Honda's reccomendation would be 30/1, but i personally run 40/1 on my 21 track bike and also on my rs250, i also ran an rs125 gp on 50/1 for two years with no problems, and that included winning a championship and countless wins etc;, BUT, dont take my word as gospel, i'm an old fart who should know better.
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Proud Father of , 05 ktm 400exc supermoto 2018 honda crf rx supermoto