jetting for a SiP JT left hand exhaust fitted to a standard px200

Hi, I have a standard px200 engine fitted with a 24 /24 standard dellorto carb and a sip LT left and exhaust. Could some please tell me what the jetting requirements and, should I alter te timing in any way?

You dont need to alter the ignition timing.The standard jeting is 116 autolube) and 118 (pre mix.you would want to go up a couple of numbers but nothing too dramatic ,try 122  or120 and see how it goes.