This may have been posted before, but i have a intermittent Carb cough, on my FXLR.
Engine has had a rebuild, new oil seals and exhaust valves. Bores are great, and runs really well.
Fitted a 2 into 1 V&H, and rebuilt the CV carb. Starts first time. Still kinda running in the new piston rings, so its not had any real hard riding.
Did 200 miles at the weekend, and it pulls well, getting about 50 to the gallon.
Here,s the annoying problem, sitting at 70mph on the motorway there is a occasional cough
from the carb, it feels like its running a little lean. When you twist the thottle it responds with no lagging in accelaration.
So far i have resisted going over 80mph, as i have only done about 500 miles since the build.
Does also pop in the exhaust when slowing down through the gears.
I have the idle set at about 900 until the engine loosens a little more, but it does tick over nice.
Am i just being picky, or does it just need "fine tuning" as the rings and valves bed in.

 

At that speed. It needs some more fuel off the needle, try dropping the clip ,

 

If you have the stock needle in there get an '88 sporty needle and put that in there. CV's transition around 2,500 RPM's and you are probably just over that at that speed and the sporty needle will fatten it up there. Also check the diaphragm to ensure it is in correctly and no holes or tears.

 

As above.

 

Plus one on MIA and GSXR's posts. I always have a couple new Sportster needles in my carb parts same as having at least one each of pilot and main jet sizes. Never know when you're going to need one (usually for someone else's bike).

 

^^^ H-D Part No. 27094-88