Engine break-in

[Timetrader]

Im just finishing up a complete top end rebuild on a late model evo engine,Im interested in hearing from those in the know about breaking in the engine,heat cycles,ring seat,etc...Thankyou,Tt

[JW113]

Oil Thread Alert!




Here we got the typical opinions and a-holes discussion. OK, I'll bite. Here's mine.

Short heat cycles after first fire up. A few minutes... then add a few more.... then add a few more. The point being to wear all the un-subtle edges from the cylinder walls and rings but not overheat them. Then, it's time for short rides around the 'hood. A couple miles...then five... then ten...
Once ya got 25 or so miles on it, time to get on the highway and do 2000 to 4500 rpm full throttle pulls, ten in a row. Then... ride it like you're gonna ride it.

Works for me, not for everybody. Doing it on a dyno is preferred by many, but I don't have one.

-JW

[Burnout]

The biggest concern is to avoid heat, creating hot spots or galling this is the reason for the start it up and shut it off deal.
Don't slow idle it, it want's plenty of oil thrown up on the cylinders.
Be nice to it when you ride it, don't rev it up a bunch or hold the power on for very long.
At the same time you don't want to putt it as that may cause a poor ring seal.
So go ahead and hit it, make some power this forces the rings against the cylinder and promotes a good break-in.
You can incrementally increase RPM and temps as you progress.
By the 50 mile mark you should be riding normally.
Change the oil 50-100 miles again at 500, CHANGE the OIL & filter HOT!
You did clean the inside of your oil tank first didn't you?

Have a good handle on the spark and carb so its ready to go when you first fire it, makes it much easier on the motor and you.

[Timetrader]

Yeah,i hear you folks on the opinions thing,i knew that when i posted,but there is some good knowledge here,so i asked,as far as the oil tank,prior to disassembly i drained the oil,then reinstalled drain plug and added 3 quarts of oil,then with the oil filter removed,i fired up the scoot and let the oil funnel into a pan while adding new oil to the tank at idle,i ran 3 quarts through the system this way to flush,is this good or should i flush the oil tank with kerosene/oil,Thanks

[Hillside Motorcycle]

3 heat cycles, bringing the cylinder temps to 150-160 degrees, then ride it 3-5 miles loading the engine in the lower gears, not exceeding 3500....then tune it on the dyno.
Done.

[kd]

   I would also add I use a good lighter oil like Rotella 10-40 for the heat cycles.  The short 3 to 5 mile ride includes power on and decel religiously until up to temp.  A full cool down of core temp period at the turnaround point and a similar return trip home.  That provides 2 up to full temp cycles that include accel and decel for ring seating in combination with cylinder growth from cold to hot.  I believe the temperature cycles are very important and provide real life expansion and contraction changes.   I dump the oil and filter (checking for contaminates) and refill with a good dino 20-50 oil.  To the dyno for controlled AFR setting and tuning (if the later is required).  Tuning will put on several miles and my next oil and filter change is at as close to the 50 mile mark as possible.  Refill with the oil that you intend to use including syn if that's the choice, and ride it as intended. I will do another oil change at 200 to 500 miles as convenient.  It's as ready as it will ever be and will fall into regular schedule service points.   

[Timetrader]

Update: prior to initial start up,i dropped the oil pan on this scoot and did a thorough cleaning of some sludge, considering it had close to 100k miles the pan was really not that sludge filled,modern oils i guess,Thanks Burnout.I took some other ideas shared in this thread and am happy to report 1000 plus miles on this rebuild,oil changes at 50,500 and 1000 miles all looked good.i dumped oil and opened up wix 51215 filters,no metal chunks.Did a hot compression test at low 170's front and rear, and a cold compression test high 160's front and rear.Rings seated,tuned the cv40 and shes runnin like fine,i predict a lotta smiles per hour in my future,see you in the wind,tt

[Don D]

  I would also add I use a good lighter oil like Rotella 10-40 for the heat cycles.  The short 3 to 5 mile ride includes power on and decel religiously until up to temp.  A full cool down of core temp period at the turnaround point and a similar return trip home.  That provides 2 up to full temp cycles that include accel and decel for ring seating in combination with cylinder growth from cold to hot.  I believe the temperature cycles are very important and provide real life expansion and contraction changes.   I dump the oil and filter (checking for contaminates) and refill with a good dino 20-50 oil.  To the dyno for controlled AFR setting and tuning (if the later is required).  Tuning will put on several miles and my next oil and filter change is at as close to the 50 mile mark as possible.  Refill with the oil that you intend to use including syn if that's the choice, and ride it as intended. I will do another oil change at 200 to 500 miles as convenient.  It's as ready as it will ever be and will fall into regular schedule service points.

Agree 1000%
Couldn't have said it better.
I start them at a high idle for more splash. A few heat cycles only then slightly warm hit the road easy, or dyno and just tune low throttles. Load and unload. Not my method, what i was taught 50 years ago from Hastings.