that's not over heating....vtwin generates alot more heat than your regular Inlines....my RC highest was about 230~240
but I bought a fan override switch from ebay....very easy to install and I just turn it on whenever it hits 190 on a hot day....then it keeps the fan on n' the temp around 190~200 and it doesn't go over
198 degrees is not overheating but if the coolant is leaking you gotta fix that. there is no way that a bike will go from 80 ( or so) degrees to 198 in mere moments, though...and what do you mean max? operating range is 160-200 degrees when warmed up, so max is NOT 198...need more info ;o)