I have replaced many parts with common bicycle parts. I installed Rockshox forks, a nicer adjustable stem, nicer alloy bars, better quality brake levers, better quality rear brake calipers and pads, and nice Schwalbe Magic Mary tires. I have two 2019 Phatmotos and have completely reworked the drive train also. One version uses the original clutch modified to engage at higher rpms, the original primary chain, a freewheel primary driven sprocket, the original secondary chain, and a CNC aluminum secondary driven sprocket. The second drive train is belt driven. I used a Grubee clutch and freewheel sprocket typically on a HS142, The clutch has been modified to allow higher rpm engagement. Both bikes have different secondary drive sprocket also. Between the major gas bicycle parts suppliers, and electric bike parts suppliers anything you need can be found. I also used a GX100 clone carb for better tuning on one bike and a modified HS142 carb (same size) for even better tuning on the other.