125cc Super Cold Blooded

Discussion in 'Lifan' started by Korbon_Dallas, Oct 26, 2020.

  1. Korbon_Dallas

    Korbon_Dallas Member

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    I have a Lifan 125cc that I bought new on Amazon in 2014 for $210 even with the carb, manifold, harness, angled air filter, and everything else. I did pick it up at their store so saved shipping. Even at 100 degrees outside when I start it cold with choke on, let it run until it starts to die (even reving), then take choke off it’ll die at idle so I either turn the idle up for a few minutes and let it warm up or keep reving it for a while until it idles perfectly, but even then when I rev it pops for a a couple minutes, but after another minute or so it idles and runs perfectly. Just kinda weird as popping usually means carb adjustment but I’ve tried doaling it in better but it just gets worse I just decided it’s super cold blooded. Anyone else’s do this? Wish I’d bought two as complete ones like mine have practically doubled in price. I did buy 3 Predator 212cc’s in 2012 as they were only $79 when they first came out. 2 are still running strong and the other only broken in but never installed in anything.
     
    #1 Korbon_Dallas, Oct 26, 2020
    Last edited: Oct 26, 2020
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  3. racerx

    racerx Administrator
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    That cold-blooded character means one thing...it's running lean when cold. That's functionally, operationally, lean. The same amount of air & fuel that's optimal when the engine & induction assemblies are fully up-to-temp can, and usually are, terminally lean when cold. Less liquid fuel is vaporized when cold and liquid fuel doesn't burn, leaving you with a lean mixture. Once the engine is hot, most, if not all, of the incoming liquid fuel vaporizes by the time the spark plug does its stun gun routine. So, while cold, with only a small fraction of the fuel being burned, you have to dump in enough additional fuel to make up the difference.

    Based on your description, I'd try turning the pilot airbleed (a.k.a. idle air control) screw 1/2- 1 full turn clockwise. That'll decrease the amount of air in the pilot (idle) circuit producing a richer idle mixture. If that cannot be done before the pilot screw is less than ~1/2 out from seated, you need to upsize the pilot jet.

    Generally speaking, these engines perform best with the idle fuel mixture near the rich limit. That usually covers the range from cold to hot without fouling the plug in normal idle situations.
     
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  4. OLD CT

    OLD CT Well-Known Member

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    Post up a picture of the carb, I might have a bigger pilot jet for it around here. If it is the same carb I use on the lifan 140.
     
  5. Korbon_Dallas

    Korbon_Dallas Member

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    Thanks. I think I'm gonna sell it instead of my CT70K when I get my new Honda CT125 ABS, but I drove it all around our 500 home gated community last night and had a blast. Even the headlight was bright at 1/2 throttle! Lol. Instead I'm gonna sell the XR70 with Lifan 125 4-speed that I built. Also, the CT70's are a good investment and increasing in value every year! Btw. I might've been a little harsh on Kirby too. I didn't read his response to my reply, but I just thought the Zombie thing was funny, and there was no reason to use the word 'Stupid' in a reply. Here's the XR70. 70.JPG
     
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  6. Korbon_Dallas

    Korbon_Dallas Member

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    I've got the air screw adjusted as optimum as I can get it. It's amazing how much difference that adjustment will make compared to the one on my CT70.
     

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