High comp. piston etc.

Hi all you doggies,
                         
                          my XR650L is getting noisy with 25000 on the clock.

  While I now have to open the engine to find the cause, will it be worthwhile to fit a high compression  or big bore piston and perhaps a different camshaft?

  Anybody gone this route and what is the best pistons and cams to use? Who imports them? Any pitfalls?

  My bike is standard but I fitted the following; Unifilter
                                                                          FCR41 pumper carb
                                                                          FMF Q4 silencer

    Bike is used for ADV riding.

    Please fire away.