Hi, I have a 1994 Cbr 600f2, It will start and run strong but after about 2 hours of riding it will bog down and die. I can tell when it is coming on because the exhaust note changes and it progressively loses power. When I bought the bike the kid told me it needed a tune up, and it had maybe a gallon or two of gas in it. I rode it on two different occasions for short 1-2 hour rides with no problem. I know the bike needs a cam chain tensioner but don't know if this is related.

 

I'd replace the tensioner, it may be that when the engine warms up to a certain point, it allows the tensioner to slack off, which thows your intake/exhaust timing off causing the loss of power you describe.

while you're at it, change your oil and filter if you havent already done so. for me, when I buy any vehicle, thats THE first thing I do. if you know exactly when its last been done its less to worry about later.

 

I'd check your air filter too...