While the RZ350 was sold in the US,to comply with standard emissions (controlled by EPA: Environmental Protection Agency) , it was equipped with dual two stage catalytic converters inside the mufflers (for the FIRST time in the world !).
 

		MICROFICHE OF THIS SYSTEM
d		AIR FILTER
		REED VALVE REGULATION
		CATALYTIC CONVERTERS (Coated with platinium-metal catalyst).
Legal marking stamped on both pipes !
Fuel tank filler have a restricted diameter to only accept unleaded size nozzles.

 

Standard pipe

Catalysed pipe with heat shield

This catalyst is a device to complete the combustion process begun in the cylinders but left incomplete by the nature of the (2 stroke) engine: A reed-valve opens when pipe pressure falls below atmospheric, admitting filtered air to each pipe.When unburned hydrocarbons (HC) and carbon monoxyde (CO) encounter this oxygen on the surface of this catalyst, they combine just as in burning; turning these smog-producing compounds into harmless water (H₂O) and carbon dioxide (CO₂).

This device works (only with unleaded fuel) from 750°F (400°C) to 1650°F (900°C). If temperature exceeds this value, warning light & buzzer alarm turn on and the bike must be stopped.
Carburettors with the 2 throttles commanded by 2 linkages connected to a pulley (and 2 push and pull cables: push to close and pull to open the throttle) for USA models and some Japanese models ("desmodromique" system). The cover of the carbs are not screw but held on by 3 screws. The two carbs are bolted together with two brackets. They have non adjustable jet needles, and only the geniune needle jet is available in order to owners don't adjust carbs setting for the good works of catalyst system to respectect the pollution level authorized by the EPA
The '85 NC & NC2 ("C" like California) models have a third catalytic element in the headpipes and, an internal venting of the gas tank and carbs by carbon cannister (sticker on the bike) wich reduce the fuel tank capacity because emissions laws are different in California.

16 years later, BIMOTA use a catalytic system on their '00 500 V-due EVOLUZIONE model to be OK with standard emissions (engine with carburetors).
The '97 500 V-due model (with fuel injection & without catalytic system) works very bad and was a failure...