Idle speed.

try using carb cleaner or brakeclean, starting fluid will find the leak in a instant. eeven water will find the leak. when you had the intakes off did you look for cracks in the body and what did you use to seal things back up with when you put them on. i use 1104 three bond best stuff for cases and also intakes how did you tighten them down evenly in stages or one side then the other, doing it that way can cause warpage.

barquirt wrote:

Air leak ... yeah, but from WHERE?

Carb boots? Is there some trick to getting a good seal once they are yanked off? They are so thick it seems unlikely I've cracked one. I haven't pulled them from the cylinder head, either. I'm open to some ideas at this point. I suppose I could hit the intakes one at a time with a little carb cleaner or WD40 and see if i get more revs and some smoke (i.e. - the fluid is getting pulled in). Other thoughts?

A little shotgunning --
Ignition timing advancer stuck in advanced position;
Loose clamp holding carbs onto carb holder;
Old hard cracked vacuum plugs on sync nipple;
Crack in carb holder;
Missing or damaged o-ring on pilot air adjustment screw;
Damaged seal at bottom of choke plunger.

Okay to use Armoral or a liitle silicone spray or silicon grease inside the carb holders to facilitate pushing the carbs into place inside the carb holders.

WD40 spray for air intake leak is a good test to see smoke from exhaust as well as rpm influence.
May also use carb cleaner spray, or propane gas sprayed over the area (carb holders; vacuum plugs).

Good Luck!

I think it is end game on this one.

I went through the carb bank again per the manual, re-set everything and then paid attenton and made sure the carbs were seated nice and fired it up. Once the revs went high I started to back down the idle adjuster a few spins at a time. Got the idle to settle nicely. I sprayed WD40 liberally on the intake boots and all points nearby (that weren't hot!) it didn't draw it in. I think I had a combination of a poor seal before and an improperly adjusted idle speed or carb. I let it run a good 5 - 10 minutes on the center stand once I had the idle level set and gave it throttle it behaved nicely. I plan to rig up my carb gauges tomorrow and give them a final check but I think we are back to go here.

Thank you, all, for your advice and for listening. I have really developed a passion for this '77 KZ650 the past few years of ownership. I want to keep her on the road a long, long time!!!

excellent news just alittle patenence is all it took and now your a happy camper just be calm and think things thru and every thing works out in the end.