Thinking of buying one for my wifes rvf400.Just wondering were it is fitted,carbs or throttle.She is riding a 250 ninja at the moment which is bang on 33hp.Will the 400 be slower restricted than the 250.I dont know weather shes better of waiting another 12 months and then just jumping on the 400.If you guys can help me decide that would be great.

The restriction is in the carbs, it restricts the amount of air that can enter the manifold rubbers.

I reckon it will be quicker than the ninja 250, the 400 has more torque even restricted to 33hp.

Looks like the Ninja is 20kg lighter but has less than half the torque, so the NC30 is easily the way to go! As if you needed another reason...

A restricted NC30 will (apparently) get up to about 110 mph. On private roads, of course.

Thanks for the info guys thats really helped.She gets about 110 out of the ninja and shes bouncing of the rev limiter in every gear so I think its best to restrict the 400 now before the 250 blows up.