geoffvsjeff

So I like to have (at least) one complete junk bike around for me to tinker with at all times - something I can work on with absolotely no fear of messing it up. In other words, I know the bike in the following pics is a pile of junk not worth putting time into. I know the frame has significant rust. I don't care. Not the point.

One of the first things I do is strip everything down to see what there is, and what kind of shape it's in. The lastest bike has presented me with some parts I am not familiar with. I do not know the make or model of the bike, but the frame looks like an old 10 or 12 speed frame. The crank arm (and I assume BB) are shimano (I think), with some sort of self extracting bolt with a 6mm allen key. The drive side arm came off fine, but the non-drive side does not have an allen bolt on the crank, but it does have some sort of large bolt-like-thing below the crank arm. In addition, when I got the drive side off, it looked like some early octalink-type BB, but with some larger notched ring in addition for the chainrings to hold onto. Between the octalink style BB and self extracting crankarm, it is interesting to see what ideas took hold.

However, after getting the drive side arm off, I have become stuck. I am not sure what to do with the non-drive side arm, and once that is gone, I have no idea how to get the BB out. Please help. I did work at a shop for a few years, so I am fairly good with standard repairs, but I have never seen this stuff before. Pics are included below, since my descriptions probably suck. They are of the allen-less drive side, the bolt hidden under the crank arm, the octalink-like BB with other ring for the crank arm, and the successfully removed drive side w/ allen both and weird chainrings.

Thanks!

Soil_Sampler

https://www.sheldonbrown.com/shimano.html#selecta

https://www.cyclingforums.com/showpos...47&postcount=2

HillRider

Interesting piece of Shimano history. I wonder if the nds allen crank bolt was lost sometime in the past and replaced with a standard hex head bolt under the auto-extractor cover. The "dished" top of the bolt I can see looks like a standard Shimano crank bolt. Try removing the cover with a pin spanner and see what's under there.

geoffvsjeff

Thanks, that makes sense. I'll try it out tonight. How does the larger set of splines for the chainring not get in the way when I go to remove drive side BB cup? It is removable?

LWB_guy

I made the tool shown in the bottom picture here:
https://sheldonbrown.com/tooltips/bbcups.html
to remove my bottom bracket's fixed bearing cup.