Janos's CBX550F

My name is Janos and I live in Hungary.
Five mounth ago I bought an '83 CBX 550F so my childhood dream became reality. I saw an advertisement in the newspaper: "I sell my Honda CBX 550F cheap". I've never heard about this type before so I was very upset how it looks. I wasn't disappionted. As I watched on the exhaust pipe system I fell in love with it.
Generally the bike was in a good form except painting (it's dark red, not originall and looks a little bit ugly so I'll repaint it in the winter), chain, sprocket, tyres and fork seals. The chian, sprocket and the tyres were to be replaced urgently. The other parts will be replaced in these days because it's winter here now, too cold for riding.
The engine works well but the max rpm is only around 9500 and the max speed is 165 km/h. I think it's a little bit low. Have you got some idea why? I've measured the compression pressure which was 11.5. I think it's good enough. The engine suonds nice by the way. A little vibration appears at ~5000 rpm but now I got used to it.

So write me if you have some idea or any suggestion to keep my bike in the best form.

Merry Christmas!

Janos