Bought new plugs & it fired up!
I sprayed wd40 round the inlets & had air leaks on 1 & 3 cylinders so I took off all the inlet stubs & reseated them with blue hylomar which cured the problem.
Went out for a quick spin & while better by far, it still wasn't right, so I called into Motrac Racing who are just around the corner from me on it.
He was a really helpful bloke there, telling me that 1 3/4 turns out on the pilot screw as per book makes them run lean & to try 2 - 2 1/2 turns out. He also said to clean the carbs again & to run thin wire through the orifices (carefully) to see that they were properly cleaned & remove any remaining muck out.
I went for 2 1/4 turns out on the pilot screws after cleaning them again with carb clean (which I didn't use first time
) compressed air & wire, then synced them up again.Went for another spin
What a difference!
I was a bit worried that a zxr400 might be a bit of a pain to ride slowly round town, guessing its a bit of a highly tuned beasty being small in the cc department.
But I was wrong, its quite happy round town & goes even better when you boot it
Thanks for the advice RedexRobB & masterofinsanity regarding using new plugs & looking for air leaks.
Cheers,
Colin