"don't panic! If you havn't moved any needle valve screws yet, don't. If you have, try getting them back to factory settings, or if lost, follow theses steps;

SF 501 - Novarossi C12 - turn main needle fully in (gently, as the needle can break if shut down too hard) then unscrew 4 1/2 turns out.

Mid range screw head should be flush with carb body.

Bottom end screw should initially also be flush with carb body.

Adjust idle screw so that there is a 1mm to 1.2mm gap when looking down the barrell.

Change the Novarossi glowplug for a O.S. A3 or O.S. number 8 if A3 not available. (These are available in all good model shops)

Prime the motor. This means you have to get fuel to the carburettor, either by removing the exhaust pressure pipe and blowing down it to pressurize the tank, or putting your finger over the exhaust outlet and pulling the pullstart to pressurize the tank. When you see fuel enter the carb (I take it you have transparent fuel line)

blow for 1 or 2 seconds more to let some fuel enter the crankcase. Turn the motor over with the pullstart a few times, the motor is now primed. Apply a fully charged glow igniter and do the pullstart ritual of creating blisters on your fingers. If it won't fire after 10 pulls, and doesn't lock up, it may need a bit more fuel in crankcase. Easiest way at this stage is to take off the air filter and put 3 drops of fuel down the barrell. Try again and repeat as necessary. If you get too much fuel in the crankcase, the piston will hydraulic lock in the cylinder, necessitating removal of glowplug to empty the cylinder of fuel. Turn the motor over with pullstart a few times while keeping a rag over hole. Replace plug and try again. If it still feels locked, loosen the plug 1.5 turns and try again. Don't forget to re-tighten!

All this time the bike should be vertical, that is front wheel directly over rear. This is mainly to stop unburnt fuel that has been ejected into the exhaust from running back into the cylinder and locking up again.

If the engine is now running, only adjust the main needle in if it is obviously too rich, and adjust the idle to keep it running. A fast idle is best while running in. As the engine gets run in, it will seem freer, lean the main screw only by 1/4 turn at a time then run on the track for a while before adjusting again. Adjust the bottom end screw as necessary, in 1/4 turn increments - If the motor idles ok but splutters, coughs and dies when opening the throttle, with small fuel droplets out of the exhaust, it needs leaning. Turn in 1/4 turn. If it sounds tinny, tends to idle too fast considering the barrell gap, with no smoke or oil out the xhaust, it needs richenng. After 5-6 tankfulls of running on the track, it can almost be said to be “run in."

SF 506 - Picco .12 - Initial settings : Start 5 turns out on the high speed needle and set low speed screw head about 1-2 turns proud of it's casing. Fit OS A3 plug.