I used Castrol R30 in my stock TZR 125 with no problems .It did gum the rings up but I did about 5000 miles using it before this happened,I only used it coz of the smell .
As well as Castrol TTS they make R2 which can be premixed or used through the oil pump. I use it but only coz of the smell as it close to the smell of R30/40 but it aint cheap.
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