Class 1 guys, the gearing should be anything from 78 to 82 depending on your weight and what sort of rev's you want to pull. My sons Jnr TKM 100cc pulls around 15800 on a 10-80 SNR TKM 115cc similar rev's but using a 10-78 hope this helps. These rev's are genrally a blip not sustained and are achieved towards the top of the hill if you carry max rev's through the bottom section.
Steve Grogan