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Pit Bike Won't Start

Discussion in 'Technical and Troubleshooting Torque' started by Sam__0397, Jul 4, 2015.

  1. I've had this 125 for about 3 weeks that I bought used. I rode it once for a day and it started first kick. the next weekend I went to start it, only to find that it didn't want to. I had a mate check the electric components with a multimeter and that's all fine. I have tried starting it with and without using throttle, and with the choke both on and off. Nothing seems to work. The carby is clean as far as I know of, but I suspect that it may be a fuel issue. Its an Xmotos Chinese bike with a Lifan engine. Any help would be appreciated as I don't know a whole lot about bikes.

    I recorded a video to show what's happening:

  2. As long as the engine is ok and the timing is right an engine needs, air fuel and spark. If u say your mate checked and it's getting spark then maybe it's fuel. Undo the fuel hose underneath the tank that runs to the carby and check that fuel is getting to the carby
  3. Yep just checked, fuel is definitely getting into the carby.
  4. If it is getting fuel, then remove the plug lead to double check you are getting spark when cranking. If you do get spark then it may be worth a quick check to see if the plug is fouled and needs to be cleaned.
  5. The bike is getting spark, I cleaned the plug and still no luck.
  6. Okay I think I may have found the problem but I still need some help. I drained the oil and it came out disgusting, I just need to know what to use to clean out the oil tank.
  7. Haven't heard about having to clean out oil reservoirs before. I would be worried in using any solvent in case it damaged the clutch friction plates. Some of the more mechanical skilled guys may have an option. Personally I would replace the oil filter, fill the bike with the normal oil you use and go. If you are really worried you could try a cheaper oil first and then a second oil change.

    The dark kludgy colour means it has had a modern oil with detergents in it so it has been cleaning the engine and holding the small particulates in suspension so the filter can filter them out.
  8. Oil won't stop it starting, not unless it's a 2-smoke and the oil drowns the plug.

    A petrol engine needs 5 things to run;

    You have established spark, and presumably based on there still being some resistance when you try to kick it, compression.

    That leaves timing (4 stroke) air and fuel.

    Do this;
    remove air filter
    get 5-10ml of fuel
    remove spark plug and ensure it is clean, earth the outer hex part of the spark plug to the head while you kick it over (should be easy to kick with plug out) to verify there is a nice spark, and ensure the gap on the plug is wide enough to show a decent spark. It if is too narrow or wide, spark will be weak or non-existent.
    If spark is good, tip the small amount of fuel into the plug hole and promptly re-insert the plug, tighten it down.

    Now kick it a few times with zero throttle to start with, and if nothing happens, not even a cough, then a slight throttle opening and kick a few more times.

    If it runs, the air filter is choked and not allowing air to the carb so shut it down and clean/replace air filter before re-installing it and repeating the above process.
    If it coughs or runs for a couple of seconds and dies, then you have a fuel issue with fuel not likely getting to the carb, or the carb not metering correctly, which will probably need you to get the carb cleaned/replaced but as you have no knowledge in this area, I won't go into how that's done. I would also say check for a fuel filter, probably not present on a cheap Chinese piece of shit, but if it is, remove it and try run it again to eliminate it as a cause.
    • Like Like x 1
  9. I should add that my assumptions are also based on the thing not having skipped a tooth on the timing gear if its a 4 stroke, but we can get to that if need be.
  10. It is possible the fuel is stale. When it goes off it can also coat the plug insulator preventing the plug from igniting the fuel. So if the fuel is old, drain the tank on put in fresh juice. f it still doesn't start try a new plug.

    Both these potential fixes are rather inexpensive so worthwhile trying now

  11. It started for a few seconds when I poured fuel in the plug hole, so its definitely the carby. They are about $30 to replace so I think I will just buy a new one. Is this the best way to go?
  12. If you can replace it for $30, I wouldn't be bothered mucking about with the old one.
  13. Alright, I got it working and I have no idea how. A friend jumped on and gave it a kick, but it didn't cough and die after a few seconds, he gave it some hard revs and after that it was idling smoothly. I'll still replace the carby to be sure that the bike doesn't fcuk up again though. The cops didn't like it though, hopefully I don't get charged O_O