The ELF HTX - both sorts - are very fine and strong oils
The 909 is especially for higher rpm's ... have a look here:
http://www.elf-racing.de/HTX%20909.pdf
http://www.elf-racing.de/HTX%20976.pdf
the 909 is an " half-synthetic" identical with the Shell Racing M .
I prefer the Shell " M " since a few years ( on all my Blata motors ) .
It's very good, with the needed high flammabele Point, like all the race-oil sorts, very good lubrication, piston picture ( becomes color dark brown ) against the picture of pistons, which were driven with ,
example : the TTS 2 Castrol ( this is for official street scooter , beginners China - Bikes stock, and so on...
"or you may put it only on all the paper sealings - to make it wet, before installing "
, by the motor revision ....
- because it's no Race oil, no FIM and FIA released oil !! The flammable point is already at 73 degree !!)
( You may have a piston picture , everytime like new, , but this is not this, what the motor needs )
But the castor based oil , needs rpm and by changing oil sort ( from synthetic ) into this kind of oil , you have to re-adjust the carburation setup
( because its a very thick solution ) !
(I have absolutly no resin formation, I drive it between 1:33 and 1:40 ,
depending on my different motor charcteristcs, ... )
Info:
Shell Advance Racing M 30
Castor based racing oil with synthetic components.
Shell Advance Racing M is a castor oil based racing oil with synthetic components, formulated to offer very good engine protection in severe racing conditions.
* Is recommended for 2-stroke karts, it can also be used for 4-stroke speedway motorcycles and other engines burning alcohol.
* Is suitable for premixing systems with a ratio of 1:16 for karts and 1:25 for motorcycles or as specified by the manufacturer.
* Has DPA Technology (Dynamic Performance Additive) designed to prolong engine life, giving you more response from your bike or kart.
* Offers very good engine protection in the most severe racing conditions.
* Helps prevent scuffing, ring sticking and deposit formation.
* Is approved by FIM/FIA-CIK and meets SAE J 300 30 viscosity grade requirements.
...and the price in contrary to the ELF HTX 909 ( and Castrol 747 ) is cheaper !
But everybody should drive ( and test himself) the oil ( brand and sort ) at its own discretion and appropriate for his own motorsetup .. but only an FIM and FIA released oil .
This is my opinion ( and / by experience ) .