give that engine a full blue printing, get a descent pipe made and you will be blown by how hard the little green grasshopper will go. The were a 125 on steroids when they were blue printed, so many punters stuck a an alloy muffler on and said how hard they go??? Yeah right.
KX timing, matched ports and a rejet gave them a great surge thru the bottom to mid range with a 125 top end...
Woo hoo