Break-in? should I stay under 15mph...

Discussion in 'General Questions' started by crowvise, Aug 3, 2010.

  1. crowvise

    crowvise Member

    Break-in? should I stay under 15mph...
    ...while going downhill if I'm not using throttle to obtain overage?
    ...or should I coast under 15mph using brakes downhill?
     

  2. RedBaronX

    RedBaronX Member

    I would say that as long as you are coasting in neutral, you can go any speed downhill during the break in...
     
  3. GearNut

    GearNut Active Member

    Assuming we are discussing a Chinese 2-stroke kit:
    Go as fast as you want to, just do not hold a fast or steady speed for longer than 100 yards or so. Vary your speed and throttle position for at least the first 2 tankfulls.
    It is best to run the engine hard in short bursts to let the piston rings break in properly.
    Never ever under any circumstances during the entire life of the engine coast down hill with the throttle closed or near to closed. The only lubrication that the engine gets is the oil mixed in with the gas. With high engine speeds and a closed throttle the engine will starve for lubrication. Hold in the clutch and let the engine idle while coasting down hills.
    Also with a new engine, first time out, ride it for 15 minutes or so then stop the engine and let it cool down completely.
    Second ride do the same for a half hour ride.
    Third time do the same as second ride.
    After that you should be good for long rides.
     
  4. crowvise

    crowvise Member

    I built a mount to aid in the break in process. Haven't used it yet. Are you saying I shouldn't tape the throttle at approximately 12-15mph for a half hour? how often would I need the 'burst'(ie. could I have it taped 5; 10; or 15 minutes then give it a 10 second burst? I don't like having to go slow on the road and not be able to quickly get out of sight in the event that an inquisitive war pig decides to draw a battle line.
     
  5. GearNut

    GearNut Active Member

    You can do smoky rolling burn outs if you want to, just don't hold them for longer than 3 seconds or so. The engine absolutely must be under a load, hauling your hiney down the road to properly break in. I never said go slow. Vary your speed from slow to fast to slow to medium to slow to fast..... you get the point.
    Just starting the engine in a stand with a fan or something blowing air on it is quite possibly the worst thing you can do to it.
     
    Last edited: Aug 5, 2010
  6. crowvise

    crowvise Member

    I'll take your word 4 it. You, and a small handful of others, helped me w/ my clutch problems in your responses to others w/similar problems.
    But for curiousity's snake: what is the science behind using/not using the stand idea?
     
  7. GearNut

    GearNut Active Member

    Do not forget the cool down rests, they are very important. Let it sit for at least 45 minutes. A total cool down of more than an hour is best.
     
  8. GearNut

    GearNut Active Member

    Piston rings are not manufactured perfectly round, and neither are cylinders.
    They must be properly broken in, or married, before you can expect the best sealing efficiency.
    In order for the piston rings to properly marry with the cylinder wall the engine needs to have a load on it.
    With the engine just running static in an engine stand at any speed there really is not much pressure applied to the piston. Yes you might get screaming RPM's out of it, but that is not really working the engine, just abusing it.

    When the engine is under a load you are putting resistance to the piston's ability to get pushed down by the pressure from the expanding gasses created by the combustion process. These gasses seek out every nook and cranny trying to escape. They will create pressure behind the piston rings, actually getting into the piston ring lands (ring grooves), forcing the piston ring outward away from the piston and pushing the piston ring's sealing surface tightly against the cylinder wall.
    When a cylinder is brand new or freshly rebuilt they are finish honed. This honing process not only precisely sizes the cylinder to the piston size, it also leaves a fine cross hatch of ridges in the cylinder finish. Quite similar the the face of a hand file. It is important that the piston ring gets worn down by this rough surface before the surface gets worn smooth.
    If this does not happen, the piston rings will never be able to properly seal against the combustion pressures and you will get what is called piston blow by. The pressurized gasses will blow by the rings and down the sides of the piston ultimately reducing the available pressure to push down on the piston and make power.

    There are many differing views on the whole procedure.
    This is the one that I mostly adhere to and It has not failed me yet.
    I did not learn the procedure from this site, but It best describes the whole gist of how and why.
    FWIW I do not agree with his take on heat cycling when it comes to these cheap Chinese engines (complete cool down between runs).
    http://www.mototuneusa.com/break_in_secrets.htm
     
  9. crowvise

    crowvise Member

    Thx man. You made my brain sigh. It craves details. (Like cold mountain water in a dry desert plain. -) My mechanic buddy takes offense if you ask any questions like that. Also for asking or bringing up someone elses opinion. Says angrily, that as long as he has been working on motorcycles, my doing so demeans his intelligence. Anyway, i also read the article last night. Going to subscribe. Would you say the other topics are as noteworthy/credible?
     
  10. RedBaronX

    RedBaronX Member

    it's too bad that your mechanic feels that way because I know for me, the more I understand about a portion of something-- like what GearNut explained about cylinder sizing and shaping-- the more I understand about the overall picture... the more I respect what's going on...

    I now know not just that "it is important to break in your engine" but what exactly is HAPPENING during the "break in"...

