I currently use ipone 2 stroke oil and have decided to buy some castrol now the ipone has run out. My question is can I now put the castrol mixture in with the ipone mixture that is already in my fuel tank?? Or will I have to drain/run the bike out of fuel?? I'm not sure if synthetic and castor based oils will mix, even though it will be a tiny amount of each for a short time( one tank worth )

For the cost of a bit of fuel, just drain it. Better yet, ride the old tank out and fill up with the new stuff. You wont brake your bike.

Synthetic and castor do not mix

Dont forget to drain the carb bowl as well.

What sort of Castrol? Unless it R (vegetable oil) it will mix but the sooner you use the mixed tank the better.

You can mix near anything, synthetic, mineral and vegetable so long as you don't leave them unused long enough to settle out.

Just because it is Castrol does not mean it is a castor based oil. What is it many use, the TTS I think?

Mixing fuel with two different oils? I wouldn't risk it. It's not worth it.

it wont do any harm mixingf the oils. think about it, many times at trials people use other peoples petrol if they forget their own or whatever. I know one guy who done the manx 2 day without brining any petrol and spent the 2 days scrounging from others, how many different types of oil were in his tank?

Many years ago I used to run vegetable oil - shell sport R40 in my trials bike. I had to borrow some petrol with mineral oil in it. Bike ran fine. I also know of one bloke who put about 3 litres of contect duck oil in his tank. Remarkably the bike ran OK even though it stank a bit. the problems only seem to come when the fuel is left and it separates.

Something people do not generally know is that you should not mix 2T oils or greases from different manufacturers or even different products from the same manufacturer. They may have different base and additive packages that can react rendering them useless as lubricants and even corrosive.

a couple of litres in trials bike tank wont do any harm if used there and then