So I have a 110cc Honda trail. It has been getting colder where I live and my bike has been acting funny.

first problem: At FULL throttle it starts to sputter and crackle.

The second problem: does not idle properly

I was more or less fine with these things for now as I am super busy with homework and school

My third and final problem: I want to go for a night ride and it was very cold. For the life of me, it wouldn't start. I was getting fuel on the ground from my carb overflow line from trying to turn it over for 10+ min. but when I sprayed butane in the engine as a last-ditch effort it starts so EASY and felt really dumb.

So if you could help me with any of these problems I would be super grateful.

EDIT: I don't think it would be a carbon build up given that the engine has only been used MAX three months. But I think that it would be worth it to check it out :) Also I just removed my carb to check the jets and them were super clean.

  • 1
    You mention "clone" engine - details to give us info to be able to help
    – Solar Mike
    Commented Oct 2, 2017 at 4:28
  • well, I think it is Chinese but I do not know if it is a liffan or just a knock-off knock-off. Oh yes and it is pretty new Commented Oct 3, 2017 at 14:45
  • @aidanzollner 1. This has only been happening since it got cold? 2. Did the sputtering and such improve as the engine warmed up? Commented Oct 3, 2017 at 22:09

1 Answer 1


Your bike is full of deposits -- carbon and varnish -- that are byproducts of petrochemical fuel and years of combustion. Deposits clog fuel lines and carburetor jets, cause piston rings to stick, and effectively run the engine too lean (hard starting, loss of power, and more).

To fix the problem, start by spraying some automatic transmission fluid through the carburetor at high idle with a spray bottle. Do not spray so much to make the engine stall. Spray for five minutes while the engine smokes.

Next, while the engine is warm, remove the spark plug. Pour an ounce of automatic transmission fluid through the spark plug hole and spin the engine over a few revolutions. Allow to soak 10-20 minutes, then spray carburetor cleaner all around inside the compression chamber. Immediately crank the engine some more with the spark plug removed. You will be amazed at the black carbon that comes out. Soak and spray at least two more times.

Replace the spark plug with a new one and start the engine. Lightly spray carburetor cleaner through the throat with the engine at high idle. Spray in one second bursts for five minutes. Find the small carb. jet and spray it directly with the engine off.

Finally, add two ounces of automatic transmission fluid per gallon of gas and run the bike normally, with lots of low-end acceleration, but avoid full throttle for a time. When warm, rev the engine and shut off immediately for 10 minutes (heat soak). Continue using at least two hours over the course of at least two days. Then fill the tank with fresh fuel, this time adding one ounce of acetone per gallon and continue running engine for more hours.

If the bike has crankcase oil, change it and substitute 20% with atf. Change the oil again after an hour of usage and continue using the atf. Change the oil a third time after two more hours of run time.

If this procedure doesn't help, you have an induction leak. Replace old carburetor and intake manifold gaskets. If there are any vacuum hoses, change them as well. You can check the gaskets for leaks first by spraying them heavily with carburetor cleaner while the engine idles, looking for any change in rpm.

I have read that if the intake manifold gaskets are leaky, and you run the engine full throttle for more than a minute, you will overheat and damage the engine badly.

  • Off topic: if we we're to do this in a modern car for carbon clean up. What are the disadvantages with catalytic converter and evap system. Commented Oct 2, 2017 at 10:18
  • @NumairAidroos - How is this answer off-topic? Only questions can be off-topic. Besides, the question/answer is about what to do for a motorcycle which doesn't have a cat or evap system, not about modern cars. Commented Oct 2, 2017 at 20:59
  • Paul, I'm asking him an off topic question. Well, since you're here. Why don't you answer? If we add ATF in to a modern gasoline combustion engine, fuel tank, and a fine mist via throttle body inlet, what is the gain, loss, and probably damage? Commented Oct 2, 2017 at 23:48
  • I understand you, Numair. The same same gains apply to a modern car as with the dirt bike. The catalytic converter will not be damaged. I know because I do so I my cars, even a late model Mercedes-Benz E350. The only slight disadvantage is that misting ATF in heavy dose through the throttle body will stain the spark plugs a little black, and should ideally be changed. If you use it solely in the gas tank, even at 2 oz. per gallon, there is no issue whatsoever. You can accelerate cleaning rapidly by adding acetone to the fuel at a rate of 1 oz. per gallon.
    – Carguy
    Commented Oct 4, 2017 at 2:07
  • I've confirmed the safety to the cat. converter through research on the Internet. I have fixed multiple vehicles and many problems, such as rough/uneven idle, ping (detonation), poor acceleration, poor gas mileage, foul exhaust smell, and high head temperatures.
    – Carguy
    Commented Oct 4, 2017 at 2:21

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