I put this bottom bracket on my 86 cannondale a while ago, i can't remember what kind it is and i cant find the tool i used to install it. can anyone tell me which tool will remove it?

Looks like a Park BBT-22 would do it. It appears you've somehow broken off part of the toothed rim that the tool engages, so proceed with caution. It's generally a good idea to bolt the tool to the spindle, either with a crank bolt or, if necessary, a longer bolt, so it can't slip out of the notches when you lean on it with the wrench. In your case that's probably essential.

20 notch Shimano?

https://www.ebay.com/itm/SHIMANO-TL-U...item2c75baf01b

what i remember of the tool i had, it looked more like the park tool than the shimano one, plus i'm reasonably certain it wasn't a shimano bracket. thanks for your help.

What large spline BB tools do you have in your kit? Odds are its one of them. You could always schlepp the bike down to you LBS or CoOp and ask them for the size or even to pop it out.

I believe some knockoff/clones used the shimano pattern for the splines.

i don't think the lip part is broken, because on the other side of the bracket there's the same "partial" lip.

BUT...it has been there for a few years...

I was going to suggest perhaps backing off the opposite-side cup first, so as to reduce the torque requirement in removing what looks like a damaged cup.

I've used alloy cups that had the driveside flange broken completely off, but would then be sure to loosen the opposite-side cup first, as one normally does anyway. The flangeless cup created an adjustable bottom bracket, no spacers needed.

The tool needed here is almost certainly a Shimano-pattern tool.

A long enough bolt with fine threads will not be the easiest thing to find if you do end up having to secure the tool to the cup to loosen it.

I've found such an 8mm fine-thread bolt from a seatpost clamp, but if this bb spindle is fully hollow, then a 6mm through bolt (or even 1/4" threaded rod) might be used with a nut (or nuts) to hold the tool firmly against/in the splines.
Park also makes a lower-profile spline tool (BBT-32) with a much larger through-hole in lieu of the 3/8" square-drive opening, and perhaps this will allow the standard crank bolt to secure the tool using a suitably-large fender washer (or bearing cone-type wrench with 8mm hole for hanging, as some have).

Likely bolting won't be necessary though, if you can hold the tool firmly and squarely to meet the cup while applying torque, use as long of a wrench as possible, tilting the handle slightly inward so as to eliminate any off-axis tilting force where the tool meets the splines.

The opposite side is most likely metal, unscrew that side first, probably left hand thread and then switch sides to remove the remove the plastic cup.

Good eye there, noticing now that the pictured cup appears to be a left-side cup (the ones with a flange that doesn't quite bottom against the bb shell but simply reinforces the spline).

The cup with broken-off flange that I mentioned before was actually a Shimano UN71 drive-side cup, made of alloy.
Luckily, enough of the spline remained allowing it to be turned.

well, my bad. got the bracket off, it's a shimano un70. The drive side was metal, so it came right off. and there was enough of the plastic side left to get that off as well. now, what to replace it with? can't seem to find un7x anywhere. i measured the spindle at 122.5, and i see "bc 1.37 68" printed on the metal cup. so 68mm?

you know, i'm reading, and everywhere I see 122.5mm lengths they refer to "road triple", but i only have 2 chainrings, so did i get the wrong length? should i go with 115 which is "road double?"

The crankset is shimano 600 with "fc-6207 175" printed on it, on an original cannondale 600 sis index system. Hard to find the original spindle length.