Valk Doesn't Want To Run.

[hueco]

It was running fine last time I rode it about 2 weeks ago. Started it yesterday. It sounded like it was running under water. It didn't want to take throttle. It would rev slowly. Like me getting out of bed in the morning. If I held higher rpm with throttle it was smooth. No miss or backfire. If I closed choke while running it would rev up with that Valk vroom for about 2 seconds. Has stinky, burn your eyes  exhaust fumes. But. No smoke. Black or white. I pulled belt cover off. All looked good in there. I drained all the gas and refilled with fresh fuel. I pulled the plugs. They were not wet with fuel. But. Looked 'damp'.  Not dry like a good firing plug should look. I replaced with known good plugs. No change. Desmog about 10,000 miles ago. Edit. It starts right up. No problem. Just doesn't to run. Any ideas are appreciated. Thanks.

[Jess from VA]

My first guess was bad gas.  (but you swapped that out)

I always return to the three basic elements... fuel (gas), air, fire. 

Air cleaner?

Ignition trouble? 

[Jims99]

I would run a strong dose of B12 or Techron In the next tank or two. Maybe open drains on carbs to get out anything sitting in there. It doesn’t take long for the ethanol gas to collect water and clog slow jets.

[Mouthbreather]

Mine did the exact same thing yesterday after pulling and reinstalling the airbox.....Slow throttle response, sounded like crap, and then eventually crapped out.....a quarter of a mile from home, down a hill......We pushed it all the way back.
Come to find out I had inadvertently pulled the vacuum hose off the backside of the petcock when installing the fuel line and shut down the fuel flow.
Probably not the same issue that you have but the issues sound exactly the same....so it sounds like no fuel flow.
But I could easily be wrong.....
BTW.......never, ever, ever pull that airbox off unless you just absolutely HAVE to!  Leaned into THAT punch.

[The emperor has no clothes]

Sounds like clogged slow jets to me.

[hueco]

I always hated that chore.

[gordonv]

Sounds like my bike when the vacuum hoses had leaks. Could start and idle. Any throttle and it would bog down, unless I could get it up into the higher rpms.

Main issue was the one to my petcock, wouldn't stay open.

After I fixed all the hoses this year, I didn't have the WOT (wide open throttle) issue when I tried to pass someone anymore.