Break In Break in oil ratio issue?

Discussion in '2-Stroke Engines' started by QuadManiac, Aug 17, 2008.

  1. QuadManiac

    QuadManiac Member

    1st post, newbie to motor-bikes, lotsa knowledge of small engines as in quads. I'm nearly finished installing a BGF 80 (69?) in my old Autobike Classic. Thanks to Pablo and Ghost0 among others, I'm also tortuously waiting till Tuesday to receive my Jackshaft kit, so I'll end up with a 6 speed automatic tranny. Installation is going well, so far.

    However, I'm a little concerned about the manufacturer's recommended break in procedure. Running with a higher than normal fuel/oil ratio during break in makes the fuel/air ratio somewhat leaner. (more oil means less burnable fuel volume, air volume is the same... so a/f mixture is leaner) Running leaner typically makes the engine run hotter and also promotes pre-ignition and it's resulting damage to piston, etc., neither of which I think is a good thing for an engine during its break in period. I am used to running a rich mixture during break in, especially on 2-strokes... but since i have no carb control over the mixture - only the fuel/oil ratio controls the air/fuel mixture (without re-jetting) - I am forced to run lean if I'm going to add extra oil during break in. Catch 22?

    I was wondering if anyone here has had similar concerns and perhaps solutions or whether I am just being my normal, over anal, engineer self?

    Glad to see this site is here!

    BTW, can anybody tell me who is the real manufacturer of the motors distributed by Boygofast?

    Last edited: Aug 17, 2008

  2. Bronzebird

    Bronzebird Member

    You seem to over think the air fuel ratio for "leaness"

    You can change the air with the 4 position circlip inside the carb barrel slide. However the expert hobbyman or author of black and white manual states 16:1 break-in mixture. And 20 or 25:1 there after the 200Km and no need to change the air mixture. I think more for higher altitude adjustment and I live at low altitude.
    I would not stress as mine has oil vapor condensed at the muffler. Which is the tail tell sign that my motor is getting lubricated well on the break in period.
    After 6 rides I saw the muffler screws that hold the baffle in were gone except for one screw with no nut. So I pulled the baffle out and drilled a few holes and now have a perky 2 stroke that wants to rev very nicely.
    I would like to hear how your break in goes. The headbolts need re-tourqing after each ride so far at 12.5 foot pounds on a 3/8" drive wrench. All so had to tighten frame mounts and fuel tank and carb bowl screws. I love it so far...
  3. Bronzebird

    Bronzebird Member

    7th ride with header gasket sealant needed.

    After the sixth ride I saw new spittles of oil on upper cooling fins. I retorq everything before each ride and realized the exhaust gaskets did not seal and not wanting to over torq bolt I added some high temp "ultra black" RTV. Also added 9/16th inch O-ring in carb manifold to carb clamp tube. More RTV added to tube compression slits for clampage. Oil vapor still condensing around bottom of frame and crank. More oil more better :smile: