Revving Weirdness - Phase II

So, my 76 KZ750 hums right along now after a long battle with it revving waaaay up. I'm not out of the woods yet because there are symptoms still. I'll just list them:

• Bike will not start (from cold) with the choke on. Only starts with it off.


• If I turn up the choke after it's started, the bike dies.


• The bike idles steady and at a normal rpm when first running.


• After some riding, the idle will not come back down, even when holding in the clutch.

!
• If I slowly let the clutch out when stopped (and in first) it will allow the idle to come down and if i let it go down far enough (almost engaging the bike) it will stay down, otherwise it goes back up (3000-3500)
• If I put it in neutral it stays up at 3000-3500

My carb boots are sealed off, so I know there's not an air leak there. I adjusted the clutch cable to spec last night. The clutch feels much better but it didn't change the behavior.

I feel like I'm close. The bike runs great otherwise. Any ideas? It's the last big hurdle to riding this summer! :woohoo:

1. Throttle cable too tight holding slides a bit up all the time? There should be just a bit slack between pull and push cables.

2. Could there be something mechanically blocking/preventing throttle linkage from going all the way down? Like carb boot clamps? (happened to me once)

3. Could there be something loose on linkage inside carbs? I mean under top caps? (Also been there seen this...)

Sounds like the bike is too rich with the choke on to start. What airbox/filter are you using? What size pilot jets?

Hrm, good question. The air box/filter and jets are all the standard stuff. Nothing modified or added.

Running too rich seems to make sense. The weird thing is that it runs fine for the first little while. Maybe when the bike warms up (like it should be while the choke's on) it's idling higher (like it would if the choke was on)?

The throttle cable slack is good.

I'll check to see if something is blocking the linkage. Just doesn't seem like I'd be able to ride it at all if that was the case.

Fin, not sure what you meant by "loose on the linkage inside the carbs".

This thing is a few adjustments shy of good.