so much knowledge here!

well XDl is comming up and i took my powerless (not bogging) motor out of my 2001 f4i
and put my powerful snappy 2002 f4i motor in the 01 frame.
well when i ride now the bike has power spurts then dangerous boggging issues, (very twitchy)

funny thing is, that powerless 01 motor is running strong in my 02 f4i?????!

so now i need to figure what is up is it
vaccum?
electrical?
fuel?
bad (old) part^

I am going to sync the TB's
then imma check all conections
then imma even try a stock airflter...

any other ideas?

my bike has a stock header with A 9 INCH YOSH CAN
k&n filter
60 rear sprocket 15 front

i need to get this straight i havent rode my bike for close to a month now!!!

but i did go ride the bike once to ffind that my bike is running crappy!
my combos got crappy do to power loss!!!!!

my stalls got better cause i have to stay on the clutch to save my as*

i have a mechaninc helping me through this but he doesent seem to know f4i's
so any mech. lingo i can send to him will be great,

 

sounds to me whatever part is bad...it made the 01 motor suck hard and the 02 motor sputter.
did you swap the brain (ECU)too? check that first...then i would go down the list of maybe electrical stuff, check the plugs see if there's a wet one...maybe a bad coil or injector...you may not be getting spark or fuel...but check the easier stuff first and then go down the line.

it could also be a bad fuel filter.

 

Check the fuel pressure regulator. If the diaphram in the regulator is bad it will dump extra fuel into the center two cylinders through a vacuum line. To check it, pull the vacuum hose off the regulator and make sure there is no fuel coming out of the vacuum port on the reg. If it is really bad you will see fuel coming out of the vacuum port right away or just when the pump is running, or if it's not so bad you will have to put vacuum on the port tomake it leak. Put a handheld vacuum pump (like the Mityvac type) on the regulator port, pull a vacuum on it and make sure it holds and doesn't leak down. If you pull all the plugs and the two center ones are fouled (black) and the outer ones are not,then it's a sure sign that the FPR is bad. My '02 was running kinda like you describe and it was theFPR.