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Dodogree

Engine run in and pillion

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fred_jb
1 hour ago, embee said:

Not that anyone is interested, but just for you Steve ...... ;)

 

Not true - I'm always interested in this sort of stuff. :D

Edited by fred_jb
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Dodogree

Wow, what a wealth of information.

Thank you all for your advice.

Oh, the Mrs also thanks you!

 

Could someone please explain why the S mode is preferable to the D mode for running in?

I'm using it already, but I am very curious to understand why.

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slowboy

Thanks Embee, nice to read the reality of it from someone who really knows. Like Fred, I'm also interested by it.

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Trumpet
On 15/01/2018 at 22:36, Dodogree said:

Wow, what a wealth of information.

Thank you all for your advice.

Oh, the Mrs also thanks you!

 

Could someone please explain why the S mode is preferable to the D mode for running in?

I'm using it already, but I am very curious to understand why.

Being too gentle is bad. Being too rough is not so bad these days. The S mode excercises the motor better.

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Finlayson99
On 14 January 2018 at 21:09, SteveThackery said:

 

I'd like to understand this better, because in the motorsport industry "running in" is extremely brief compared with the norms for road vehicles.

 

What is different?

 

Because engines in Motorsport are used for a relatively short period of time an generally not run for thousands of miles over many years so longevity isn't the primary concern??

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SteveThackery
11 hours ago, Finlayson99 said:

 

Because engines in Motorsport are used for a relatively short period of time an generally not run for thousands of miles over many years so longevity isn't the primary concern??

 

Yeah, could be.

 

Someone told me that the only thing in a modern engine that actually gets "run in" is the rings to the bore.  I wonder if that's true.

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GerJ
On ‎15‎-‎1‎-‎2018 at 23:36, Dodogree said:

Could someone please explain why the S mode is preferable to the D mode for running in?

I'm using it already, but I am very curious to understand why.

You do not want to lug the engine, especially when running in, especially 2-up. In S-mode the gear box shifts at higher revs, and that is easier on the (new) engine.

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embee
5 hours ago, SteveThackery said:

Someone told me that the only thing in a modern engine that actually gets "run in" is the rings to the bore.  I wonder if that's true.

In essence, yes. As Andy said earlier, it does also benefit the transmission gear teeth, but all the other stuff (bearings etc) generally works on hydrodynamic oil films so no actual contact worth mentioning. Traditional sliding contact cams and followers also work on boundary lubrication at low speeds (though NC roller followers eliminate this aspect) but the loads are known and lubrication regimes improve with increasing engine speed so they don't benefit from low speeds.

 

I don't actually agree with the "avoid lugging" philosophy as such. It's fine to use high loads and low speeds during the break-in, as previous discussions have covered, the engine is fine under these conditions, it's just a question of how comfortable you are with the refinement (or lack of). The most important aspect is to progressively increase the speeds and loads you use throughout the process, avoid regular use of high engine speeds in the first few hours.

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Foxy

Just read the Bradley Smith interview in February Bike mag, he talk about tolerances on F1 engines now being so tight that they have to warm the oil and water before they fire the thing up. As previously stated race engine are not built to last like road vehicles, but if things are that tight you would think there would be some kind of "running in" procedure. Any F1 engineers out there?

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embee

It's nothing new for F1 engines to require heating before running. Road engines are made to operate anywhere from -40C to +50C ambients, including starting from cold. Clearances have to allow for differential expansion rates, pistons heat much more rapidly than cylinder blocks. There's no reason why you have to allow for this sort of thing in an F1 engine when you can design it to be at its optimum while in use, and heating before running it is a minor inconvenience. F1 tyres aren't used from cold.

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