No balance shafts in mine, rebuilt by flav about 10000kms ago now, hardly any vibration at all, can only feel the tiniest amount through the pedal, but i think thats partly from the low oil in the gear box atm
Other wise no real vibration at all and no engine note changes through the rpm range either.
hey yeah its an old thread but i swear i have a 6k - ish rev limiter on mine seems like a soft cut when free reving a mate swears i lit up his shin with the back fire.. lol but just a very soft "power" cut while driving i.e. no back fire just hits a wall of revs not climbing and no power after 5k