Carbs? Jets? Whats it all about?

[carsounds_dan]

Right, since im stripping the zxr400 down over winter i'm going to want to setup my carbs to match the micron exhaust it has on it.
its the 4-2-1 system and doesnt seem to have a baffel in it.
BUT
i know the same amount about carbs as we do about the otherside of the moon.
so please, someone explain all this talk of jets and needles to me? also anything i'll need to know about the zxr400 carb system and any hints about setting them up.
cheers
dan

[masterofinsanity]

i know about as much as you mate so hopefully someone will fill us both in.

[carsounds_dan]

right,
since no1 seems to know ill post some things and see if that sets things a stiring
basically,
if i wind the throttle on to full quickly (standing beside the bike, so faster than if riding). then the bike will simple stall, when riding its not noticable because you never turn it that fast, but it does bog down a little if really opening it up.
if you apply choke then if has to be done using great feel and listening carefully, as if you just put it on the engine will also cut strait out.
It also stinks of fuel when its been running, proper stinks of it. (exhaust gases, not a leak).


i dont know if its related but i started her up last night before heading to a party and she had white smoke coming from the exhaust. i'd usually say head gasket (its done 36000 miles) but the coolant and oil is fine, no mayonaise anywhere and the power seemed to be there still.

cheers
dan

[masterofinsanity]

white smoke or condensation? with the symptoms you are suggesting could be the head gasket, does your coolant seem to be disappearing?

[Northern ANdy]

combustion of octane releaes 9x more water vapour than fuel is burn't - for full combustion. So white smoke/vapour/steam is only to be expected. The boggyness is because its too lean.

[carsounds_dan]

coolant is fine, so is oil level.
there is no mayonaise and admittedly theres not much fuel in it either :p
i dont know if its had the head gasket changed before, do you recon i should do it whilst i have the engine out?
cheers
dan

[tomzxr400]

if your goin to take the engine out then i would do the head gasket, cam chain and tentioner and check the valve clearences just so you know they are all right for the price tag of the lot its worth doin then you know for sure its ok you can never tell the milage on bikes .
as for the carbs i would do as the h manual says strip them down clean the lot with some white spirit and your tooth brush then blow through with a compressor . check the float heights and seals for wear and tear as for jets its normaly 96" jets with the needles on number 2 and the mixture screws turned out between 1 1/2 and 2 turns before you play with the miture screws balance the carbs and make sure the bike is idling right then turn each screw clock wise till it runs rough then back it off till its smooth again then its a case of playing around with the mixtures and the needle position till it feels right or take it to a rolling road and they will get it spot on