My 125cc ATV auto w/ rev. came w/ a 20mm carb and no air/idle screw, to small, so I found a 25mm carb for 90 -125cc 4 stroke engines, had a black 26mm intake manifold and gold swivel, an hp big cone air filter. To put the twist grip on had to turn the front brake lever from the left to right and the start/kill from left to right, but it works great.
The other 2 photos, from left to right a 19mm, 20mm ATV, 22mm X18, 26mm Mikuni ??, and a 27mm carb and intake for a 200cc vertical engine.