Can someone please explain engine break in period?

[Skyboy8950]

Hey,

So just rebuilt the engine (down to the base gasket). Got new gaskets and rings, no valve job though. Now I know I need to break this thing in, but I don't know the standard protocol. I have put about 50 miles on it and have been very gentle with her. I haven't taken the RPMs over 4500 or 5000, easy acceleration, nothing fancy. Is this right? How long should I baby her? Is there something I'm missing?

[tkent02]

. I have put about 50 miles on it and have been very gentle with her.

Too late, you have already wasted the window of opportunity.
Read this anyway:

http://www.mototuneusa.com/break_in_secrets.htm

Read it all.

The easy break in thing is just lawyer speak to prevent people who don't know how to ride from going too fast on a bike they don't yet know. Even so, there are a lot of crashes in the first few miles, so I can't blame them.

[Dave8338]

Too late, you have already wasted the window of opportunity.
Read this anyway:

http://www.mototuneusa.com/break_in_secrets.htm

Read it all.

The easy break in thing is just lawyer speak to prevent people who don't know how to ride from going too fast on a bike they don't yet know. Even so, there are a lot of crashes in the first few miles, so I can't blame them.

Ride it like you stole it in 2nd gear!

Several schools of thought here. If you hammer on a little and then let things cool down through some mellow riding and repeat... you'll be good to go.

I've watched small block Chevs break in at 3000+ RPMs on the dyno for 2-3 hours...

[Theo]

Too late, you have already wasted the window of opportunity.
Read this anyway:

http://www.mototuneusa.com/break_in_secrets.htm

Read it all.

If I had a rebuilt engine, that's the way I would do it. Ride it like you stole it.

[Steve]

I agree, it's too late.

You need to apply pressure to both sides of the rings, with acelleration and decelleration.
Do this for a few heat cycles and you are good to go well within your 50 miles that you have already wasted.

.

[Nessism]

I tend to disagree. How can it be too late? If the hone is worn it will be worn by what? The ring of course. And when the rings wear they will bed in like expected.

My break in technique is to ride the bike in the city for a while, using the throttle liberally like would normally be the case. Don't lug the engine and use the throttle. After 100 miles or so start using the throttle more liberally. I did some roll-on on the freeway, speeding up and slowing down, again and again. After a few more miles I did some 3rd gear roll-ons, on the freeway, letting the engine pull up to high rpm. Do that a few times and call it done. Honestly, I don't think you can do it wrong other than maybe lugging the engine too much or not using enough throttle. Just ride the bike normal and you should be fine.

[chef1366]

The first start up I set the idle at 4-5K and let it go for ten minutes or more.
Then a ride it like any other bike I ride. Hard.

[49er]

The first start up I set the idle at 4-5K and let it go for ten minutes or more.
Then a ride it like any other bike I ride. Hard.

HARD!! How many have ya stolen Bill?

Seriously, the Mototune method is the way to go. The draw back though is that you need to have your tuning parameters pretty accurate from it's first fire up to take advantage of the initial ring seating "window of opportunity". Don't leave the bike idling too long for warm up. A higher flat rpm warm up isn't as beneficial as a shorter warm up followed immediately by a hard acel/decel period over the first 1/2 hour of running.

I used this method to run in my 850 and it's performed admirably ever since.

[Skyboy8950]

Well, I guess I f*cked that one up. Guess I'll have a crappy running bike from now on.

[Turtleface]

Well, I guess I f*cked that one up. Guess I'll have a crappy running bike from now on.

Compression check?

[Nessism]

Well, I guess I f*cked that one up. Guess I'll have a crappy running bike from now on.

Nonsense! Your engine will be fine.

The easy break-in recommendation is industry standard (as far as I know) within the Japanese motorcycle industry. My guess is that 99% of the engines broken in this way have been fine going back to our GS era. The recommendation may have something to do with reducing liability as Tom states, but I seriously doubt there is concern with ruining the engine along the way.

All this said, I recommend taking your bike out and running it hard for a while. Can’t hurt plus it’s fun too.

[Skyboy8950]

Well, here's the real deal.

I didn't hone the cyl walls. I merely swapped out rings. According to that guide, the hone helps shave the rings down. Well, there is no hone to do that. I guess I did this thing half-assed. But it still pulls and rides well, so whatever. Hell, I didn't know. Live and learn.

And this morning, I did open it up a bit. Runs hard.

Must change oil soon though. I'm sure there is a bunch of crap in there.

[49er]

Well, here's the real deal.

I didn't hone the cyl walls. I merely swapped out rings. According to that guide, the hone helps shave the rings down. Well, there is no hone to do that. I guess I did this thing half-assed. But it still pulls and rides well, so whatever. Hell, I didn't know. Live and learn.

And this morning, I did open it up a bit. Runs hard.

Must change oil soon though. I'm sure there is a bunch of crap in there.

As Ed has said, you haven't done any harm.

The big problem though is you have different shaped bores and rings now in each cylinder. The honing process allows new rings to lap onto the shape of the bores by wearing fine particles of metal off their surfaces. This process happens fairly quickly, hence the need to work new rings hard during the first 50 kms (30 miles) of running. It's not the end of the world if you can't achieve this, but your engine will never reach it's full potential as far as torque is concerned.

An engine is never fully run in until at least 5000 miles and sometimes a lot longer, but the breaking in after that first 30 miles is a lot more gradual.

If you don't work the engine hard up and down on accel/decel in the lower gears early enough, the engine takes a lot longer to bed down and never reaches the sealing pressures that it could have. This equated to less torque and HP.

Have a good read of the Motortuneusa article above.

Your new rings won't fully bed in without a honing of the bores. Probably worthwhile pulling it down again and doing a hone. Then you can enjoy running it in as suggested.

[tkent02]

Have a good read of the Motortuneusa article above.

Your new rings won't fully bed in without a honing of the bores. Probably worthwhile pulling it down again and doing a hone. Then you can enjoy running it in as suggested.

Might as well wait a little while to see how it works out.
I am not real optimistic about getting a really good seal without having been honed, but it may work good enough. He didn't really mention his plans for the bike, racer, commuter, fix and flip, perhaps restore it to perfection and keep it forever? For instance, for commuter use I wouldn't really worry about it unless it runs poorly or smokes going down the road.

Give it a compression check now and again in a month, track oil consumption, see how it runs.

At least ride it until a convenient time to tear it down again, like October maybe.

[Footy.]

Do not use synthetic oil during this period, particularly since the bores were not honed. Use a 15-40 diesel oil for at least 2-3 thousand miles.

Footy.