Breaking in new motors

Discussion in 'OT Driven' started by psyclone, Apr 5, 2010.

  1. psyclone

    psyclone o_O

    Joined:
    Mar 8, 2009
    Messages:
    114
    Likes Received:
    0
    Location:
    Australia
    How important is it to keep under the break in revs? Is close enough good enough?

    I am supposed to keep the motor in my new Ninja 250R under 4000rpm. But to go 50mile and hour in top gear, the revs sit on 6500rpm. Its a bike designed to rev high, redlines at 1300rpm.

    I have just finished my first 500miles (in 3 days) and most of that was up around 6500rpm. I couldnt really help it - just kept revs down as much as I could
     
  2. 7960

    7960 New Member

    Joined:
    Oct 17, 2004
    Messages:
    60,415
    Likes Received:
    0
    Location:
    New England
    you're going to read a lot of "I heard"s in this thread, and most of it will be crap.


    having said that, I heard it wasn't so much what the RPM is, as much as it's how long you sit at one RPM. so it'd be better to bounce between 6k and 7k RPM than it would be to sit at 6,500 RPM for an extended time.
     
  3. AVengeance

    AVengeance Active Member

    Joined:
    Aug 17, 2004
    Messages:
    22,615
    Likes Received:
    0
    Location:
    In my bunker Position:Hunkering
    What 7960 said is correct. Vary the revs and keep the speed down, and don't pound the crap out of the bike until after its first oil change.

    I bought a brand new 250R last year, and, like you, couldn't help but rev it to 6500, just to not get run over on the highway. I just took it easy, let people pass, and tried to speed up and slow down a little to help the valvetrain wear in properly. I have about 5000 miles on the bike now, and it's running great.

    If you do a lot of highway riding, I'd suggest stepping up a gear tooth on the front sprocket, or going down a couple on the rear. You'll drop your highway RPMs a little and move up your 6th gear shift point. You might even stop trying to shift into 7th gear (it's something I still do, after 4000+ miles), and will be looking into sprockets shortly.
     
  4. psyclone

    psyclone o_O

    Joined:
    Mar 8, 2009
    Messages:
    114
    Likes Received:
    0
    Location:
    Australia
    thanks guys :) I did vary the revs a fair bit- most of those roads were really steep and windy - the gear box got heap of use too. Will get the first service done asap. Its due in the next 100mile, and that wont take long to click over.

    The gears annoy me a bit. Its tempting to go up two gears at a time when you take off. I spend all my time in 5th or 6th gear then frantically tap down to first when I come to a stop at an intersection. When you push up towards 6000rpm to change up you are nearly at the same revs on the next gear. I know its a 250 - its just a bit annoying.
     
  5. GammaRadiation

    GammaRadiation Active Member

    Joined:
    Feb 15, 2007
    Messages:
    29,840
    Likes Received:
    0
    Location:
    Random Location.FL
    Brake in is always about keeping the load low and varying the revs a lot. They give guidelines like "keep it below x RPM" for people that dont understand its purpose.
     
  6. Pepe

    Pepe New Member

    Joined:
    Apr 11, 2009
    Messages:
    1,721
    Likes Received:
    0
    Location:
    8 Mile
    ride it like you stole it
     
  7. psyclone

    psyclone o_O

    Joined:
    Mar 8, 2009
    Messages:
    114
    Likes Received:
    0
    Location:
    Australia
    So when you say keeping the load low you mean don't labor it? Keep it above 3000rpm for hills?

    I am hanging out to take it out wind the revs out to 11,000rpm - uptowards thje top of the power curve. I guess after the first service where they change the oil and I should be able to start pushing it?
     
  8. GammaRadiation

    GammaRadiation Active Member

    Joined:
    Feb 15, 2007
    Messages:
    29,840
    Likes Received:
    0
    Location:
    Random Location.FL
    Load being how much work you're asking the motor to actually do. You can be at 10,000 RPM but not accelerating therefore the load is low.

    What most people dont know is the first thing done to an engine once it is built is usually brought near 80% readline for a few seconds right off the bat. This is LOOONG before you ever start your break in process. More or less your break in process isn't to seat the rings or working in tolerances (this happens fairly quickly), but rather to clean out the ground metal that is inherently going to arise from the initial break in, and you dont want to put a big load on the engine when you're running metal shavings in your oil.
     

Share This Page