www.zxrworld.co.uk

Just took my recently refreshed ZXR to the dyno today. Engine skimmed, ported, kent cams etc. Bike was running fine previously (after engine work) and since then I have fitted Ram Air, Kit ignition Rotor and new exhaust system. However on the dyno today it hit 9000rpm and then ran so lean it was of the gauge!! Tried raising needles, but no change so I then increased jets from 100 on cylinder 1 & 4 and 98 on 3 & 2 to 108 on outside cylinders and 106 on inside which again made little difference.

Any ideas? I don't think changing to the kit rotor should have made much difference, however it is almost as if it is burning the fuel before the piston reaches its optimum point and the kit rotor advances ignition by 6 degrees apparently.

stagger the mains bigger on 2 and 3, not smaller.
108 all the way should'nt be too far off. is this with the carbs with open air correctors?
if so...id say there is your problem. are you paying someone to set this up on a dyno?

having said that if you have altered the ignition in someway...i havent got a clue!

Hi Jake. I am running it on the Dyno myself with some help. Looking at the Dyno guide, the ZXR400G should run larger jets onthe outside cylinders which goes against everything I have always done and this is how the carbs were already set up. The L model is listed as all jet sizes the same. I have not yet blocked of the high speed correctors, however when you do this you normally have to go up a fair bit on the main jet size.