+1 to that Mike...
I started out on the hy-vo road because I wanted a high horsepower motor for racing, ideally in the 80s but secretly I'd liek to break 90bhp. With a lightened valve train, crank, rods and pistons, the expectation is higher revs and more importantly where the chains are concerned, higher revs and lightened components means higher rev differentials more often under race situations - i.e. going from high to low revs and back again more quickly introduces more stresses in the overall system. Would I do this modification on a CB750 I was using on the road? Absolutely not.
The view from Mark McGrew is that the primary modification is essential although he stops at the A crank with a flat roller camchain and slipper tensioner - presumably advances in chain manufacturing mean it's less of an achilles heel compared to the Daytona bikes (Weren't they all camchain fails except for Dick Mann?). Also here in the UK, the two CR750 experts worth listening to(IMHO), Pete Rhodes and Bernie Saunders both advocate the primary chain modification. It's not so much a case of if you don't do it it'll fail in race situations but more if it does fail, and you have all those other expensive components in the engine, it's going to be cheaper in the long run to do a little conversion at the outset and this isn't a difficult thing to do.
The hy-vo camchain I accept I have done simply because Pete Rhodes said it *should* be possible but he didn't know if it had been done. I'm a total sucker for a challenge so I set out to fit the hy-vo camchain too and use the DOHC crank. It creates hellish problems with tensioners and the head clearances and I'm the first to admit that I'm not far enough through the project overall to run the engine and see if it works, BUT, it's different, it's been a challenge, it's been rather exciting (sadly!!) to overcome the obstacles at each turn and it's really good fun to be trying something a bit new.
Everyone has their own view of the world and I can see that some people will look at what I've done and think "what a waste of time and money" and that's OK, that's just their view based on their values and beliefs, I don't see it as negative, just different and life would be very dull if we all thought the same