Assuming its the CB750:
This issue has come up before and my position is thus:
The chain adjusting mechanism, brackets and bolts, is there to adjust the chain and that's all. After the chain is adjusted you crank down on the axle nut to 75ft lbs and that is all that holds the wheel. The adjuster mechanism is not intended to be a fail safe to improper axle nut tension.
Some people have been unintentionally saved by these bolts, but the problem was lack of axle nut torque.
With the axle nut cranked down you can remove those bolts and put them in your pocket. The only reason they have lock nuts is to hold them in place so they will be there the next time you need them.
Now about breaking one. Those are hardened bolts. I know others have broken them but i can't imagine how. Either the axle was not loose enough or they seized in the bracket (rust).
This is all my opinion. I'm looking for documentation to back me up.
Well my Google search turns up many other forums where this discussion takes place. In many cases someone claims that the adjusters were an important part of holding the wheel. But then they don't disclose if they had torqued the axle nut full or not.
Still, no absolute definitive has been found. But i stick with my opinion, willing to discuss it, not likely to change my mind.
There have been threads here where the rider said he only snugged his axle nut because he was afraid of binding his bearings. Yikes! That took some explaining.
