Topic: Engine break-in ... Is this flame bait???

[RAFster122s]

Almost as bad as an oil thread to some...
Hopefully not too much flame bait.

Engine Break In experiment

[Kevin]

That was interesting.
When I rebuilt the engine on my CB400F I installed FCR carbs.
I did not know how to tune them so a friend of mine came over to do it for me.
He races CB400F's in Japan and is very familiar with the FCR's.
I was horrified as we raced the highways between Tokyo and Yokohama pulling over at rest stops so he could swap out a needle or make an adjustment.
But I let him do his thing. In the end he had my engine purring at idle and an absolute monster at WOT.
It was a cool experience and one I will not forget.

[BomberMann650]

The quality of the rings and a proper hone makes the difference.

Honestly surprised they didn't mention the cylinder assembly process.  As the debate rages between lubed and unlubed piston fitment.
I'm of the inclination that lubrication in the right places matters (i.e. the skirt) Using too much in the wrong places (i.e. the walls and crown) is reported to be a problem for initial ring seating.  A hone that is too rough or too fine for the type of ring and application can cause premature wear as well.

All things considered, flogging a new top end on the dyno will help find any potential problems faster

[HondaMan]

While I don't know ALL engines, I do know the SOHC4 engines well. What I've learned about the break-in is:
#1 Don't skip the 300 mile oil change.
#2 pretend the redline is 5000 RPM until 300 miles, and 7000 RPM until 1000 miles.
#3 change the oil at 1000 miles.
If these 3 things are done and the engine was built properly, you'll either get tired of, or die before, your SOHC4 engine wears out.

I've also learned this about them:
- not changing the oil when needed will wear out the (non-Stellite or non-bronze) valve guides, quick, while the rings can survive it.
- riding at high speed for days on end makes them run better the next day. EACH next day (and faster).
- they like to be clean.
- compared to other bikes (and cars) I've had, these can be boringly reliable. Don't let that make them boring: enjoy the lack of forced maintenance, instead.