The TLE43 has a stock two-barrel carburetor and filter with no adjustments except idle speed.
I installed ADA S1 expansion chambers on both engines of The Dragon Lady". They could use better-performing carbs and air filters to make use of their improved exhaust.
The front engine bogs a little at maybe 8000rpm. It has 39.37" of rubber exhaust tubing connected to the bleed port. The tubing connects to the silencer/muffler strapped below the frame near the crankset. The smole would blow directly into my face, so I had to reroute the front engine's fumes.
The exhaust tubing is so effective at silencing the engine that most times I disconnect it from the muffler.
The rear engine has the normal silencer/muffler connected by four inches of rubber exhaust tubing.
I was referring to the Walbro # on your stock carb (it's on the side)
There are a few options.
1. WYK-58 is great, barrel carb, high/low/idle adjustments.
You might have to make an adaptor plate to line up the pulse hole.
2. WT-603 or 668 (almost identical), h/l/idle but this is a butterfly carb.
Both would be optimal for that motor.
I use both on my 39-50cc 2 strokes, and they do very very well.
You just have to learn how to tune them well if you don't know how,
or you'll be in big trouble.
The butterfly version has a bit more throttle response,
and on the WT series you can tap a fitting into the bottom plate of the carb and engine's cases to do an external pulse line,
which makes lining up a pulse hole on the mani's a moot point.
Like this...
http://www.capturedbyrobots.com/images/603cagped.jpg
Bogging is dangerous on this motor without a tunable carb.
You are most likely running very lean at WOT.