Mikunis won't idle down

yes sir, I had that hooked up the day prior to starting this thread, LOL the engine was used in a lawn tractor puller prior to me purchasing it ,so they were only concerned with full power, I'm wondering if the previous owner didn't opt for the smaller jet needle and when reved produces enough vacumn that even with the slides closed its pulling fuel from the needle jet. Guess I'll be pulling them off again and taking the top apart this time.

It could have quite a radical cam grind in it. This would play with the Idle as well. Lots of overlap will cause a low vacuum down low, sub 1500. It may fall off both the cam and the ignition causing it to stall. Whats the timing at low RPM, and full advance?

Motorhead: I expect if I pull the carbs off again I'll be buying the ball bearings to bench sync them;I'm not sure the bowls on these can be equiped attach a manometer to check the float levels but I'll look, the guys who built this motor have raced Kawasakis for yrs, but mostly at the strip. Thanks

A manometer would be for checking the vacuum signal at the carb holders/ intake manifolds. There would be fittings on them, with caps at the moment. Checking the vacuum between cylinders is part of the set up process. Manometer or separate vacuum gauges.
Float bowls have a drain screw, or just a main jet access?
A vacuum gauge with a restriction to even the pulses can be hooked up even to 1 at a time to see differences in cylinders.
What is the compression of your motor, both cranking pressure and the compression ratio if you know.

Ok I used the wrong term, yes there are caps to remove to change the main jet, but no replacement with fittings for a tube.I have no idea what cranking compression pressure is, its supposed to be a 10:1 engine so not that radical.I just talked to the gent that went thru the engine before I put it in and he said when in the tractor it always idled at 1500 , unfortunately, he had nothing to do with setting up the carburetors, I do understand they were done professionally though.

Well then I'd try to work out the Hot idle first and go from there. 15oo is a decent speed for a motor with upgraded cams.
Try to get the best hot idle possible, giving it throttle to see if it will return. Maybe watch the timing with a light to verify its retuning smoothly.

Ahh good you are still online, hey motorhead could this problem possibly be from the cam timing being off a link in the timing chain?

that is a possibility, have a check and see. It would cause a low vacuum condition, also check the valve clearance while there.

all the valves were 3 to 5 thousandths when the guy who assembled the engine went thru it a month ago, but the way those cam chain is tensioned from the valve cover I could see them bein a tooth off

Can you get the specs from the engine builder and degree them? See if it has adjustable cam sprocket, slotted at bolt holes.

Try this.

Warm the bike up to full temp and then do the same crack the throttle that caused the idle to hang last time. Then pull the choke. Just for a second. If the idle drops back down and stays there then you just have a lean pilot circuit.

Also, spraying carb cleaner in through the air jet and watching it come out the idle port doesn't mean the jets are clean. You have to pull the pilots and spray them with carb cleaner and run a strand of copper wire through it or other suitable cleaning object.

But I don't think its a plugged jet either. I think the pilot jet is to lean. What size jet is in there??

Hey MH the exhaust sprocket was slotted to get the cam degreed in correctly