Hi.
I just returned from UK after 6months,I have a newish Yamaha Nouvo 135 it took me about 5 hours of messing about to start bike (left old fuel in) is this normal after long period never had same trouble at home with modern bike or even my old Lambretta . When I need to store again is it best to drain fuel,any tips would be appreciated.

The thing with long time storage is that some say you should fill up your motorcycle with gasoline and others say you should not do that. The problem is that they both right, first you should try to avoid filling up your motorcycle with gasohol, as gasohol contains ethanol and ethanol attracts water moister... which can cause corrosion.

Gasohol, and even gasoline, will over time turn bad – it will expire and will not burn correctly. This incorrect burn can cause damage to valves and the piston.

Therefore the best way to store your motorcycle for a long time is to fill your motorcycle up with petrol/gasoline and add 2 or 3 drops of 2-stroke oil to the petrol and mix it.... The two-stroke oil will mix with the petrol/gasoline and will help to keep the gasoline from expiring to early. It also protects the inside of the gasoline tank from rusting as a positive side-effect.

After you take your motorcycle out of storage your motorcycle will produce a bit more smoke, but don't worry the extra 2 or 3 drops of two-stroke oil also helps to keep things moving smooth after not being used a long time....

@ThaiDesign, when your tipp with 2 or 3 drops of 2-stroke oil means 1% then you get 100 points for this.
And please remember that not only Gasohol contains Ethanol, there it's 10% but also the Benzene contains up to 5% Ethanol.

So the only thing to do when you store a bike or a car for a longer period is to get the gastank empty (that's what Kawasaki recommends for their bikes in storing for winter time).
Only the old leaded fuel was able to store for a really long period (a friend of mine did it for round about eight years and even after that time in my Porsche 930 turbo the difference to unleaded 98 ROZ was very big).

Ethanol is a hygroscopic substance, which tends to absorb water from the air. The more ethanol in the fuel the faster water will be absorbed from the air. With the air humidity in Thailand sometimes reach as high as 80% (while it's on an average day 59%) this process can happen unexpectably quickly.

It's therefore safe to say that the regular fuel, which correctly contains 5% ethanol will turn less quickly bad than gasohol which contains 10% ethanol.

The best thing is to leave some fuel in the gas tank and replace it when you take the motorcycle from storage. Works for several of our friends who store motor vehicles at our garage for safekeeping....