Given the insensitivity of the engine to the needle valve, and the fact that the engine won't rev up to full throttle, there is probably a small chunk of crud caught in the HS needle valve. Take the lines off both sides of the needle valve, hook your fuel pump up to both sides such that you can pump fuel backwards through the needle valve. Back the needle out until it just barely stays in the threaded portion, then pump a few ounces of fuel through the needle valve to back flush it. Filter it if you're sending it back to the fuel jug, then clean out the filter.

Now put the needle valve all the way in, and back it out about 2 turns. This is a good point to restart the engine, retune it, and check it.

A pinhole airleak between the needle valve and the carb can also cause this problem, as it causes the engine to run too lean, so replace the line between the needle and the carb.

The LA series are pretty tough. No need to tear it down until you've made sure the needle valve is clear.

Also make sure your air bleed hole on the front of the carb is not plugged with dirt or debris from the crash.

Brad