Hi folks , just got my car sva'd and registered, engine pulls fine to 7000 but after that it starts to misfire like hell and won't rev beyond 8000
It has got a large pipercross filter fitted, 4 into 1 manifold (Stuart Taylor I think) I have tryed it with and without the cat ( no change - problem same ) and it has a straight thro ART silencer . The carb needles had 2 washers fitted to get car to pass sva emmissions, took them off, problem still the same. Also new correctly gapped plugs fitted, and speedohealer fitted. Engine is a zx9r c1
I took a bike riding friend for a drive a he thought it was ignition related, I was guessing a fuel mixture problem.
Any suggestions ??

http://www.locostbuilders.co.uk/viewthread.php?tid=45644&page=2

here you go

its the blocking of the air jets you want to try ignore all the other replies for now

Many thanks zxrlocost , just blocked off those air jets, took it for a blast , and it now revs to 12000, feck ! its fast , bloody brilliant, its the fastest thing I have ever driven.
I was starting to get cheesed off , 12 months of toil , expense , and did have a car that wouldnt get past 80 mph.