Bicycle Mechanics - Bottom bracket play..

I have some play in my bottom bracket (Shimano 105 9speed). If i grasp both cranks I can rock them sideways a bit, this makes a knocking sound. I cannot move the crancks separately so I assume the play is not in the cranks. I started hearing a weird noise coming from my right crank about 200km ago. I thought it was my pedal but I now think this was probably caused by the bb.
What could be the problem here? The Shimano service instructions do not mention a way to adjust the bb.

Most likely, one of your your BB cups is loose. You might want to invest in a crank puller and a BB tool and tighten it back yourself or just have your LBS take care of it.

I have some play in my bottom bracket (Shimano 105 9speed). If i grasp both cranks I can rock them sideways a bit, this makes a knocking sound. I cannot move the crancks separately so I assume the play is not in the cranks. I started hearing a weird noise coming from my right crank about 200km ago. I thought it was my pedal but I now think this was probably caused by the bb.
What could be the problem here? The Shimano service instructions do not mention a way to adjust the bb.

It sounds to me like you have either a bod bottom bracket or else a cracked frame. Try this: Rock your cranks from side to side as you did before. While you are doing this, watch the bottom bracket closely. Does the bottom bracket spindle seem to be moving independantly from the frame? If so, that's good. It means that you need to replace your bottom bracket. That's maybe a $50.00 to $60.00 job including shop labor. There is no adjustment or repair for a Shimano cartridge bottom bracket like you have.

Erik: It sounds to me like your bottom bracket is just worn out. On the modern bottom bracket they are sealed and there is no adustment. You just buy a new one. I have been curious as to how long these sealed bottom brackets last. How old is your bottom bracket Erick and approximately how many km do you think you got out of it?

I would say it is just loose and needs to be tightened. It is fairly common for them to come loose if you ride alot and especially if you stand and really put the pressure on them.

Or it could be the crank arms themselves are loose and need to be tightened. If you don't feel comfortable in the decision, take it to your LBS and have them check it out.

Thanks! I will take the bike to the LBS to let them check it.

I have been curious as to how long these sealed bottom brackets last. How old is your bottom bracket Erick and approximately how many km do you think you got out of it?
I'm not sure how many km this bb has seen, since this was a used bike. I'm pretty sure the bike was built up in 2001. Judging by the state of chain and chainrings when I got it (pretty much worn out) and the 1500km I did on it, I'd say it's had a fair bit of (ab)use.

Get the sealed insert. My BB was ovaled out, and the sealed insert works great.