ninjette.org - View Single Post - What’s my break in period for a new piston?

jkv45 · August 13th, 2018, 10:11 AM

Break-in is more for seating the rings than anything to do with the actual piston. To seat the rings you want cylinder pressure. That means load. Moderate loads with a variation in RPMs is usually recommended, as is some heat-cycling.

I've been told by a high-end (Porsche, Ferrari, Nascar and NHRA experience) engine builder that extended break-in time isn't needed if the machine-work has been done properly. He said oil isn't critical (synthetic isn't any more "slippery" than conventional oil as long as it has the correct additive package - no "Friction Modifiers"), but he likes to change it fairly quickly after the engine has been run a while (complete rebuild, after running maybe an hour). So just run an inexpensive conventional oil that's motorcycle compatible like Rotella T. Don't run any automotive oil in a cycle engine.

That's pretty much in-line with what I thought, but there are many opinions on the subject.

August 13th, 2018, 10:11 AM	#9
jkv45 Rev Limiter Name: Jay Location: WI Join Date: Jul 2013 Motorcycle(s): '06 SV650n, '00 Derbi GPR, '64 CA77 Dream 305, '70 CL450 Scrambler, numerous dirt bikes Posts: A lot. MOTM - Jun '18, Oct '16	Break-in is more for seating the rings than anything to do with the actual piston. To seat the rings you want cylinder pressure. That means load. Moderate loads with a variation in RPMs is usually recommended, as is some heat-cycling. I've been told by a high-end (Porsche, Ferrari, Nascar and NHRA experience) engine builder that extended break-in time isn't needed if the machine-work has been done properly. He said oil isn't critical (synthetic isn't any more "slippery" than conventional oil as long as it has the correct additive package - no "Friction Modifiers"), but he likes to change it fairly quickly after the engine has been run a while (complete rebuild, after running maybe an hour). So just run an inexpensive conventional oil that's motorcycle compatible like Rotella T. Don't run any automotive oil in a cycle engine. That's pretty much in-line with what I thought, but there are many opinions on the subject.