new injector

Found an injector from a nissan jecs A46-00 . mine is leaking fuel into the electrical connector.
Any reason why this wont work?
cheersSMP 485cc 46lb Full Length Hose Tail Fuel Injector

Fuel injectors are rated for flow at a certain pressure. Just because they have similar body styles doesn't mean they have similar flow ratings. If you're lucky enough to find part numbers on both the Kawasaki injectors and the Nissan injector and can find a crossover reference, you might get lucky, but highly unlikely.
You might get lucky at a fuel injector shop and find a replacement. They can flow test your existing injectors and then find a replacement injector. 

Yes, these are the same body but twice the fuel capacity so may run a bit rich!
fuel capacity is in lbs/hr or cc/min, then there is cc's for the cylinder I think, an ohms reading and recommended feed pressure, aftermarket chinese rubbish and ill informed injector sales people.
good fun