What you must take on board is that this is a 37 year old engine with no know history. I find it hard to comment on a engine unless i have been up close and personal with it. You may be lucky and press the button and it starts. For how long is hard to say.
I stripped a CB500 engine a couple of months ago to find the needle roller bearing on the end of the gear box had destroyed itself. The PO told me that it was a running motor but, yes it may have been a running engine with no gears. On the other hand i have stripped CB550 down and found it only needed new chains.
You can tell a lot about a engine from what is in the sump. I can see how much play is in the primary chain from looking in the engine with the sump pan removed but, no manual in the world has this type of information in it. It is a gamble.
I have no clue what your budget is for your project. But the lads on here always say, what ever there original budget was it went out the window a long time ago. I always over budget so not to get caught out.
Sorry for being honest.
