Bike idles, then sputters and dies

[Hazmat6666]

He all, hoping for a little direction.

72 xs2, open pipes, mikuni vm34s (brand new, working to dial them in), with air pods, electronic ignition.

I just put on a set of Mikunis from Niche Cycle replacing the old falling apart (damaged) stock carbs. With the "choke" in, it starts easily, will run on the choke, I have been able to ride it and let off the choke, good acceleration in all areas, low, mid and full throttle.

When I come to a stop it will idle for a short bit, maybe 10 to 20 seconds, then as best I can describe it, it 'ticks' almost like a small backfire or detonation. It will do this for a few seconds, then the idle will all of a sudden slow down and puke out. Also of note, I adjusted my timing chain and valves yesterday (.003 in, .005 ex)

Once this happens I can restart, but I need to use the choke, even though it is well warmed up. If I give it a little throttle blip I can keep it going but would like to be able to stop at a light without fear that I am going to have to kick it over (oh yeah, kick only).

 

[TwoManyXS1Bs]

Sounds like a lean idle circuit.
Have you read the VM carb threads?

http://www.xs650.com/threads/carbs-carburetors.43/
http://www.xs650.com/threads/help-me-id-these-and-can-they-be-tuned-mikunis.6570/

 

[Hazmat6666]

Sounds like a lean idle circuit.
Have you read the VM carb threads?

http://www.xs650.com/threads/carbs-carburetors.43/
http://www.xs650.com/threads/help-me-id-these-and-can-they-be-tuned-mikunis.6570/

I have not yet, though done a bunch of research on youtube with some tuners on there. I will check on the lean thought after another couple ride sessions. My plugs were very sooty from the prior carbs, clearly running rich which I think a little odd given I had a couple sucking air leaks; I have cleaned them up so will see what they look like now.

Hoping to get this figured out in the next couple days, I have a charity ride on Sunday and would hate to miss it because of this.

 

[5twins]

Yes, although pre-jetted carb kits are often close, you'd have to get pretty lucky for them to be perfect for your particular bike and mods right out of the box. I looked up that kit you got and it says it comes with extra different sized jets. You''ll probably need to try some of them. There is an air screw on the side of the carb near where the pod filter clamps on. This controls the idle circuit mixture. Normally it's run at about 3/4 to 1 turn out. Turning it in will make the idle circuit richer so you may want to try that. If you need to set it at 1/4 turn out or less, I'd say you need bigger pilot jets. This air screw is for fine tuning and only has a small, limited effect. To make a bigger change you have to change the pilot jet size.