Crankshaft bearings

[mojoblues]

Crankshaft bearings are done on my CB650z and I need a replacement. From my net search it looks they are not to be found, not available anymore. Do I have any other options, would bearings from another model fit?
Bike is almost done, it run awesome for a few days until this happened.

[Volker_P]

I think CB500 are the same. I remember comparing measurements in another forum, however I never really verified with the hardware.

[jcasey007]

In my internet search when I needed some I found a few sets with different oversizes but as I expect you have found no one has a complete set in one size.

It is ok to have the crank journals ground to different oversizes (just a pain in the ass) and you have to be careful you match the right journal (oversize) with the correct bearing shell set.

you will have to find a friendly machine shop to do this for you, again explaining the issue to them shows you are not a nutter

This is what I did in the end for my rebuild

[mojoblues]

I was told that 550 would be OK with all the measurements, but the chain (I suppose distribution chain) and its bearing is different so it is a no go. It looks like Nighthawk would do. The bearings I've found (crankshaft and connecting rod bearings 8+10 pieces) go for almost 300€
I had found and ordered complete crankshaft with rods on flebay for half that money. It should be here in 10 days.

[Volker_P]

Well, the dimensions of the bearing halves depend on both the crankshaft o.D. as well as the case bearing mounts/bores i.D.
Depending on that, there are four size classes, not necessarily the same for all five bearings in one engine.
In addition, wear wil increase the factory gap for an old engine so basically one should measure all bearings with plastigauge.

[mojoblues]

I understand what you are saying, Volker. I was told that by my friend/mechanic who is helping me out with this nightmare bike
In the meantime, my new crankshaft came in, it looks much better than my original one. I was also told that I could try and get my old crankshaft measured to see if it can be saved.
We have discovered that one of the oil passages was partially blocked - that could be the reason for the damage to the bearings...
Also, it looks like my oil strainer comes from another bike (looks like from 550), and it doesn't stay put - there is nothing to hold it up..
So, another forum topic, I guess