running hot... overheating 2 stroke

Discussion in '2-Stroke Engines' started by woods39, Apr 15, 2007.

  1. woods39

    woods39 Guest

    MY engine is running hot. Does running your engine richer or leaner make it run cooler??

  2. jeffspeeder

    jeffspeeder Guest

    i may be wrong one of the other members probleys knows more about this then i do. but i dont think running it lean or rich will make a difference in how hot it runs cuz you should know if its running rich. as long as your not letting the motor stay on while not rideing it should not overheat.
  3. thatsdax

    thatsdax Guest


  4. retro_racer

    retro_racer Guest

    Thats right with about any 2 stroke/cycle motor.leaner will make it run hotter,and ritcher should make it run cooler.Easy principal to figure out.2 strokes use the oil in the gas to lubricate the lower end of the motor,as well as the cylinder walls,and rings
  5. Guest

    Guest Guest

    You are right when you say "you may be wrong here"...
    Running too lean will destroy your engine!

    Now woods, What makes you think it's running hot? Is it still new? How long have you run it?

  6. woods39

    woods39 Guest

    still breaking it in....

    I am still breaking in the engine...... When taking for a two minute cruise.... if I spit on the engine it sizzles like frying bacon.....
    Havent read optimize am about to....
  7. jeffspeeder

    jeffspeeder Guest

    well mine dose that to spitting on a motor will always sizzle if its on. im not shure what the running temp is on one im shure bikerjoe will probley tell you but if your motor is hot while your hand is more then 5 inches away i would be worried but as long as u jhave a good mix and your motor runs fine i would not worry about it
  8. JosephGarcia

    JosephGarcia Guest

    I run my engine pretty hard for hours at a time to travel between cities, its just "pretty warm" at the end of all that, I can put my hand on it for 15 secs or so before i feel pain. Or I just have a high tolerance for pain, lol.

    I've never spat on mine, but the advice in one of the previous pasts that says "if you can feel the heat from 5 inches away" makes sense, since my engine runs fine and I can only feel the heat from 1-2 inches away, nomatter the weather.
  9. Guest

    Guest Guest

    Well Jeff, I haven't checked the old "spit-o-meter" yet, but I know that a dirtbike engine sizzles when you run through water.....

    Keep an eye on it, and read the "Break-in secrets" and Optimize for your application.

    Check those gaskets!!!!!
  10. srdavo

    srdavo Active Member

    and......Stop spitting on your engines! :lol: :lol: :lol:
  11. woods39

    woods39 Guest

    No WAY

    No way Dude!!! Thats my RedNeck thermometer!! HAHAHA
  12. rcjunkie

    rcjunkie Guest

    Spit test isn't accurate. You should place your tongue against the cylinder head. If you can keep it there for 3 seconds before it burns your engine si running at correct temperature, if it burns instantly, too lean, if it takes longer than 3 seconds for it to burn, too rich.

    Its just that easy.

    The best way to tell if you are overheating is you are experiencing performance loss at full throttle. I ran my bike for 15 miles up a steep Colorado mountain last summer and my exhaust pipe was RED and engine head changed to a duller grey color. Did I overheat my engine? Apparently not, it never seized and kept chugging along without any loss of power or speed.
  13. Guest

    Guest Guest

    Yes, just that easy.

    Maybe you had a loose piston, or your muffler bearings were an exact match. :???:
  14. chances are you need a cooler plug(spark).. the cooler the plug the less local the fire hence allowing your engine to not race the temp up. Cooler plug richer carb setting (needle higher up) jet boaring (fuel mixture richening technique)? Check out a cooler plug first bud!
  15. Skyliner70cc

    Skyliner70cc Active Member

    Richer oil ratio means leaner air/fuel mixture and leaner means hotter.
  16. Bronzebird

    Bronzebird Member

    So fuel mixed at 16:1 is hotter cyclinder temps vs 20:1 runs cooler? Seems that more oil will burn the fuel slower and less heat :confused:
  17. Happy Valley

    Happy Valley Active Member

    "Richer oil ratio means leaner air/fuel mixture and leaner means hotter."
    "So fuel mixed at 16:1 is hotter cyclinder temps vs 20:1 runs cooler? Seems that more oil will burn the fuel slower and less heat"
    Huh? Which is it?
  18. Skyliner70cc

    Skyliner70cc Active Member

    There are 2 things to consider about mixture:

    1. Air to fuel ratio. Your carburetor ensures a proper mixture occurs so engine isn't run too rich (too much fuel for a given amount of air or not enough air for a given amount of fuel) or too lean (not enough fuel for a given amount of air or too much air for a given amount of fuel) HT carbs only allow for high speed mixture setting by adjusting needle height. There is no low speed or idle mixture screw to fine tune the carb.

    2. Oil to Fuel mixture: The more you displace fuel with oil, there is less fuel to burn for a given amount of air. Therefore, more oil (or richer oil to fuel ratio) causes an effective leaning of the mixture.

    Given the above, this is why I never run at 16:1 even when new. I usually run 32:1 when new and then lean it out to 50:1 using my secret oil that is obtained from pressing a bean...a bean that cannot be legally owned in the USA.
  19. rasndas

    rasndas New Member

    I have checked head temperatures on most of my air cooled engines with an infared thermometer and the run in the 260 to 290 degree F range so it is no suprise that the spit test wil sizzle. My motored bike engine is a 2 cycle engine that I bought from DAX. In my case the carburetor was set up excessively lean and I ended up drilling out the main jet several # drill sizes to get it to run correctley. After you make a run check your plug color to see if you are running too rich or lean. If it is white you are too lean.
  20. Skyliner70cc

    Skyliner70cc Active Member

    290 deg F is not too hot at all for a 2 stroke engine. I run my model engines at 310 max temp but only if I have a touch of castor in the fuel.