So since I’m running a PRD in this weekend, I’ll post the instructions they give. They’re way more intensive than what people have suggested above. 45 minutes and at least 3 break in sessions.
3.1 Ensure the engine is mounted to the chassis correctly, all mounting bolts and nuts are tight and the
drive chain is correctly aligned with the correct tension. Check all electrical & fuel line
connections are secure.
3.2 Ensure that the accelerator cable is correctly fitted and adjusted and the throttle valve in the
carburetor opens and closes correctly. For starting set the walbro high & low speed needle jets to
turn 1/2 HI & 1-1/4 LO.
3.3 The 45 minutes run-in period should be divided into 15 minutes periods.
3.4 Do not at any time allow the engine to overheat. If the engine shows signs of overheating abort
the session and allow the engine to cool down. Check for any obvious cause of overheating
before continuing. To excess heat may have simply been caused by an overlong on-track session
or incorrect carburetor setting.
3.5 TRACK SESSIONS 1 & 2:
Do not allow full throttle for prolonged periods. Round the engine in short bursts between 1/2 to 3/4
throttle. Do not allow the engine to labor nor remain on a constant throttle opening for any
prolonged period if using a tachometer limit engine RPM to 7500 [1/2] to 9000 [3/4] maximum.
3.6 TRACK SESSION 3:
Gradually increase throttle opening from 3/4 to full for short bursts full throttle can be used for
longer periods in the 4th & 5th sessions if using a tachometer limit engine RPM to 11,000
maximum when using full throttle.