2000 XL800 issue no accell over 4k intermittent

[Spidaso67]

PO rebuilt motor a carbs, ran great through break in and the next 10 hours. Now it has developed an issue, comes fine out the hole but won't go over 4k, fiddling with choke or accelerator might get it to burst up to 7k for a second, if I shut it down and pull the fuel line off the filter, let filter drain and run it out gas, hook it back up it runs fine for 30 or so minutes. After that it starts bogging at 4k, rinse and repeat.

Any ideas? Thanks!

[butterbean_29512]

Check your tank vent, make sure its not sticking closed.