I tried that a747 recently and after several tanks full I don't think I'll be using it again. after removing the combustion chamber top it had quite a bit of un burnt gunk inside.

Throughout the time of using it the plug was always black and gunged up.

I noticed that while the engine is running it doesn't smoke much infact hardly at all which of course means its not burning the oil.

Going back to she'll advance kart oil, much cleaner!

From my own experience it does seem fairly critical that the set up is right and the mix is right to ensure (reasonably) clean running.

Obviously modern fully synths will always be cleaner as this is what they are designed to do. No smell though!

Is the shell advance a castor based oil?

I've just read up on this oil and looking at price alone I may be a convert! Fully synth with benefits (smell and protection) at half the cost of A747! WOWEEE!

http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=3&ved=0CGwQFjAC&url=http%3A%2F%2Fwww.opieoils.co.uk%2Fp-69340-shell-advance-racing-m-2t-sae-30-kart-oil.aspx&ei=Vfl_T9DBD_G10QXhmMDmBg&usg=AFQjCNE_GHm8CU3c3x__3Qo3Hp388e7Peg&sig2=OKOQAg_VIiOrJl2VIHZR0w

It even states it is not suitable for dat to day road usage, thus not suitable for a trials bike. You may smell good but your plugged bung may get you in the end!

Got to worth a road test though?

Where I often ride lets me wind it on a bit and get my bike hot on the way home. This must be the reason I don't seem to have as many problems using castor oils?

I always have some build up but not enough to stop me using the oils (A747). I think carb settings and where you ride plays a big part in how your bike runs on it.

I do fully accept though that an oil that is specifically designed for trials will always be the cleanest to use?

"Developed especially for very high revving 2 stroke engines." - Exactly what a trials engine is not.

Spoilsport.

Why dont you run an ordinary 2 stroke oil for engine protection and add a tablespoon of castor oil to every gallon for smell. It won't do any harm and you will get the best of both worlds.

Cheers

I just run the A747? I don't seem to get the same problems as everyone else. I do put a tank or two of Putoline strawberry stuff in if I am going out with the boys sometime but thats only if I doubt fuel range etc so we can share fuel.

I also get it hot at least once a ride. I think these two processes together must help burn off deposits before they form?

I fully underatnd that the synth oils are specifically designed for trials use but I do like the smell of A747. I might have to try adding a dollop of castor in to a jam jar with a putoline mix and see if it gells up. If not I might try it.

I just run the A747? I don't seem to get the same problems as everyone else. I do put a tank or two of Putoline strawberry stuff in if I am going out with the boys sometime but thats only if I doubt fuel range etc so we can share fuel.

I also get it hot at least once a ride. I think these two processes together must help burn off deposits before they form?

I fully underatnd that the synth oils are specifically designed for trials use but I do like the smell of A747. I might have to try adding a dollop of castor in to a jam jar with a putoline mix and see if it gells up. If not I might try it.

Just smear a little castor on your nose. Then you can smell it all you want while still using proper synthetic, in your bike.

Thats why a fresh batch for every ride is the way ahead. I use the rest in the lawn mower or car. I mix a litre at a time so most of the time i'm not mixing up too much to start with. The only time I ever mix 5lts is if out all day etc.