2005 Road King Acceleration/slipping Issue
 

Did you install a new spring?

When you change the primary oil, is it dark?

Any engine mods that might be overpowering the stock clutch?
A slipping clutch will turn primary fluid dark pretty quickly.
New clutch springs are pretty cheap and easy to swap
You say it otherwise runs fine
Stripped splines or belt would probably have put you on the side of the road waiting for tow I would think

Clutch spring is new and the adjust bolt is exactly 3/4 turn out. The clutch oil was not dark at all, it looked really good. No engine mods, it's stock. I'm surprised I'm the only one since 2005 that have ever had this problem, please help this is ridiculous.

Here is are some things to think about.

1. does it slip in higher gears?
2. When is slips do you hear / feel a grinding?
3. What clutch kit did you use?

Generally if some thing like a chain, belt or comp slip, thet make a grinding sound. Stripped splines generally simply pop.

did you install the clutch yourself and get all the friction plates laid in the basket in the correct order ?
if my memory serves me correctly each friction plate (fabric on each side) lies between two smooth metal plates.