Cold start in winter 2-stroke

Discussion in 'Motorized Bicycle General Discussion' started by BlueSmoker, Oct 15, 2016.

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  1. BlueSmoker

    BlueSmoker New Member

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    How is it to cold start those 66cc 2 stroke engines in between -0 and -20 celsius (35F to -4F)?
    Do i need to have the bicycle inside at winter? Do cold start harm the piston and cylinder badly? Do the piston easily freeze and stuck? Is it hard to coldstart?
     
  2. Springfieldscooter

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    If the carb is properly tuned, you will have no issues at all.
    You may/may not even need to choke it.
    I think its beneficial to let it idle for 30 seconds or so to warm up, but on my daily driver, I just start up and go!
     
  3. Slogger

    Slogger Member

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    At 4 below zero I hope to never find out.
    BRRRRRRRRR!
     
  4. crassius

    crassius Well-Known Member

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    engine should work OK with a bit of slow warm up - you probably won't enjoy the ride tho

    in the early 60s I sometimes had to ride a motorcycle to work on 0F to 20F days - hurts a lot and with snow on ground one falls down a lot - cover your ears well, as that's where I took some frostbite
     
  5. sbest

    sbest Member

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    I have 40 years of snowmobile experience mainly with piston port type 2 strokes. Always kept the sleds outdoors. They will start and run even at -30, but of course, will start better if kept indoors. The oil tends to thicken up on the cylinder walls making initial start hard unless you are using a snowmobile type synthetic injector oil, which is formulated against this. Sled oils are your best choice for near freezing temps.

    Forged piston (we have cast) are at large risk in cold temps. Cast not so much but always allow a warm up in any temp. Idling, especially with choke on, tends to foul the plug, so start up and start away on light load, taking choke off when you can.

    Yup, coldstarting can be hard. Strong spark, good compression and right gas mix is essential.

    Jetting NEEDS to be adjusted for temperature. Jetting that is spot on at 20c will destroy pistons at 0c. Need to richen up considerable for cold temps. Hard to believe that -20c will burn up pistons but it will. Every 10c requires a different jet setting.

    This is from last winter:
    [​IMG]

    I run sheet metal screws in the knobs of my MX tires on my KTM in the winter for traction on ice.
    [​IMG]

    [​IMG]
    Hand guards, "lobster" gloves and full face visored helmet help. As do knee and elbow pads for the inevitable falls on ice. Hips take a beating too.
     
  6. Kioshk

    Kioshk Active Member

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    What SprinfieldScooter sez: make sure your carb's tuned and you won't have problems, I find that the choke can come in handy on particulary cold days too. The coldest I've run on regular cruisings is 15-degree F. Let the engine warm up for about 30-secs before loading it up.
     
  7. Allen_Wrench

    Allen_Wrench Resident Mad Scientist

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    Been there, done that. As they said, tune it and it'll do fine. Last winter I think mine took maybe 10 or 20 seconds longer to get nice and warmed up. After that, she ran like always.
     

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