Running in....Please pass

[Bodysurfer]

Hello all.
I’ve just put the engine back in my @ after having the bores honed and new rings fitted. Although the bike is low mileage the last owner gave it much too easy a life and synthetic oil from the start. This resulted in glazed bores. I’ve run in a couple of new bikes in my time. While doing this I’ve never caned the living daylights out of them, but then again I’ve not been easy on them and it’s seemed to have worked. They all run fine and use no oil.
So a few questions……………does anybody know what sort of oil is put in a brand-spanking bike to assist the motor to bed in, as per most manufactures for the first 600 miles, or is this a myth.
I’m happy with my running in method but would be interested in any views………

[Mervinh]

use a good quality mineral oil i reckon, your running in method sounds good just dont let the engine labour let it rev freely but not over rev i always say
merv

[africa twin boy]

I have been reading about this for years, just never had the balls to do it.....
More info here. Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power

What's The Best Way To Break-In A New Engine ??
The Short Answer: Run it Hard !

Why ??
Nowadays, the piston ring seal is really what the break in process is all about. Contrary to popular belief, piston rings don't seal the combustion pressure by spring tension. Ring tension is necessary only to "scrape" the oil to prevent it from entering the combustion chamber.

If you think about it, the ring exerts maybe 5-10 lbs of spring tension against the cylinder wall ...
How can such a small amount of spring tension seal against thousands of
PSI (Pounds Per Square Inch) of combustion pressure ??
Of course it can't.

How Do Rings Seal Against Tremendous Combustion Pressure ??

From the actual gas pressure itself !! It passes over the top of the ring, and gets behind it to force it outward against the cylinder wall. The problem is that new rings are far from perfect and they must be worn in quite a bit in order to completely seal all the way around the bore. If the gas pressure is strong enough during the engine's first miles of operation (open that throttle !!!), then the entire ring will wear into
the cylinder surface, to seal the combustion pressure as well as possible.


The Problem With "Easy Break In" ...
The honed crosshatch pattern in the cylinder bore acts like a file to allow the rings to wear. The rings quickly wear down the "peaks" of this roughness, regardless of how hard the engine is run.

There's a very small window of opportunity to get the rings to seal really well ... the first 20 miles !!

If the rings aren't forced against the walls soon enough, they'll use up the roughness before they fully seat. Once that happens there is no solution but to re hone the cylinders, install new rings and start over again.

Fortunately, most new sportbike owners can't resist the urge to "open it up" once or twice,
which is why more engines don't have this problem !!

An additional factor that you may not have realized, is that the person at the dealership who set up your bike probably blasted your brand new bike pretty hard on the "test run". So, without realizing it, that adrenaline crazed set - up mechanic actually did you a huge favor !!

[StumpyFingers]

Originally Posted by africa twin boy

I have been reading about this for years, just never had the balls to do it.....
More info here. Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power

What's The Best Way To Break-In A New Engine ??
The Short Answer: Run it Hard !

Why ??
Nowadays, the piston ring seal is really what the break in process is all about. Contrary to popular belief, piston rings don't seal the combustion pressure by spring tension. Ring tension is necessary only to "scrape" the oil to prevent it from entering the combustion chamber.

If you think about it, the ring exerts maybe 5-10 lbs of spring tension against the cylinder wall ...
How can such a small amount of spring tension seal against thousands of
PSI (Pounds Per Square Inch) of combustion pressure ??
Of course it can't.

How Do Rings Seal Against Tremendous Combustion Pressure ??

From the actual gas pressure itself !! It passes over the top of the ring, and gets behind it to force it outward against the cylinder wall. The problem is that new rings are far from perfect and they must be worn in quite a bit in order to completely seal all the way around the bore. If the gas pressure is strong enough during the engine's first miles of operation (open that throttle !!!), then the entire ring will wear into
the cylinder surface, to seal the combustion pressure as well as possible.


