The Honda CBR900RR is a popular motorcycle, at least in the rest of the world, so you should call some big bike shops and used bike part shops. The CDI unit of a Honda CBR900RR is not a fragile item, so a good used one should last for ages unless something else is causing a problem.
Other options are ebay or buy an new one for about US$ 399 from Bike Bandit (Honda CBR900RR CDI unit)
I would advice to buy a new one, as you will be 100 percent sure it's is working....
Hello News
Thanks for the information, I think I go for a new CDI unit
Bryan
Does anybody know where I can get a pattern CDI unit for my 1997 Honda CBR900RR FireBlade? It's running very poorly and I've swopped every electrical component with those from a friend's motorcycle – and the CDI does indeed seem to be the problem.