Last week before my ride this past weekend I installed a NGK iriduim plug. I did not adjust the gap on the plug before installing it, as I was told it was pre-gapped. On the trip this weekend the bike ran great, however, it was baffling back through the snorkel at full throttle in 1st-4th but not 5th. Remember I have an S, not an ES. So I was manually shifting the gears myself. The spark plug was the only thing I changed, but could he just be throwing so much spark it was making the engine bounce off the rev limiter at full throttle in those gears? It did not sound bad, just like a car letting off at full throttle. I have my idle speed set kinda high, I wonder if slowing it down might help. Any ideas on what it might be?