250 N/C cyl head refurb

[Bevel bob]

After a rebore ,too much idling will glaze the bore. Also a too slow idle will starve the motor of oil. Give it some shortish bursts of work to set the rings. Once run in keep the motor spinning well . The big end will thank you.

[Mike]

Thanks Bob - how my brain interpreted that...

Don't waste time letting it idle, get out there and ride the nuts off it

[themoudie]

Aye Mike

Yes, as Bob suggests, keep it spinning 5,000rpm ceiling and not lugging. 20W-50 oil for 20 - 50 miles, then dump it and check for "sparkles"! Run a magnet over the drainings as well. I flush the sump out, using aerosol brake cleaner, with the machine on the sidestand to drain, and let it evaporate, afore refilling, with more 20w-50. Change oil again at 200 - 250 miles, same clean down and check, refill with 20W-50 and run to 1,000 miles, with short bursts of max revs (8,000 - 9,000rpm). Now drain and flush, then fill, with your regular running oil of choice.

My 450 didn't really free off until after about 1,500 - 2,000 miles of running.

Good health, Bill