Just bought this trx90 for my kid to go jr drag racing. Starts easy, idles smooth, good power through the rpm. BUT if you stab the gas quickly from idle, it will stall, or at least bog badly. It was also leaking gas (float valve sticking), so I bought a Chinese replacement carb. It fixed the leak but not the stall. Tuned for best idle, good plug, checked for air leaks with carb cleaner, fresh gas, does it in neutral or in gear. I have searched and found lot of similar issues, but no confirmed fixes. Need to get this figured out as drag racing will be hitting the gas hard from idle.

 

Check valve adjustment and compression.

 

thanks for the reply. I did the valves today... they were both fairly tight (1/4 turn to get them to 0.002”). It didn’t fix the issue, but its a bit more clickity. I also checked leakdown- 96ish, so the should be ok.

anything else?