Check all this stuff:
1. Air filter should be clean
2. Carbeurator jets should be clean and air fuel mixture should be set perfectly (not too lean slightly rich is good for speed)
3. Spark plug should be oem ngk and spark plug gap shocks be within spec.
4. Tappets should be properly adjusted using feeler gauge (local mechanic don't use feeler gauge).
Minor things (use thinner oil 10w30 , use iridium spark plug, clean and lube your chain)