yes but that is true on higher level for two strokers..
Carbon % was high in non euro II bikes, but bikes like CGE2 and paiggio and GS150E2 they have a device externally added to engine to reduce carbon% in exhuasted gases so I dont expect at all a sluggish tar contminated silencer from abrand new CG at all carbon is there in exhausted gases but the E2 device adds more air into it so that carbon % is reduced so longer life of silencer and less polluion in air.. as I showed you pics of piaggio it was mint clean even after exhaustive useage ... thats how a CGE2 exhuast must look like...
Apki bike ya tu zyada petrol kha rhi hai, ya phir your plug has gone bad, or your bikes tappets are too tight get it checked if every thing is fine then engine has to be checked for compression... I hope that would not be the case.. InshAllah
hope that helps