gs550 / 673 final jetting need advices

[boris.h]

hi all!
ok i am ending this.project. i need some advices on main jets choice:
velocity stacks
bandit header with open exhaust
ported head
bs32 carbs with mixture screws at 2 turns.

currently i have 165 mains with the needle at the last notch (the richest). i have no bogs at all and the bike rides smooth. but when i do wot starting at 2000 rpm or lower the bike accelerates but i can feel some bogs as the bike is too lean even the bike do not sputter at all. the bike really start screaming past 4000 rpm. i have 170 mains, do you think that i can put them and go one notch up?

at wot the porcelain of the plugs is a bit.white and the electrode is grey / brown.
moreover i put wot and, if i decrease a bit the bike seems to accelerate more.. what do you think about? thanks a lot!!

[Guest]

Typically if closing the throttle at high rpms actually makes the bike pull harder that is a good indication that the main jet is to small. When you close the throttle slightly you are reducing the amount of air entering the intake but momentarily the same amount of fuel is entering the intake, thus the mixture is richened for a brief second and if the bike pulls harder - your mixture is to lean. Try the 170 mains. If the bike pulls hard in the mid range (4000-6500) dont bother adjusting the needle jet until the main jet is correctly selected.

[boris.h]

ok thanks. yes i find it a bit lean but I was affraid going directly to 170 would go too far

[Guest]

It might be, 167.5 would be ideal but hey if you already have them then all you have to lose is time.