14 Sprocket on a Puchengine doesn't fit without adaptation. On older engines before the V3 engine it virtually never fits.On the V3 engine adaptation of the transmission shaft is recommended. Normally grinding away a few mm with a Dremel or similar is sufficient. That's usually not the end of it, it tends to be tight for the chain to go around, so a little grinding on the covers is usually necessary. But not always. However, it is not an impossible operation, providing a cool top speed with a correctly tuned engine.