Starting in Cold Weather

Discussion in '2-Stroke Engines' started by quadanar, Dec 15, 2006.

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Can you start your motorized bike in cold weather?

  1. Yes

  2. No

    0 vote(s)
  1. quadanar

    quadanar Guest

    Hi, I'm a rider from Tucson and I'm having some trouble starting a 48cc 2-stroke in cold weather (this is my first winter with a bike), which is ironic considering that the average temp here is about 65F in December.

    So, basically my bike rides/starts fine during the day, but after sunset when the temp is below 60F I can't start my bike. Playing with the clutch, choke, and throttle does nothing. It will start for a moment but then cuts out. Even force pedaling the engine to turn over and warm up (so the manifold is warm to the touch and my legs are pounding) doesn't help, it just putters like the thing is out of gas (and it has a full tank).

    I surmise that it might be my gas is too cold. The bike will run for about 10 seconds at first (the gas already in the carb) but after new gas funnels in the engine stops. What I'm wondering is if anyone else has had trouble starting a motr'd-bike cold in relatively cold weather. Should I look to get insulation on my gas line? Is there something like anti-freeze for 2-strokes that I should use? Or do I just have to take a blow dryer to my gas line to start the thing up?

    I know its not a problem with the gas mixture since I'm able to ride the bike for 4+ miles during the day and it runs normally (besides my rattling fenders), but coming home at night (just after sunset) the engine just won't start. Any thoughts?

  2. Steve

    Steve Guest

    Sounds like it's the dark of night that it does not like, not the temperature! :lol:

    Just kidding...the temperatures you are talking about will have nothing to do with fuel flow, so don't worry about that. The only thing that really has anything to do with it is mixture. I know you don't want to hear it...probably don't want to deal with it, but I'd richen the mixture at least one notch on the needle, maybe two, and see what happens.
  3. srdavo

    srdavo Active Member

    Nov 4, 2006
    Likes Received:
    Hi, I've ridden in a lot of cold weather (below freezing) and never had a problem. I start out with full choke, lever up, then when it starts I gradually move the lever down. Usually 1/2 choke for 2-4 blocks then lever down and ride normal.
    Maybe it's not the cold......your bike might be afraid of the dark? haha
    just kidding.....I'm sure some of the guys here will have some insight on your problem. good luck
  4. quadanar

    quadanar Guest

    By richen the mixture do you mean put in more oil? I usually use about a 30:1 ratio and the tank currently has fully-synthetic 2-stroke. Would putting in a more concentrated ratio help the engine run smoother?

    So, After extensive testing (down my street and back ...) I've concluded that the engine is prone to failure just as much in the heat of the day as at night - yea, it cut out again. So this time I drained the tank and replaced the gas and it runs fine.

    I didn't ride the bike for about 3 weeks and the gas sat in the tank the whole time, maybe that was the problem ... I guess I'll just have to make sure to ride the bike every day. Now to see if I can ride it at night ...
  5. Steve

    Steve Guest

    No, by richening the mixture, we mean richen the carb (fuel to air ratio), but it sounds like you've found the problem. Teoretically, the engine needs a richer fuel to air ratio when it's cold, or when the air is colder because the air is denser (higher oxigen content) when it is colder.

    It is good practice to store your fuel in a sealed container mixed, and only put the amount of fuel in the tank you think you will use in a short period of time. By doing that, the fuel stays fresh longer. The trick is to estimate the amount you need accurately, and not run out. :lol:
  6. bamabikeguy

    bamabikeguy Active Member

    Sep 30, 2006
    Likes Received:
    One of my GEBE engines hadn't been cranked in a long time, and a sure fire way to get it to start on an icy day was to take off the black cover, and pour a smidgeon of gas right into the screen.

    Two pulls and "vrooooom". :eek:


    Make that "vreeeeem". :wink:

  7. bird

    bird Guest

    what part of town are u from.
    sometimes i have the same trouble i just put the choke all the way up then prime the carb a little then ride till it fires then while riding slowly put it back down till the motor runs smoothly.
  8. Tom

    Tom Active Member

    Aug 4, 2006
    Likes Received:
    I dont even need to hit the choke.

    If I drop the clutch, i skid a little usually, but to overcome that, i just keep pedaling as i drop the clutch
  9. gone_fishin

    gone_fishin Guest

    welcome to the forum, quadanar :)

    my bike stays inside, but i still have to choke it to get it fired-up...about 30-45 seconds of that & i'm off and running 8)
  10. bamabikeguy

    bamabikeguy Active Member

    Sep 30, 2006
    Likes Received:
    Mr. Quad,

    Your second post holds part of the answer. The better a person breaks in the engine, after a certain point the engine is going to "kick in" or "surge", on these 25 cc engines at about 150 or so miles.

    More use makes easier operation, AS LONG AS THERE IS OIL IN THE GAS.

    The mixture you end up with will affect "carbon buildup" at a certain point.

    But at around 1,000 miles or so, these 25 cc. have "seated into the cylinder", and optimum performance commences.

    SUPPOSEDLY, there is a simple grinded screwdriver tool that could be carried along in a tool kit for scraping out that carbon, BUT I HAVEN'T SEEN A PICTURE OF ONE......hint hint..... :wink:

    BTW: did anybody hear "CarTalk" on NPR yesterday, where they were talking about 2 cylinder engines running the earliest airplanes after Kitty Hawk?

    They used Castor Oil, and the reason they wore long long white scarves was to "filter the fumes that blew in their faces", causing bowel emergencies for the "scarfless" pilots. :p
  11. Connor

    Connor Guest


    Bummer for those without a scarf.

