I plan to get the p/s/c for gx2 5rho, what the difference compare to normal go 5port motor?

The older go 5 port is slightly different in timing and exhaust port profile. The GX2 HO has 0,5 mm thicker sleeve top so it works best with its case.

GX2 HO is raspier in throttle response, its an impressive engine.

And I would opt for the 2 needle, not that the 3 needle is bad, just less point to leak if you can get one.

I gave up with my silver go 5 port engine. It seems to flame out/bog down at WOT. had try everything in my experience. I purchasing a new orange go 5port to exchange the p/s/c see how it goes. The compression is solid.

I need advise on others factor like:
1. Conrod free play
2. Bearing
3. Shaft
Will this factors resulted to engine flameout or bog down?

I gave up with my silver go 5 port engine. It seems to flame out/bog down at WOT. had try everything in my experience. I purchasing a new orange go 5port to exchange the p/s/c see how it goes. The compression is solid.

I need advise on others factor like:
1. Conrod free play
2. Bearing
3. Shaft
Will this factors resulted to engine flameout or bog down?

Sounds like you are too lean on top end and the engine is starving once it's starts to run on the high speed jet (the last 10% or so of the throttle range only, due to the long tapered low speed needle used in this carburettor).
Lean bog was quite common with these if people didn't understand the difference between a long low speed needle carb and a short low speed needle carb.

I would suggest you have the following three issues:
Too rich on bottom
Too lean on top
Idle gap too wide.

Set the idle gap at .5mm - no bigger.
Flush both needles.
Start the motor - if it idles too low then lean the bottom end until the idle comes up to a normal speed.

Now do some WOT runs and lean the high speed needle 1 HOUR AT A TIME until the motor performs well with exhaust smoke at WOT.
The high speed needles on the older 5 ports are very, very sensitive. A race tune is around 2 - 3 HOURS in from flush. NOT turns, but HOURS.

Once the top end is set, re-visit the bottom end and tune for a crisp take off.
Then finally - and only if required - set the idle with the idle screw. You probably won't need to do this if the bottom end is set correctly.

None of the things you mention would likely cause flame outs at WOT. Blown plugs maybe, but not random flame outs at WOT. It's more of a tuning issue.
Only other possibility is a weak or dying glow plug, but what you describe sounds like a very lean top end.

If I remember correctly, the silver head GO had carb needle o-rings that would leave shards (I called them worms) in the jet. This would cause erratic running/tuning problems. If you find no other problems with it, it may be worthwhile replacing the needle o-rings and cleaning the carb passage with compressed air.:)

I even swap a novarassi carb but problrm persist

Have you tried fresh fuel ? bad fuel will give you these problems as well.

Yeah. Tried everything with my nitro exp. Now bought a new go G5T and swapped the p/s/c to try from there. Hope i get a confirmation tat the old p/s/c is broken

You swapped carbs and it didn't change.....sounds like you have an air leak somewhere. Double check everything from the bearings to the backplate to the head to the carb...

Guys, after i bought new engine n replace it with old p/s/c, the engine is good to go. The problem is lean bog, need to run with rich hsn. Something like the exhaust is spliting fuel... I think is normal? Any comments?

Your post doesn't make sense, are you mixing new and old motor parts?
put all the new bits back in the new engine ,run it in and start from there, also replace all the exhaust gaskets so they aren't effecting your tune.

Mixing, will install the old p/s/c to old body n tune from there. Guess the carb problem n need to service.

shane, thank you so much. now i do understand fully how this go motor works after owned 3... will get the gx2 in future. thanks again

I tested the go 5port with dragonRC pipe n kinda like it. Whoever have the pipe can try with go engine