If Yamaha is setting up their plant at Karachi it means they will be doing business indipendently and no local venture, thats good coz local manufacturer's thinking is too much conservative.
I think Yamaha in Pakistan will be the only independent international brand and it might be possible that they bring their modles from India or Thiland, i hope they can do so, in this way investment will not come to pakistan, but new modles can come to Pakistan.
Pakistani Govt. have a soft corner for India and they are willing to start trade with india thats why they reduces inport duty on Motorcycle CBU's in last budget.