1. 4 Stroke Husqvarna Motorcycles Made In Italy - About 1989 to 2014
    TE = 4st Enduro & TC = 4st Cross

TE run in period?

Discussion in '4 Stroke' started by sidquick, Sep 27, 2009.

  1. Slowpoke Husqvarna
    AA Class

    Location:
    Southern Ontario
    What's to fix?

    Seriously......

    I'm always willing to be shown wrong and would genuinely like to see how the slow method is actually superior. I hear lots of guys talk about it, but nobody seems to lay out the actual evidence of how and why. Laying out the evidence might finally deflate this long time argument....?

    Been playing with engines for a long time and also since 2006 I've followed lot's of forums such as this one and have yet to see an engine failure positively directly due to 'fast' break-in. Have seen lot's of engine failures from a multitude of other reasons..... Have seen lots of reasonable evidence pointing to long term problems with slow breakin.....

    Just sayin..
  2. union7 Husqvarna
    C Class

    Location:
    colorado
    Many tuners and manufacturers of crate engines recommend a procedure thatalso happens to be "short/quick" with these guidelines:

    1) Do Load the engine in increasing steps.
    2) DO Raise the engine speed limit in steps.
    3) DO NOT maintain break in load for an extended time, do it in short bursts.

    The basic idea is to load things enough to fully seat the surface (ring to cylinder wall etc) and let them "lap" each other. But only do it in a short burst so that no localized hot spots occur. Try to imagine that at a very detailed level you may have some relative high spots (very minor with todays machining capabilities). So upon first run-in the break in is trying to lap these rough spots, but you don't want to heat that spot. Lap,let that spot cool down and lap again. So you only have to load the engine then unload it for a few seconds then do it again, each progressive time the lapping will be less as it is improving every time.It's the same idea as sanding a heat sensitive part on a belt sander ,don't stay in one spot ,but frequently cool it down. Again one does not want to cool the entire engine down (lol!) just unload the worked on area briefly so it's localized heat can dissapate to the rest of the metal mass.

    Procedure something like this:

    using a low rpm ceiling (~1/3 of redline rpm )
    make a pull at 1/4 throttle from low to 1/3 of redline
    (boggging an engine is always bad so don't)
    coast in gear (want to load both sides) back down
    repeat 4 more times

    repeat entire sequence above for 1/2, then 3/4 then full throttle

    raise rpm limit to 1/2 redline rpm,3/4, full with same load increase steps.

    none of this is carved in stone it is just the basic idea that you do want to load the engine , but you do not want hot spots. And of course you want to load/rpm gradually.

    important adjust your start rpm and gear so that the engine load is not maintained for more than a 5 second pull, this is so you don't create hot spots.

    after it's all done change the oil, also it is usually done with non synthetic non energy conserving oils. (no moly).