    Interesting facts
  12. I know this probably sounds inconsiderate towards our lovely planet and everything but I'm using the synthetic oil now and it's great and everything but I miss the smell of the natural smoky blend!

    I may switch back just for the scent...
  13. gone_fishin

    gone_fishin Guest

    yup, nothing but good ole briggs & stratton "ready-mix" for my baby 8)
  14. quadanar

    quadanar Guest

    1 Month Review

    So, it's been a month and I've ridden my bike at least twice a week since then to keep the gas flowing.

    It turns out the solution to my problem was the choke. See, I'm used to the old lawnmower chokes where it's all the way up to start then thrown all the way down to run. After trying my bike out a couple of times though I've figured out the easiest way to get it started is choke up then push it down a quarter of the way every few seconds into riding until I feel the full power of the engine and get the choke down all the way.

    Now whenever I first start riding its with my right hand on the throttle and my left fiddling with the choke until the engine's power kicks in - oddly just a few millimeters of movement and I can feel the difference.


    Thanks for the welcome everyone! I'm from the east part of Tucson (Pantano/Golf Links area if you know it), though fairly soon I'm going to be riding across town to Pima West Campus when I'm out of a car (straight through that downtown cop zone I've been avoiding ... there are six drivers and four cars at my house and I usually have the last say in a car, it's why I bought my MoBike in the first place). Anyone from Tucson have suggestions on which road to take? I'm thinking Broadway since it has a full bus lane that bikes can use (plenty of space to avoid cars), but then 5th and Pima are more residential zones with reduced speed limits, but 5th is known to have a lot of motorcycle cops and Pima is a little north of where I need to be. Check out the bike maps and MoBike rules for Tucson here, if you interested.

    Anyway, I know I've broken the engine in well enough, I kept the riding under 25 for the first 200 miles (my little digital odometer says something like 325mi now ... I've probably totalled over 700 in all) and now my 48cc tops out at 35mph with decent acceleration.

    Now I've switched over to this blue-colored 2-stroke motoroil (from the red colored full-synthetic I was using) in the past week or so. Is there a big difference in the oil you use? The people that sold me the bike told me to use only full-synthetic, but the mechanic and 3 or 4 Autozone guys I've talked to about the engine have said to use normal motoroil now and only synthetic after the engines been worn out. Does real motoroil hurt the smaller 2-stroke engines? I've never heard a definitive answer on what's the best oil and mix for a 48cc Skyhawk engine.
  15. gone_fishin

    gone_fishin Guest

    well, it looks like someone's been havin' a good time :)

    i do the same thing as you, but i "set" the throttle & reach down with my r-hand to tweak the choke, idling along for about 45 seconds til the choke's wide i go (it still needs a bit of warming up tho)

    this gearhead's opinion is "if i use briggs & stratton easy-mix real oil, i can still wear my usa-flag-pin on my coat"...does that make any sense?
  16. psuggmog

    psuggmog Guest

    I have rebuilt numerous 2stroke chainsaw engines, most of which were used to either by loggers or chainsawcarvers. These engines were used hard, continously for long hours day after day. Most of the engines failed for one of two reasons, either overrevved or run with gas more than one month old since mixed with oil. They all failed in the same way. The piston siezed, all the damage was on the exhaust port side of the cylinder and piston. Most of the chainsaw venders are selling synthetic oil nowdays. The British Seagull marine engine website recommends continuing to use petroleum based oil in their engines. They also say that once you mix oil with the gas it severly decreases the gas storage life. My advice to use the twostroke oil of your choice, but don't use stale fuel older than one month since mixing. The oil in the fuel lubes all the bearings and decreases cylinder wear.
  17. sherryc8641

    sherryc8641 Guest

    I Can ride in the cold.

    My 70cc engine has no problem starting up in the cold. It is brand new though, if that has any effect. It can start when I even see ice on the ground! :cool:
  18. Guest

    Guest Guest

    1000 miles for break in on this engine? Sorry, but that is in no way accurate. I have a new engine that I will measure break in with a compression guage. I'll measure compression after every 2 hours of use and let you know when maximum compression occurs. Max compression is indication that rings are properly seated.

    With that being said, my 1.9L diesel engine in my vehicle hasn't reached its full compression yet at 22k miles. My last diesel took 50,000 miles to reach maximum cylinder pressure (525 psi on an engine that has about a 20:1 compression ratio). I like to brag about my VW TDI Diesel...I love getting better fuel economy than most motorcycles (45 in winter 50mpg in summer due to differences in BTU content between summer and winter diesel and cold weather starts/longer warmups in winter)
  19. quadanar

    quadanar Guest

    The manufacturer said the breakin period was the first 2 tanks of gas, and not to rev the engine too high until after that. I'm not sure how long it would take to reach the engine's full potential though, I'm not that familiar with 2-stroke's. I'm guessing they mean for the engine to be fully lubbed up before really using it.

    Thanks for the advice on the gas, I'll make sure not to mix the gas until I'm about to use it then (... thoughts of a flying off my bike while when my engine rips itself apart does NOT sound fun).

    Just curious, what are the chances of a piston seizing like that? Last week I ran out of gas on the way to work and stopped by the quickmart to get a little gas and some oil, I only had time to pour in some oil with the gas and shake my bike around a bit and didn't get a chance to properly mix it until I got to work a few miles later. What are the chances of badly mixed gas like this blowing a hole in your engine?
  20. etheric

    etheric Guest

    Quadanar, I'm sure you went to the oil-heavy side of your estimation, in which case you may not notice any problems on a short run, but may foul your plugs sooner than later if you do it alot. You may seize if you are running with very little oil, but you can't really go wrong I'd think with slathering it up with some excess oil if needed.