To me, it sounds like an air correction issue. I've run both an R2J and R5K with the RC Valves pinned open and both ran well, but they both had the correct PGM and carbs for their respective model.
The PGM on every model is "linked" to the carbs, and I suspect the PGM-II with TA20s and a single solenoid just isn't happy. The PGM-II is more sophisticated than many realise, with different maps for each cylinder, TPS input (that not only measures position, but also speed of throttle transition) that alters timing, air correction, and RC Valve operation, as well as being RPM based. The TA20 and TA21 carbs differ internally, despite looking virtually identical from the outside, adding to the confusion.
It may well sound like a cop-out, but fitting TA21A carbs and the correct solenoid setup would be my advice. Without that, you're most likely just going to run around in circles. I'm sure you could make the setup work, but without prior experience, I expect it's going to be a bit of a ball ache! Sorry I can't be a bit more positive, but that would just be me leading you up the garden path, as we say over here!
Edit: Be aware the R2J and R5K static timing [flywheel] is also different, which too will effect the PGM-II operation.
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Andy.
NSR-WORLD.COM
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