www.zxrworld.co.uk

hard to know where to start but here goes i bought an x reg damaged l9 with 14000 on the clock since then have rebuilt the bike while i was rebuilding it found it had restrictors fitted so removed them and also the airbox wasnt all there replaced what i could now its back on the road and below 4000 rpm if you open the throttle it missfires once it gets past 4000 its fine while the throttles open then say if you whant to stay at 70 with throttle in fixed position it missfires again so im now lost ive had the carbs apart 3 times and there spottles changed the airfilter, plugs, coils and leads and checked for air leaks is there any one whos had a similer problem any help would be great

try new plugs, check ht leads and caps, drain the tank and refill with fresh fuel, you set the mixture right?

check the inlet rubbers are tight and are not split i had some thing like that this week after rebuilding my zxr balanced the carbs up put new plugs in went out still the same ? strip down again stand looking and id letf one of the inlet rubbers loose not even finger tight sorted it and its about sorted it now jsut gonner runn some fresh petrol through

lewisdale wrote:try new plugs, check ht leads and caps, drain the tank and refill with fresh fuel, you set the mixture right?

its had new plugs, coils and leads and its been through 5 full tanks of shell v power and a bottle of redex and still no better and the pilot screws are confusing set them any more than 1 and 3 quarters out and its way to rich and the exhaust tip goes all black and sutty so they are now set at 1 and a quarter and that seems the best if you do it any less than that the revs stay up for a bit when you rev it as if its to lean but when i had the carbs apart the first time the pilot screw washers wer all mixed up does anyone know which way they go ie rubber seal then washer then spring as they were all in different ways and cant really tell by pics in the manual and ye the inlet rubbers are all intact and tight when you ride it it does seem as if the pilot screws are set to rich but they cant be

on the pilot screws the metal washer goes on spring then the rubber one last, u checked the choke isnt sticking on? checked the plug gaps? how does it idle?

the pilot screws are right then and the choke is working fine and everything in the carbs look brand new it idles fine and revs fine at a stand still but then as as soon as you put it under load it missfires and when you stop it will idle lumpy and missfire if you blip the throttle a bit but if you leave it running for a bout 20 seconds it will go fine again until you ride put it under load again

do the revs hang atall?

wen the pilot screws are set to one and a quarter no the revs dont hang at all

how about when theyre at the standard setting? reseal the inlet rubbers where they bolt on the engine, then set the mixture to standard and try

sorry but what actually is the standard setting so many people have told me so many different things and ill try the inlet rubbers again but im pretty sure its not these and would it be an idea to maybe use a bit of sillicone

yes mate use petrol resistant sealer, unbolt them from the engine,clean up the surfaces thin smear of silicon and bolt them back on, as for the correct setting have a look http://www.zxrworld.co.uk/zxr400/lmodel.html should tell you

right ill give that ago after work tomorrow cheers

ok

tried setting the pilot screws to 1 and3/4 and no better if anything its worse and everything is definately sealed now but if i take the plugs out after a run then number two is black and all the rest look pretty clean would be worth maybe backing number 2 pilot screw off a bit

doubt it will make much difference, what plugs are you using and are you sure you havent cracked the porcelin when tightning them up? ive done that before lol