500 ft elevation, added 125/40 jets, 2 #3 washers, float height set to 15mm, set to anywhere from 2-3.5 turns (no big change) and now it idles a little low/rough and has a hard time coming off idle. Once the it gets up a little it'll pull hard ok, but occasionally it sputters/bucks pretty good on its way....

Any ideas? I'm about to go pull the second washer from the needles and reset the idle jet screws to be sure.

Well the removing the second washer helped, idle seems decent, but it's still very stumbly when on throttle anything below 3500 rpm...this is why I went to all the trouble of replacing the torn carb boots, loosing the vacuum petcock, and jetting it to 125/40...damn this is frustrating. I just want to go enjoy my damn bike...I had less issues with my '77 KZ400 with mods, stock jets, and a torn carb boots...HELP!

Im having a similar problem. I've got a full exhaust and an intake, and I've a serious flat spot at low throttle, even after cleaning out the pilot jets.

Its most noticable shifting into 6th under normal acceleration. Something like *shift* *apply throttle* *boooooooogggggggggggggggggg* *ACCELERATE*

I'll let you know if I find any solutions. I'm thinking I need a good, more thorough, cleaning, a sync, and a proper fuel screw adjustment.

are you saying that you have the idle screw on the max high position and it idles low? just to clarify, no insult intended by the way, the idle screw is counterintuitive (to me any way) clockwise is lower idle and counterclockwise is higher idle. so you have turned it fully counterclockwise and it still idles low?

Sorry was talking about the idle adjustment knob being all the way snugged up (i.e. fully open). After resetting the idle mixture screws to 3.5 turns out, it seems to be MUCH better, but is still a little rocky/inconsistent below 3k RPM. Would 4 turns be too much?

Any ideas?

if its fully open it should idle at over 3000rpm. if yours is indeed fully open and its idling low then you have a problem that mix screws cant fix.

It's all sorted now. After pulling the needle washer and resetting everything a 3.5 turns it's MUCH better. It's still has a weird weak spot when cruising below 3k RPM (which is rare). I rode it to work today and it was great. In town cruising rarely allows me to hit that weird spot.

Just remembered one of the needles was a bit bent on the end when I removed it early on, I straightened it out, but I'm wondering if it's hanging up a bit casing this issue.

Any idea?

a needle sticking open could cause low rpm problems and hesitation due to friction. I would replace it in any event.

That's the plan. Thanks for reaffirming things.