Break in conundrums

[Bisbee]

Having some fun reading about different bikes and the break in procedures. My  2017 Stelvio came with a 6500 redline until the first service. MG said to take it easy and vary speeds. OK . The RE Himalayan says to not exceed 30 mph for 300 KM . ??? You could get run over in this country doing that. Some say run it like you stole it. Others say baby it. Who knows? People can get pretty testy over this - almost like an oil war. So, thinking back a few decades, the last air cooled Porsche- 993 had an interesting factory break in. Each engine was assembled by one master mechanic. It took 7 hours. Granted the heads were cc’d and ready to go and all parts were balanced, but he put it all together. One of the reasons that the company would average 50 cars per day - on a good day. Everything changed when they switched to robotics and liquid cooling. But anyway , every new completed engine was hooked to a dino for 30 minutes. For 25 minutes it was run up and down then the last 5 minutes run at redline. 30 minute break in. If it was more than 10 hp under the spec it was returned to the mechanic to be adjusted. Probably cam timing although the factory did state that being air cooled the compression ratio would vary between 10.7 and 11.3. The pistons were matched so they would be the same in each motor. After the car was finished, each one was run at the Weissach test track. Each one was taken to top speed - 172 mph . Turbos higher. If it passed the driver’s critique then it was ready for shipment. Now that’s a break in!

[lazlokovacs]

get it warm gently and then flog it mercilessly.

just my tuppence worth

[John A]

get it warm gently and then flog it mercilessly.

just my tuppence worth

Perfect

[pehayes]

Are you aware that the Guzzi factory is surrounded by an oval track?  I was there on a special tour one day while they were assembling Centauro (Centauri?).  Wish you could see what they do with these machines between assembly line and shipping crate.  Roll off the assembly line and onto a Dyno.  Run it up to speed in all gears with no tie straps and the rider standing on the pegs.  Back off the dyno and hit the track.  Two or three laps and into the crate.  So much for taking it easy on first runs.

Patrick Hayes
Fremont CA

[redhawk47]

The advice I hear a lot lately is along the line of "ride it like you stole it".
One reason given is that the cylinder boring/finishing process is so much better now that if you don't run it hard the rings won't seat properly and the engine will burn oil.
YMMV

Dan

[twowheeladdict]

I have never heard of a manufacturer limiting the speed of the bike.  It is always the RPMs.


I do break in drills when I buy a new bike.

Let it warm up for a couple minutes.

1st gear 1/4 throttle until the recommended max RPM then close throttle and engine brake.  Repeat until I get board. 

shift to 2nd gear and repeat.

then shift through all the gears and engine break back to 1st gear.

I can get in 50 miles doing this in what seems like no time.  Then I let the bike cool down while I eat a meal. 

Sometimes I have changed the oil at this point.  Sometimes not.  Really depends on how it looks, etc.

Then I go for a ride where I vary the RPMs and use engine braking and start bedding in the front and rear brakes. 

Then I work the RPMs higher and higher.

The Royal Enfield Himalayan took about 1000 miles before it would happily rev to 5000 RPMs.  Now at 3000 miles it happily revs to redline during acceleration.  I have checked the valve clearances twice so far on this awesome bike. 

[chuck peterson]

I’ve never had a Trojan break...oh wait, conundrum, not ...

[Chuck in Indiana]

^^^^ channeling Huzo, eh? 

[Bisbee]

Ay caramba! Post something on this site  - never know what will come back at you.

[pressureangle]

99% of historical break-in had to do with flat-tappet camshafts and cylinder wall finish. Many engines now have roller cams, so the flat tappet break-in is less prevalent (still some have flat tappets, obviously) and each factory has it's method of cam break-in. Rings are a bit different; historically, cylinder wall finish was relatively coarse and often cast iron, and arranged so that the porous iron would be penetrated by oil and eventually wear smooth. So at the beginning, contact between the cylinder wall and piston rings was point loaded around the ring, wearing gradually to a smoother high-contact area across the ring face. So during break-in, too much speed would overheat the contact points and rings, coking the oil on the cylinder (glazing) or in the ring lands seizing the rings in the piston. Also since the seal was poor, too much cylinder pressure would blow combustion past the rings, overheating or melting them with the same or worse results. Thus the norm was light throttle and 1/2 max RPM for 500 miles or so.

Today, modern materials in cylinder walls and piston rings, and an enormously smoother surface finish allow the engine to be assembled with near perfect ring seal from the beginning, leaving only marginal break-in in the rest of the engine. So most engines today can get thrashed from brand new without hurting anything.
Flat tappet cams are still subject to the same considerations as always, though.

[Mike Harper]

What Patrick Hayes said is absolutely correct especially if there were visitors to the factory watching.

What a lot of folks did not see was the engine testing booths where they ran the engines on compressed air at unforgiving RPM for a time period that I didn't ever ask about but when they came out of that booth on their conveyor system the engines were smoking hot to the point I had doubts if I would buy one as a dealer. Turns out that a further break in was a moot subject.
However good early servicing by the dealers at set up time was important with the cylinder head re-torquing one of the most important. 

[Testarossa]

I know that break-in for modern Lycoming and Continental engines is normal warm-up and then full power for a couple of hours at least and 75% power cruise for the first 50 hours, to seat the rings as quickly as possible and prevent glazing. These cylinders are cast with their heads, so no head gaskets and no need to retorque -- Chuck may have a better handle on this. Here in Colorado this means the first flights are low-altitude blasts across the eastern plains out to Kansas and back to get the power needed.

My understanding and practice for Guzzi engines with modern nikasil cylinders is to run at varying speeds including some full-power time for three or four full heat cycles, then retorque, change oil, and repeat. Goal is to seat the rings without pushing pressure through the head gaskets. Again, at our elevations in Colorado a normally aspirated engine running wide open won't reach full gas pressure in the heads, but a couple of wide-open climbs up steep mountain passes should be in the mix. Will be happy to entertain other views.

[Craig in Alabama]

I've always thought one of the side benefits of the break-in procedure was that it allowed a rider to become familiar with their new machine at modest performance levels. Of course, any reasonable rider would do this, but there are a lot of folks who need a reason to take it easy at first.

Cheers!
Craig

[Tom]

https://www.youtube.com/watch?v=vTiYrTxH4X4

What Pat is talking about.  Cool short vid.