GSX750ES base carb settings, pipe and pods!

[Motovalet]

So, as zip interest on my Schwantz tribute GSX750ES, I’ve decided to try and get it running sweeter and get it tested so I can ride it for what’s left of the Summer!

The current settings are:-

Main Jet 120

Pilot Jet 45

Air Jet 155

Needle 15D10

Second clip from bottom 

Air Screw 2.25 turns out
 

It starts and idles, picks up but backfires and spits flames at WOT throttle, which suggest to me it’s lean and maybe needs a bigger main or the needle lifting to the last clip? There’s already a shim under the clip so moving it and using the shim is a reasonable lift. The original main jet was a 110 and the rest of the set up on the bike the carbs came from was four into two into one exhaust, open can, same as on my bike but it ran K&N pods rather than the RAMAIR sock filters I’m using over the original airbox inlet rubbers used as velocity stacks. I’m wondering if the K&N’s would be more restrictive on air flow than the sock filters, hence running lean? I welcome all input!!

[Gixer1460]

Unless the symptoms at wot are on the road or on a Dyno, you can't tell what it needs but only going up 10 points it is likely deffo lean - it's a radically different intake & exhaust from stock. And K&N's aren't restrictive! But CV carbs don't particularly like individual pods - duals work better!

[coombehouse]

Often if it's lean, it will spit back through the carb & if there's no air leaks, flames & stuff from the exhaust can indicate it's too rich. Have you considered running it temporarily without any filters just to take them out of the equation. 

[Motovalet]

So, today I dropped the needle circlip to its lowest setting and also put a shim under each, air screw settings now 1 and a half turns out, still using two RAMAIR sock filters over airbox to carb inlet rubbers. Fires up, idles nicely, revs cleanly and no flames, no spitting and no backfiring! All on a bench so subject to real-time later road testing but I’m mildly confident it’ll be better!