Depends
if he does other ups like a zorst and 1/4 throttle will be fine
i can run a 26 with zorst on my 110 and is fine
carb
OKO VM26 Performance Carby Kit - DHZ Mini Moto
Zorst
Big Bore Alloy Performance Exhaust System 125cc 140cc CRF50 - DHZ Mini Moto
Throttle
Aluminium 1/4...