Basically , the engine is a Honda CT110 "postie bike " bottom end with an XL 125 cylinder grafted onto it, using an XL100 head. The crankshaft recieved an additional 6.5mm stroke ,the result being a stroke of 56mm , combined with a 57mm bore gives an increased capacity of 160cc , and a compression ratio of 10.01 / 1

Although carring a fair load (me),it struggled to rev much further than 7,200 rpm (in any gear), regardless of gearing changes , so after consultations with Adelaide (SA)Honda 125 race engine Guru ,Nigel Camon , the decision was made to replace the existing XL100 head, with the bigger valved XR200 head