Break in period RPM?

[robvas]

Different situation. This was a comparison of differing wear in two identical standard engines.

Not sure I'd really compare a Honda motorcycle engine to a Coyote. Too many differences.

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[hoodscoops]

There's always lots of heated debate about hard break in on bike forums.
One channel tested the theory on two new CB250 engines. They ran them in, one by the book, the other run hard, and then stripped and miked the components.
Wear on bearings etc was the same on both, as were pistons. The hard run engine had twice as much piston ring end gap, which they wrote off as not important.
Except, that extra gap meant that engine will lose compression and start using oil well before the other. Increased ring gap indicates premature wear and loss of ring tension.
Which is why I do it by the book. Sunsequent owners will thank me.

What is the recommend RPMs then?

 

[LouG]

What is the recommend RPMs then?

It varies, on my bikes it was initially not to exceed 5 - 6k for extended peroids, on my cars it was usually 4k, I was surprised Ford don't mention it in the owners manual.
I just kept in under 4k and varied engine load regularly

 

[ChitownStang]

First 200 hundred miles I tried to keep it under 5k
After that, not worried about it. Just don’t hold rpm’s at a constant is the biggest thing.
3rd new coyote and over hundred thousand miles on them.
All run like champs !

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