I'd like to hear about your setup and techniques and line choices if you bass fish w/4lb line

Rod....6'6" Teamdiawa mf Spinning

Reel...2500 Shimano Sharah

Line..Trilene 100% Fluro. I'm trying this line out. Normally I use YoZuri Hybrid Ultrasoft.

Techniques....Finesse fishing, mainly worms, i.e. t rig, and dropshot. One day I got bold and threw a scrounger head..lol  I only fish for Bass.

I have 2 setups that use 4lb. test line. The first is a 7" UL spinning rod with a Mitchell Avocet reel. The second is a St. Croix ML 7" rod with a Shimano Symetre reel.

I use Stren Clear Mono for both. I have some 4lb flouro, but not sure if it helps since the line is so small to start with. If it's clear water and sunny, it might be the answer though.

I really like both of these rigs. They don't give a fish any slack line, and the rods aren't powerful enough to snap the line. You can double the rod over and the line will still hold. It has really helped me to land more fish. I lost alot of small ones because the rig was too heavy and the fish would always get some slack line.

You can lead a fish around all day on one of these rigs and stay hooked up. Use a 1/8th oz. black/yellow eye jighead tipped with a minnow or worm and you will catch plenty of fish. Its almost too easy.

One last thing i do is to tie a 18 inch leader of the same line and tie my lure to it. The reason is because of what is called the "light piping" effect. Sunlight on your line brightens it up under water. With the blood knot connection above the lure, the light traveling through the line stops at the knot and  doesnt brighten the line and makes it less visible. 

I use 6lb yo-zuri hybrid ultrasoft on a  cabelas 6 ft. 6 in. medium light rod saddled with a shimano symmetre 2500. I use it for unweighted plastics, fishing flukes on a road runner rollin runner or martens scrounger head jig.

I know you said 4 lb but the 6 yo zuri has breaking strength of nearly 12 lbs and is still very thin. Seems like the best of both worlds to me.

I totally agree with PondHunter, especially about the "piping" effect. This fenomenon is even more evident when using fluorocarbon line.

As long as you have open water, 4lb line and a long limber rod will land any bass. I sometimes use 4lb fluoro leader while dropshotting (most of the times is 6 lb); the main line being 10lb braid. (6-6 med-light Daiwa rod, 2000 size Daiwa Capricorn).I check my line very often and retie immediately if I feel the smallest nick in the line.

On the other side, i dont think bass is so line shy that you would need 4lb main line consistently.