Running in after a crank (only) rebuild

[itiejim]

I'm aware of all the excellent advice surrounding running engines in after a full rebuild to ensure pistonring seating etc. However, I have a Triumph 2500 lump which has only had work to the crank - a full regrind and new mains and big ends.

Is there any specific advice as how to proceed with this - and for how long?

Many thanks

[GavinPearson]

Use no more than 3/4 max rpm and change the oil & filter at 1000 miles, then 3000 after that.

[itiejim]

Thanks Gavin. Is that rev limit just for the first 1000 miles?

[Pumaracing]

I have to strongly disagree. There's absolutely nothing that needs running in or taking easy with a properly assembled crank and bearing shells. Running in is primarily about piston rings and bores. The crank and shells don't even make metal to metal contact once the engine has started never mind abrasive contact like piston rings where high spots do indeed need to be worn down.

The engine can be driven as normal from the start.

[itiejim]

OK, thanks for the advice - and the logic behind it. I'll go for some normal, gentle running for a couple of hundred miles and then drop the oil.

[Pumaracing]

There's no need to change the oil. There's nothing to bed in or wear off from the crank shells. If anything significant enough did even wear off from them to warrant an oil change they'd be toast by then already and it'd be rebuild time again.

[itiejim]

OK, thanks