Hello Mr Honda
what is a dirt bike "JUG" does it mean the cylinders?
no no not from dirt bikes - they are made by MVVS
another testrun:
http://www.youtube.com/watch?v=_-A84zjWDDo
two times of 58 ccm; so i have 116 ccm.
It turns a 28 x 12" with 6200 (without gear)
and this 4 Blade 28 x 26 with aprox. 3650.... the MOKI 250 comes up to ~ 3300 with this thing.

Gotcha!!
we compare the moki 250 and my engines (with gear) several times and always The RR258 gives roundabout 300-400 rpm's more, depending on the prop !