Running in new parts
A good setup is highly essential!
Make sure you've made the correct engine adjustments:
Jet/spark plug and (always) run on Full synthetic 2T oil!
Running in cylinder(-kit):
The very first time you start the engine with a new cylinder/piston, you must let the engine heat up gradually (low rev's)!
Turn off the engine when it has a temperature of around 50°C to 70°C and let it cool down completely.
When running the engine for the second time, wait for it to get a temperature of around 40°C to 50°C before the first drive.
Easy on the throttle for the first 100km's.
Running in piston:
Let the engine heat up to around 40°C to 50°C before driving.
The first 100km's you have to be steady with the throttle and keep at low rev's. After the 100km's the cylinder will be adjusted to the new piston and you can go full speed.
Running in crankshaft:
The crankshaft (-bearings) are an essential part of your bike and needs to be runned in.
The first 200km's you have to go easy on the throttle.
Important is not to go full throttle and especially not when going downhill!