The Problem With "Easy Break In" ...
The honed crosshatch pattern in the cylinder bore acts like a file to allow the rings to wear. The rings quickly wear down the "peaks" of this roughness, regardless of how hard the engine is run.

There's a very small window of opportunity to get the rings to seal really well ... the first 20 miles !!

If the rings aren't forced against the walls soon enough, they'll use up the roughness before they fully seat. Once that happens there is no solution but to re hone the cylinders, install new rings and start over again.

Fortunately, most new sportbike owners can't resist the urge to "open it up" once or twice,
which is why more engines don't have this problem !!

An additional factor that you may not have realized, is that the person at the dealership who set up your bike probably blasted your brand new bike pretty hard on the "test run". So, without realizing it, that adrenaline crazed set - up mechanic actually did you a huge favor !!

I have heard about this method but never tried it.
I used to run the engine up to temp then let the engine work without straining it. I used to run the first 600 miles in two days.

[jarl]

If I ever get a new engine I'll be being very gentle while she warms up, then a bit harder for 10 miles (i.e, normal riding), then purposefully riding very hard with lots of engine braking and a few runs to redline for the next 10, then change out the oil/filter and ride it normally for 1000, change oil/filter again (still mineral), then 4000 miles later change to synthetic. Obviously if it looked nasty then I'd change the oil earlier.

Don't wait to 600 miles to change the oil, and use a high quality mineral oil whilst she breaks in.

It seems one of the worst things you can do is be gentle during the break-in period. Since the only new parts are the rings/cylinder then you should be able to run it hard as soon as it's warm


p.s: I've talked to an engineer who designed engines before joining the uni, and whilst the break in period at low revs and low load was very important in the olden days, he says it's now unnecessary due to new manufacturing processes.

[thetimkirby]

I thought the main reason for running in was to allow the bearings to bed in. This is really only an issue for plain bearings, so if you've only had the bores honed, its not such a problem.

However, honed bores do let more oil by until they are bedded in, so if you cane it, it will probably let more combustion products into the crankcase.

Personally, I couldn't bring myself to thrash a new engine, especially if I've just put it back together myself. I've always run rebuilt engines in progressively, and you can feel them loosening up over the first couple of thousand miles. I'd need convincing that the 'thrash it in' method works.

[underbeing]

I'd be interested to know where you got it done and how much it set you back. My bores are in poor shape. It doesn't affect performance but uses a lot of oil. Did you have any work on the valves?

[Bodysurfer]

Originally Posted by underbeing

I'd be interested to know where you got it done and how much it set you back. My bores are in poor shape. It doesn't affect performance but uses a lot of oil. Did you have any work on the valves?

I removed the motor myself and took it to a bloke in Cardiff who comes highly recommended. He honed the bores fitted new rings and suggested new valve stem oil seals which were done. He charged £120 for the work and I supplied the parts which were about £170. I guess parts could be done cheaper with after market stuff but I chose to go with OE. Cardiff could be a long drag from your part of the world but I can supply details if you need them.

[AlanH]

Originally Posted by thetimkirby

I thought the main reason for running in was to allow the bearings to bed in. This is really only an issue for plain bearings, so if you've only had the bores honed, its not such a problem.

It's the other way around. Plain bearings require very little running in. Replacement rings and honed bores are more demanding. If you only have plain bearings replaced, much less running in is required - according to conventional running in techniques.

As for the article, I'd say it makes sense. My brother worked in a dealership years ago and most of the demo bikes were run in hard and quick with the oil changed well before the 500 mile interval. They were noticeably quicker than others that had been run in by the book.

[Kjell Lindberg]

Originally Posted by jarl

I've talked to an engineer who designed engines before joining the uni, and whilst the break in period at low revs and low load was very important in the olden days, he says it's now unnecessary due to new manufacturing processes.

That is what I have been told too.
The manufacturing tolerances are so much precise these days that the process of "running in" is of less importance nowadays.

I would choose an oil specification recomended by Honda for that model, since that is what the @ was designed to use.