why is my engine BOGGING?

(NEVADA)

I just placed a 2004 engine into my 2000 BMW K1200 LT. It started the very first time and still does. But, when you turn the throttle up it boggs before the revs can catch up. It is fine at higher RPM’s, but when you go to take off from a stop it boggs for air, and the idle starts to get real erratic. I have gone through every vacuum hose, wires, injector wires, plugs and in-take hoses – everything even throttle-spray cleaner. You name it, I have checked it at least three to four times. Going nuts in Nevada!