Definitely. I went on several rides after putting the 28's on it and it was OK by myself but when you had other people with you, ie: extra weight, climbing hills and driving on upward grades the X4 was way bogged down. Hitting top speed was very difficult as well. Doing the weights brought its performance back to the factory level with the big tires. Thats why even Yamaha sells their own big tire kit thats is lighter clutch weights. Theirs is 14g weights which is too light though. 18g is perfect for 28's with stock motor and exhaust.
Hi I came across your X4. I have a X2, and just ordered a X4 with hard cab and heater.
My question is, is it neccasarry to do the clutch work with your tire/rim setup?