i am presently useing unleaded regular fuel but i have a problem. sometimes after rideing the scooter and then i get to a full stop then sometime it stalls for no reason and i did play around with the timeing screw and i know it's not that . i'm thinking thats it's the fuel. should i be useing the best fuel ?

You could use better fuel but I don't think that is your problem. Chances are the bike needs a tune up, even just a minor tune will help. Change the spark plug, clean, or replace, the air cleaner and check the valve clearances.

Get some fuel injection cleaner and run a few tankfuls of it. (I know it's not fuel injected, but it works on carbs too).

Also, are you getting regular service on this bike? Changing oil is one thing but there are other service items that are due at certain intervals. Valve adjustments, spark plugs, air filter, and - if you've been playing with the carb settings you should have a professional put it back where it's supposed to be.

edit: Forgot to say - use regular gas, anything more would be a complete waste. This is a low compression low performance engine.

I'll second what michael said and add one more www.urbanscootin.com it started as a Met site but there are plenty of rucki owners there too. Try to get in touch with spoonkiller on either site that dudu is a freakin master at tweakin the ruck.