hi !!
another ZX-4 owner ! excellent little bikes, and all the better with some ZXR stuff thrown at them.
you'll be trying to do this then
viewtopic.php?f=87&t=6658
you cant get a ZXR 17" wheel into the stock swingarm, you'll need either an H1 or H2 swingarm (H2 is easier as the bracing on the H1 kinda gets in the way.. and L wheels fit the H2 swingarm, H1 has a smaller diameter spindle) its pretty much all bolt on, just need to get the swingarm pivot sleeved down as the ZXR's use a larger diameter bolt, and reaming the frame isnt an option.. oh and a 2mm spacer to remove end-float.. and a bracket to hold the inboard end of the torque arm, I used some 4mm ally plate and sandwiched it between the rearset and the frame.. works fine. Stock shock is fine, rocker linkage can be swapped for that off an L if you want a more progressive back-end, or a plate welded across the top of the top mount and drilled so you can make use of a zxr shock with the ride height adjustor.. depends how tall you are.. the 17" rim drops the backend, so you have to either raise it back up, or drop the front a bit to get the geometry back, I just dropped the front 5mm.
ZXR400-H1 front-end bolts straight in, (L forks wont work by the way, they are about 2 inches shorter, H forks are near as dammit identical length to the stock ones) the steering stem is the same length and the head bearings are the same part numbers, you WILL need a zxr master cylinder though as the ZX4 one wont like the 4 pots, and you "may" run into issues with throttle/choke cable length.. i cant remember what i used in the end, H,L or G .. oh, and the clipons will twat the clocks on full lock, either restrict the lock in some way or tweak the clocks out of the way.. and the steering lock wont work, the lug on the frame is in the wrong place to catch the bolt on the barrel.
zxr carbs are bigger too, and pay dividends with throttle response, you'll need the matching inlet stubs and trumpets (but keep the ZX-4 needles)
