Just got back from actually talking to the mechanic working on my bike at my local dealership. What a breath of fresh air, as he actually took me to the lift where my bike was sitting, and explained what had happend. The "chec" engine coming on intermittently during riding, but then not showing any "codes" was due to a design flaw in certain production of the C50, which allowed RF (radio interference, from the coils and other electrical bits) to affect the communication that runs in a wire (which is on the outside of the harness and not wlel insulated) between the Fuel injector and the onboard computer. When these 2 lose communication for anything more than 3 seconds, the chec warning comes on. The tech said his memory had been jogged when he had called the Susuki tech line to get some help on why there where no codes and he showed me a booklet with this info in it from a Susuki mechanics seminar he had attended. The fix is a better, stronger insulated wire that is to replace the wire in question, which is being shipped and paid for under my (thankfully) extended warranty. I think this is the same fix that the other posts had talked about when talking about a fix for the chec problem that their fix had been replacing the wire harness. It is not neccesary to replace the whole harness, but only one section of it.
On another note, I had placed an aftermarket tach on my bike. The tech advised me to remove it altogether, as they have had some performance prolems with bikes that have them installed. The tach hooks up to your coil wires, and has a ground wire that runs from one coil to the other as well. From what they showed and told me, the drain and the RF from these tachs can cause some performace issues with the bike, and they HIGHLY recommend not installing them....
Well, I hope this helps...sure gives me piece of mind when the tech takes me through what he is doing, and explains it to me. They have a well satisifed customer. Well, at least that specific tech does...