Were you going up hill or down yesterday? Sorry, Just being silly.
How are you checking your speed? Does the engine start easily, idle good? What fuel mix ratio are you using? New fuel mix, or has it been sitting for a while? Check all of your wiring connections. We recommend you solder those and not rely on the kit supplied plug-in style of connectors. What spark plug gap? Check your spark plug wire connections at the CDI and the plug boot. Let us know if any of these suggestions help.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"