Sorry not replied sooner but I had to get involved in some essential keep life ticking over everyday work.
If you can work on the CBX then you are half way there, it is very difficult to find anyone who will work on a CBX and of course very expensive. I am not sure how owners that can’t do their own stuff go on really, but that applies to most classic bikes I guess.
In terms of difficulty I think my 550 has been a more challenging rebuild that the CBX was, I guess I was lucky with the CBX because although it was in bits it was actually in ok condition. The 550 on the other hand was on the road but a pile of poo. I think if you can keep a 550 the road then you can keep a CBX on the road. But whatever you do don’t buy a bad CBX.
I have got a write up about the CBX rebuild John Whatt did on Bob Curries CBX that went disastrous wrong. Not once does it ever mention about the bead blasting, but that is what obviously what happened. It got rebuilt again by someone but failed again before the guys at SEP reluctantly took on the job of rebuilding it correctly. I believe John Whatt stood by his word and paid for the repairs. I believe one side of the Honda exhausts I have on my bike came from the stuff he sold to raise the cash.
I have seen photos of the inside of a couple more CBX engines that have been grit blasted, what a mess they are totally stuffed and basically scrap. It seems the grit embeds itself in the aluminium of the crankcases and comes out when the oil and cases get hot. Around 10 to 30 mins seems to be the life of the engine.