Cutting out at cruise

Hey guys, cleaned and rebuilt carbs. 1978 LTD1000, VM26 carbs, pods and a kerker. 15 pilot, 113 main, needle in 2nd position {from bottom}. Carbs synched up nicely, fuel screws @1 1/2. Idles perfect, accelerates nicely all the way through. The issue I’m having is I can cruise at 35 mph seems fine, get out in the freeway and at cruise speeds 55-70 mph runs rough like its cutting out or like it’s dropping a cylinder or something . Gas it and it goes like it should. I would like to say it ran fine before but I’ve had this thing for a couple years and honestly can’t remember if it ever ran perfect. I bought another set of carbs and they ran very rich with the same set up. Any thoughts?

Nobody ever experienced this? Going to mess with fuel screws i guess. Right now they are all the same. Thought maybe spark plugs but that doesn't seem logical given that it runs great other than at that small throttle section. Hopefully I can get some input. 

Fuel screws really only are effective at idle. What needle is in the carbs and what clip (if grooved)?  You may want to search on here for “air adjuster jets” or something like that available from Zed1015, I believe.  They may help out the part throttle surging.

Later, Doug

   Is fuel level at factory spec +/- 1mm?

Good Ridin'
slmjim & Z1BEBE

Well according to the tube method it is. Has to either be that or a needle issue I would think. Ill recheck float levels, which I assume you are referring to. Thanks for the insight.