving hardware.

This is a good time to check crank end float, remove the 4 sump plate bits , pry the flywheels left /right, if you hear a clunk, try to measure it with a clock gauge on the end of the shaft at the primary , this is good to know, and will help later. It should be close to FA , which is in laymans terms 0.0015 to 0.003 ", or put poritry , just perceptible.

Not really, cast stator mounts were used from 68, and late 68 build motors (NC) had raised number pads. But since it’s fitted with 69 and earlier barrels then I’d say it’s a 69

Still not a '67. Allan, do you know if the '69 cases had the raised pad without the BSA imprints in them? I have a set of cases that match this (small studs, no imprints).



I think you were joking there, but apart from the timing cover it appears to be '69 based on the barrel studs.

Far from it (from being a 67)

There were different variations on the castings around that point.

The first lot were not machined at all, and the numbers stamped straight on the casting.

There were others where the whole area below the casting was also raised, but the area for the numbers was machined and had the BSA backing stamp,

then the more common type which is like the first but a machined face with backing stamp.


All in 69'

More sadly the "TA/LA -Y" numbers were used regardless of 69 or 70. Some even marked up with an X but I don't think Ive seen more than 1 (that would have been a set of cases on a jumble somewhere)

This is a Y numbered engine (can't recall ifY or -Y, will check)

So I got the rocker cover off today





Also took off the points to show the advance/retard


Not much to report, looks clean enough. In other news, the middle engine mounting bolt is MIA:

The rear fender looks to be a Hornet/Wasp style. Hard to source those. It has value.

And it's in great shape too, Gary. It should clean up well

If it's suspected of being anything other than a '67 (which it is)
You can stop all the procrastination by having the bloody thing carbon dated.

OR just tell people it's an old beezer and ride it.

Carbon dating for motorcycles...I'll bet Ichiban Moto has a video on that...

OK chaps, I got the inner timing cover off with no real issues, but one oddity I wasn't expecting. The back of the advance/retard mechanism just doesn't want to be removed:

Once the inner cover was off, the intermediate gear is connected to it:



How do I separate them? Just a puller, or something more subtle?

Also, here's some shots of the gear side now the cover is off:






Some fairly thick, gloopy gearbox oil there.

I’m not sure of the thread size but a bolt will be thread-able into the AAU (didn’t need stripping apart) once you’ve found a long one that fits. Grind about the first 5 threads off so that they go past the threads of the AAU, when tighten this it should push the AAU off the idler gear

The workshop manual explains how to remove the AR mech.

Looks like DD oil pump.

Thanks guys. Adam, what is a DD oil pump?

This is the best pump BSA made with one exception - it still have zinc alloy body.
The last pumps from 1972 had cast iron body, much less susceptible for leaks between two parts of the body and much stiffer.