    As for the cool-down time, the written directions that came with my kit recommended a 20 minute cool-down between one's first few shorter rides. It doesn't say WHY you should though.
     
  11. GearNut

    GearNut Active Member

    As brand new parts get familiar to each other, certain areas will bear down harder than other areas and create hot spots. These hot spots can distort the wear surface and a distorted wear surface will not marry with another wear surface properly. Also the hot spots can get hot enough to exceed the material's operating heat range and dis-temper the material rendering it too soft or brittle to provide a long service life. The effect depends on the material at hand. Steel can become soft, aluminum can become brittle, ect. The action of properly heat cycling the individual internal components can also toughen them, leading to a longer lasting wear surface.

    I really want to leave references for you all to read, but I am just repeating what I learned at school and what I learned from my elders.
     
    Last edited: Aug 6, 2010
  12. Turtle Tedd

    Turtle Tedd Member

    HT Engine best break in procedures...read above posts by Gearnut two or three times...make sure you have a high ratio of oil in your premix , a little smoke wont hurt anything..you can go to 30 to 1 if you want after break in..get some extra plugs and change them out during break in often...nuff said
     
  13. RedBaronX

    RedBaronX Member

    GearNut-- you sound like you REALLY know what you are talking about, so I'm going to ask you about BEST oil:gas ratios for both break-in and post-break-in... Every owner's manual I've looked at gives different information, and it drives me nuts!

    The woman I bought the motor from said that running oil-rich all the time won't hurt anything... (extreme amounts would get expensive and very very smoky) but the two sets of instructions don't agree on ratios.

    So, I defer to you, GearNut... what do YOU recommend?
     
  14. GearNut

    GearNut Active Member

    Speaking for quality pre-mix oils ONLY:
    24:1 for break in.
    32:1 for the rest of the engine's life.

    Any oil bought from Walmart, Kmart, Fedmart, Lowes, Home Depot, ect. is JUNK!

    Use Maxima, Spectro, BelRay, Motul, and other quality oils made for motorcycles.

    Do not use weed wacker or leaf blower oil.
    The stresses and strains that an MB engine goes through are different than that of a yard tool. It does not matter if the engine was originally made for a yard tool, you are not using it as such, so do not treat it as such.

    Certain high end synthetic oils such as Opti2 are designed to run at 100:1.
    That is what the oil was designed to mix at, so follow ratio as instructed.
    Other synthetics run at 50:1 or 80:1. Read the bottle and follow the instructions for the oil you are using.

    Only as a last resort will I use a cheap brand (Poulan, ect.) oil to get me out of a bad "I have no oil, DARN IT!" situation if I am out on the road somewhere and out of gas.
    I try to plan ahead, but nobody is perfect.
     
  15. Lazieboy

    Lazieboy Member

    Give her the Gusto

    As soon as i got mine going I took her for all she was worth. I must not of read that chapter. Engine still runs awsomly.
     
  16. RedBaronX

    RedBaronX Member

    I picked up "2-stroke outboard motor oil" from the hardware store... I figured outboard motors are run basically as rough as a MB, but if you think it would not be good enough, I'll either save it for an emergency day or take it back.... would I find higher quality at an auto parts store? At this moment, I have no transportation except for the bus, so my shopping choices are limited.
     
  17. GearNut

    GearNut Active Member

    Oh HECK NO!
    Do not use outboard marine oil!!!!!!
    That is designed for a water cooled boat engine. They have very different requirements than an air cooled engine.
    Consider that the cooling water of a boat engine is at the temperature of the lake that you are floating in, therefore it runs alot cooler.
    An air cooled engine runs much hotter than that.
    Even a modern water cooled dirt bike engine runs hotter than that. That is why oils for modern motorcycles are still compatible with air cooled motors.
    Marine oil will greatly reduce the life of your engine!
     
    Last edited: Aug 10, 2010
  18. GearNut

    GearNut Active Member

    There are no motorcycle stores near your place?
    Honda, Yamaha, Kawasaki, Suzuki "factory" oils are better than the cheap stuff.

    Do you live in an agricultural area? I know that years ago Farm and Fleet used to sell Honda dirt bike oil. How about Tractor Supply? I never go there much, it is on line only for me.
     
  19. RedBaronX

    RedBaronX Member

    then I am REALLY glad I asked (and really glad that I didn't finish my bike on Sunday...) I wasn't thinking about air- versus water-, I was just thinking about the weight of workload... I picked this stuff up because I was at the hardware store anyway picking up some more paint, hardware for mounting my bigger tank... and this was all they had besides weed-whacker oil. If the label had specified air- versus water- I would have known better

    as for finding a motorcycle shop-- it's a matter of finding one that I can actually get to on the bus (and then finding one that isn't all Harley, Harley, HARLEY!).
     
  20. crowvise

    crowvise Member

    hey gear nut,
    what's the ratio for motul? Break-in and after? One shop I went to carried only motul. $17.00 a qt. Is that price the average for it? Is it average for the other quality MC oils?
    Oh, and with that break-in info you gave me, after that third 1/2 hour run how long is a long run?
     
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