No, not sure exactly whats different and on what years but they have different carbs and displacement
Allow ROSSRS to answer this one shortly, but briefly Rotax 122 or 123 motors are used, both are equally as chocolatety imp:
chars mr tweak (only sent your v5 off this week, crashed scoot, been fucked ) rotax 123 used in the old shape bikes, 122 in rounder new shapes and 06 models. major difference between the two is the fact that the 123 has a cast iron bore and the 122 uses nicosil plated aluminium. the studs holding said bores are also different so top ends off a 123 will not fit a 122 without elongating the holes, unfortunately the 154cc big bore top end is designed for 123's, so need modding to fit the newer bikes. other difference is 122's have retarded ignition at 5500rpm for emission reasons, can be removed by cutting out a rectangle from the back of the cdi and snapping a small bridge of circuit. heads are the same on both. 123 runs coil ignition. 122 got a wank starter motor, 123 has a massive one that doesn't break. cases all seem identical, porting, gear ratios etc. early af1's used a 124.
and yeh, 123 has a vhsb 34 flat slide carb, 122 has phbh 28 round slide. vhsb and manifold fits straight on the 122 and is the only advantage over the 122.
your mum was on the back mate, front wheel no where near the floor, couldn't steer. nah, car pulled out on me, gey.
