hello every one my name is chris and i am new on here, i own off road bike it is a cr125r 1990 could be older and it has the atac valve on the front pipe. now the bike ticks over nice but wen you open her up the power band comes on and goes off and sounds like she spluterin a bit and it does not have anythin on bottom of the atac valve could that be the reason if any 1 could help plz