yamahatzr50

well i believe something was removed from the exhaust...i didnt get it brand new but a few years old...im TOLD there has never been any real problems with it

ive checked there is 2 stroke oil in the tank no problem and i have also cleaned out and re filed the engine oil...thats why im soconfused it isnt on right now but it will come on only when i rev

i have a yamaha tzr 50 which has been derestricted recently it has been cutting out after riding for about 5 mins then keeps doing it...i have had it apart and cleand out the carb fuel tank and such which went fine for about 3 days then same problem she cuts out i roll with her thwen she dies lights go out but the dash lights stay on i did notice that when i revved the oil light gets brighter depending on how much i rev....so i did it again and just 10 mins ago i went for a ride and if i try to for example kick it into 3rd gear she sounds horrible and wont go above 50KM she does do 90km max so yea then it feels like someone slammed on the breaks and i begin to slow down but i can stay at 50 if i keep in it 2nd gear so any ideas about the first problem and maybe the first problem vcaused the second one...thanks in advance for ur advice edit...i have also changed ghe spark plug i read about the ht lead but would that really cause these probems and she feels like she is wobbling a bit ont he road