Engine break-in technique. Have you seen this?

[Alpha Reign]

Originally Posted by Mudflap

The Rotax engines we use in our ultralights have a 1 hour break-in procedure ending with 5 minutes at full throttle. (Prop limits RPM to 6800). After that you go fly.

The old Vespa owners manual said "During the first 1000km or 600mi do not insist with a fully open throttle." Sounds like a good plan to me.

You should always do what the manufacturer tells you to. If you don't and work in aviation you can get in serious trouble. The main point of that is to lube all the parts before you hammer the throttle.

[OneLeggedRider]

Well in school they taught us to put a new or rebuilt engine through 3 heat cycles without lugging or WOT, which is pretty good advice. Now back in my 2-smoke racing days a good friend rebuilt his CR the same time as my YZ, he did the hard break in and I did the soft. I have to say his was a little faster but mine lasted almost twice as long. But it really boils down to common sense. I have a highly modded 01 Polaris Scrambler 400 2-stroke that I take to the dirt drags and it's wicked fast and I've gotten 3yrs out of the last top end. The secret is dont hold it at the same rpm (high or low) for an extended period of time. I realize 2 and 4 strokes are different animals but both will benefit from a varied rpm range especially at break in.

[China Rider 27]

This made the most sense to me.

[timcosby]

what i do to break one in is let it warm up for a out a minute then while still in the garage put a bungee cord on the throttle at full open for 36 minutes. neighbors hate me but it has worked for me.