Odd bottom-bracket drive-side on 1987 Triumph 3-spd

[DxMachina]

Good afternoon all

After several helpful replies from members here to my enquiries about removing the creaking bottom bracket and knackered cotter-pinned cranks from my 1987 Triumph 3-speed, I have plucked up courage and ordered the parts, and begun disassembly

The bottom bracket drive-side looks pretty odd, unlike expectations. Can anyone advise if this is a false-front over a conventional bearing cup, or some specific part made only for bikes with full chainguards (which this has, normally)

The notched plate actually moves slightly when the chainguard support is turned. Maybe I should just try and unscrew it that way....

Either way I've gone too far to turn back - I removed the cotterpinss with a hammer and pin-punch!

from top:

I am swimming well out of my normal depth here. Very grateful for advice

 

[Some Guy]

Difficult to tell from the picture/post but.. It looks like a suport for the the (partial) chain guard. I removed one from a '70/80s folding bike recently, it simply fitted between the frame and the fixed cup. Unscrew it and see what you find.

I'll add my usual proviso, "I'm sure someone who knows what they're talking about will be along soon"

 

[DxMachina]

Thanks
Just to elaborate, the two arms of the chainguard bracket are one piece, and are clamped semi-tight to the frame by the metal disk in the middle - which has a flat edge on two sides, apparently for a wrench

I wasn't sure if that metal disk IS the fixed cup or just something fitted onto it.....

 

[Some Guy]

Not exactly sure what you mean.. But I think you'll find the chain guard bracket is held to the frame by the fixed cup.

Unscrew it and find out

 

[DxMachina]

1. Went to B&Q to buy a large adjustable wrench to remove fixed B/Bracket cup

2. Got home, unpacked wrench, it immediately fell into 3 pieces due to a missing axle

3. Fixed wrench with large M6 bolt

4. Removed the odd-looking fixed cup, only to find I'm NOT the first person to work on this bike, and it was a caged ball-bearing race and not original to the bike

5. Took wrench back to B&Q for a full refund.

Good morning's work, that.