Commercial restricted GERMAN bike with
-different Carb setting  for 50 HP '85 model & '86 "1WW" model for insurance classes.
-different Carb setting and restricted Exhaust (Parts of metal are welded in the exhaust down pipes reducing the internal diameter from 33 to 26mm) for  27 HP '85 model & '86 "1WX" model for "1A" license.

Restriction for regulation of pollution (standard emissions) with "catalyst" part metal  (in the exhaust down pipes) working with unleaded fuel only for '86 "1WU" Swiss model. Restriction of noise emission with Different Carb setting + restricted Exhaust + a front sprocket with 18 tooth instead of 17 (to reduce the engine RPM) because a noise law need a measurement of noise @ 80km/h. This '86 SWISS RD350F2 1WU model is restricted @ 45HP (33.3 kW) for a SWISS law (perhaps for noise again...) i suppose but i don't know it's done .

In Brazil, all the RD 350 LC/R made 55HP (due to bad quality of fuel so 59HP in Europe) because it had '83 31K cylinders and carburettors without power-jets like '83 31K ones so the engine is close the '83 to '85 European one (they never had '86 engine evolutions).

Restricted exhaust (with restrictions washers in the exhaust downpipes) with different carb setting  for '92 to '95 English, Italian & Spanish "4CE" model (Made In Brazil). I read in WHAT BIKE MAGAZINE from January 95 : "Cynics say the restriction's there in the first place because the worn out seconhand tooling the brazilians use can't turn out engine parts with tight enough tolerances to produce peak power reliably ".

Since '86 (RD350F2; RD350N2; RZ350F; RZ350R...) the 63HP engine dont want to revs over 9500rpm (and the power fall very quickly after 9000rpm) due to carbs setting (too rich), CDI setting, YPVS setting and exhaust; i think YAMAHA do that to have a reliable engine. It's not a real restriction but a conception.