Throttle very sluggish at low RPMs

[Unnamed]

Well, I just got my bike running well and now I'm suddenly having trouble with the throttle. For background, I cleaned the carbs about a week ago, and replaced a rusted choke cable yesterday. With the choke full on, I can start it cold and it'll hover around 2k rpms. Once it warms up and I take off the choke it'll idle about where it should. My problem is that if I twist the throttle I get very little response. It will very very slowly increase the revs up to about 4k, after which it will behave normally. This is of course a problem since I stall the bike while releasingg the clutch because its so hard to keep to revs up. Anytime I drop below about 4k it takes me forever to get back up, even if I'm giving it full throttle.

I'm not really sure where to start on this one. It seems that my choke cable might not be adjusted properly, but I'm not sure if that would cause the problems I'm having. I'm also wondering if my carbs might have somehow gotten fouled since I cleaned them. I've been running fresh gas and I don't think my tank has any rust, but I'm considering splicing in a fuel filter to see if its picking up any residual sediment. I also thought it could possibly be the air/ fuel mixture, but my mix screws are still covered by those brass caps. Finally, I suppose it could be some problem with my ignition circuit, but I'm not sure why it would just show up now. I'm pretty lost here, can anyone give me suggestions on what to look at or what tests to conduct?

[scratch]

I can help with eliminating the potential sediment problem: Drain the floatbowls a little into a clean container.  Lots of big flakes=bad; shine flashlight into gastank.

[Affschnozel]

If your choke cable was rusty then maybe the throttle cable needs adjustment+lubing also.
Does it feel that the cable sticks when you apply throttle?
When you hold the throttle open does the rpm stay stable or fluctuates?
Most likely the choke cable is the culprit so try adjusting it
Could be an air leak also...spray WD-40 around carburetors while bike
is running and look for white smoke from exhaust

[red_phil]

I had sluggish throttle response when the engine was too rich. I'd put the clip on the carb needle in the wrong groove.
After I fixed that it was ok but a bit sluggish. Last week I syncronised the carbs. The throttle response in now MUCH better.

Easy enough to try out.
Take the tank off.
Make a small tank. I used a sports drink bottle with a spout of the right diameter to fit a fuel line.
Run the engine for a few minutes until it's warm then adjust the idle up to about 3K RPM.
Now use a screwdriver to tweek the balance screw. it's the cross head screw on the bit where the throttle cable atrtaches to the carbs.
Try one way then the other and see if the revs rise. Find the position at which it revs highest and your done.

I did a proper balance with guages but I really could have watched the RPM. It revved highest when balanced.