Here's the thing, faster doesn't always mean better...
I can't tell if you posted the tooth count of the axle sprocket but, it appears to be in the realm of 40t so, for now, we'll go with that...
By using a 14t engine sprocket with the 40t axle sprocket, you end up with a ratio of 2.85:1
By using a 17t engine sprocket with the 40t axle sprocket, you end up with a ratio of 2.35:1
It may not seem like much but, that can mean the difference between going fast & not going at all...
See, if the low range gear is too steep, the kart won't move at all with the larger engine sprocket; my advice is hang on to the smaller sprocket...
Apart from that, with a higher final gear ratio, because it has to work harder, the engine may not reach it's power band &, therefore, top speed will actually be lower than with a lower ratio...