The 97-99 models were quite similar and in 2000 a new style frame was introduced. In 01 a new motor was released in the new style frame.
The 97 model is considered by some the most reliable of the first generation motors.
96 to 97 saw a lot of changes:
New: valve guides, camshafts, rockerarms, autodecompression system, frewheel, counterbalancers, crankshaft, crankcases, clucth springs, pressure plate, shiftdrum, shift mechanism, new exhaust, new carbs on 501 & 600, bodywork, colors, graphics but most importantly the 97 model received the first oil pump equiped motor along with a new oil filtration system.
Here is a question for you. Is your bike a true 97 or is it a 96? Some 96 models have the vin number stamped as a 97 but are actually a 96. The tell tale signs are:
a 97 has a blue tank and frame whereas a 96 has both in yellow
a 97 has 3 slots in the radiator shrould, a 96 has 2
a 97 has a red anodized oil filter cover and oil drain screw
the color went from a redish yellow to a greenish yellow in 97, similar to a tennis ball
The bke pictured above is a true 1997 model with an optional H-line seat. It sold for $8911.00 USD back in 97. The seat cover was extra.
I just noticed that your bike is a 98. Oh well enjoy the history lesson anyway.