Well, if your carbs are out of sync, it's not going to idle well, so, since that doesn't take very long to do, I'd try that first. If that doesn't clear it up, it sounds like you might be a little bit lean at idle. You might try richening the mixture screws 1/2 turn (counter-clockwise). Remember to re-sync the carbs after any carb setting modification. (the RPM hanging up a bit after the throttle is "blipped" is a classic symptom of a lean idle circuit). "Popping" is usually from "lean-induced backfiring." Is it popping when riding at high revs and then cutting the throttle or is it popping when the bike is in neutral and returning to idle from high revs?


The following is taken from the Factory Pro site... the full write-up is here ( http://66.47.68.116/tech/carbtune,CV...m_engines.html ). It was written to accompany their jet kits, but it holds true for completely stock applications and is actually a great description of how to properly tune a CV carb.

From the Factory Pro site:

Fuel Screw setting (AKA mixture screws)

There is usually a machined brass or aluminum cap over the fuel screws on all but newer Honda. It's about the diameter of a pencil. Cap removal details. Newer Honda carbs have no caps, but use a special "D" shaped driver, usually supplied in the carb recal kit. We do have them available separately, too. 800 869-0497 to order -



Set for smoothest idle and 2nd gear, 4k rpm, steady state cruise operation. Set mixture screws at recommended settings, as a starting point. For smoothest idle, 2nd gear 4000 rpm steady state cruise , and 1/8 throttle high rpm operation. (pj tuning information)

Pilot fuel mixture screw settings, float level (but, you've "fixed" the fuel level in Step 3 - which you have already done!) AND pilot jet size are the primary sources of mixture delivery during 4000 rpm steady state cruise operation.


If lean surging is encountered, richen mixture screws (turn out) in 1/2 turn increments. Alternative pilot jets are supplied when normally required.

Pilot fuel mixture screw settings, float level and pilot jet size also affect high-rpm, 0 to 1/8 throttle maneuvers. Too lean, will cause surging problems when the engine is operated at high rpm at small throttle openings! Opening the mixture screws and/or increasing pilot jet size will usually cure the problem.


NOTE: A rich problem gets worse as the engine heats up.


If the throttle is lightly "blipped" at idle, and the rpm drops below the set idle speed, then rises up to the set idle speed, the low speed mixture screws are probably set too rich: try 1/2 turn in, to lean the idle mixture.


NOTE: A lean problem gets better as the engine heats up.


If the throttle is lightly "blipped" at idle, and the rpm "hangs up" before dropping to the set idle speed, and there are no intake leaks and the idle speed is set at less than 1000 rpm, the mixture screws are probably too lean: try 1/2 turn out, to richen mixture. Be sure there are no intake leaks and the idle speed is set at less than 1000 rpm!

 

Oops... sorry...
Yes, when I said "hanging up" I did mean "stay a little time" before dropping to idle... this is a symptom of LEAN idle circuit... not rich idle circuit as I said in my post... had a momentary brain lapse there. I'll correct the previous post... Sorry for the confusion

It sounds like you may be a little bit lean, but as you know, PAIR can also cause some backfiring and since your idle is erratic, it sounds like your carbs could be out of balance. If it has been a while since they have been balanced I'd start with that and see how it runs. (Adjusting the mixture screws is a bit of a pain without a special tool... requires carb removal).

 

well, It's really hard to say based on a text description... The idle hanging up and popping are both signs of a lean circuit... the probelm getting worse when the engine is hot or the choke is pulled indicates a rich mixture.... so it looks like you've got some experimenting to do. I've had past experiences where all the signs pointed to the bike being lean when in fact it was rich... Basically, what makes the bike run best and produce the most power is the right setting.

can you smell gas in your exhaust when the bike is idling?

If I were you, I'd think about mixture screws after trying to sync the carbs. If they're far out of sync you'll be jetting based on carbs that are out of adjustment and trying to correct a sync problem with jetting... not a good idea.