Engine was running fine and the next second it doesn't start.

Discussion in '2-Stroke Engines' started by core2kid, Jun 6, 2010.

  1. core2kid

    core2kid Member

    So basically I had this bike go for about 25 miles. It ran fine, mo problems. Just a hard start on the first start of the day but once it started, it ran like a champ. Today I had to remount the engine on a new frame (Wal-Mart replaced the defective tire and bent the axle at the same time. They wanted the bike back, wouldn't just replace hub.) and it ran fine.

    I rode around for about half a mile testing it out, stopping and revving it and it seemed to work. I headed over to my friends house (1/2 mile) and up the hill, the engine seemed fine. On the way down, I held the clutch and the engine died. At my friends house, I put in some gas thinking that I ran out. No luck, it still didn't start. I pedaled back home and I filled the tank 1/2 way with the fuel I used in the beginning. It started but was a very rough ride and then stalled. I started it again, which took about 3 minutes and then held the clutch and revved. It worked fine and revved. I let it idle for about 30 seconds and revved off and on. As soon as I lifted the bike and hit the gas to spin the rear tire, it stalled. Now it won't start again.

    Any ideas? I haven't tested the CDI yet but it's had less than 25 miles on it. I'd be surprised if it broke. The carburetor is also mounted properly and leaks out fuel when I open that screw on it. Gas tank drips out fuel fine. (Even tried w/o fuel filter with no luck)

    I've heard stories about the coil being bad. Do you guy's think that's the case? Does this seem electrical or an engine issue?

  2. Al.Fisherman

    Al.Fisherman Active Member

    I've had a coil go out within 3 days of installing. You never mentioned a electrical or compression check.
  3. core2kid

    core2kid Member

    I doubt it'd be something with compression since it ran then just stopped and still ran at times. Also since pulling the bike without the clutch engaged is just as hard as it used to be.

    The CDI at the settings 20M, 200K, 20K, 2K, 200 under OHM gave a reading of 0. I guess my CDI is dead. Do you think that makes sense?
    Last edited: Jun 6, 2010
  4. core2kid

    core2kid Member

    After I tested the CDI, I put it back together and it started right up and ran fine. I have no idea what the problem was but it seems to be working now. Any ideas what could have been the problem?
  5. G-Superior

    G-Superior Member

    could be bad connections(came loose or something like that)
    If it was my bike i would also change the plug because those chinese one fail really bad(not sure if yours is a chinese or not because you did not said anything about it but the only engines that have a cdi separate from the coil is a HT)
  6. core2kid

    core2kid Member

    Are the HT Engines better than the Chinese ones? I bought my engine from a US Seller on eBay.
  7. KCvale

    KCvale Motorized Bicycle Vendor

    The CDI wires coming loose are a common problem, they use crappy short wires to boot.

    I upgrade all my bikes now with my own little custom keylock CDI module add-on.


    It really shows how sad the stock offering in.


    Do it yourself part kits, assembled add-ons, and complete ready to drop in units including the CDI coming soon, I have the parts for 50 ;-}

    [​IMG] [​IMG]

    KC's Kruisers Glendale Arizona, USA
  8. GearNut

    GearNut Active Member

    The HT engines are the Chinese ones. "HT" is just a quick to type reference to them.
    Happy Times as it means.
  9. core2kid

    core2kid Member

    I like the keylock CDI, it's probably something I could end up doing myself, I'm pretty confident in my electrical abilities. As for the connectors coming loose, I ended up tightening them with a plier and electrical taping them together. There's gonna need to be some serious vibration before those come loose again.

    I purchased the kit on eBay from a seller called rawmotorsusa. He doesn't have the engine for sale anymore though. The title of it was:

    He is a seller from CA. How can I tell if it's a china engine?
  10. GearNut

    GearNut Active Member

    Does it look like the in frame engines in a lot of the bikes in the photo section?
  11. KCvale

    KCvale Motorized Bicycle Vendor

    I should have the DIY "bag of parts" up on my web site for $19.95 and just a couple of bucks to ship it you are in the US soon.

    A pretty good deal considering how expensive the box and switch are to buy one at a time, if you even can.
    I had to buy 50 of each to even get them, and 100' spool of that cool wire and I can't use them all, but I'll get to that when the site is ready to take PayPal orders for it.

    [​IMG] [​IMG] KC's Kruisers Glendale Arizona, USA
  12. motorpsycho

    motorpsycho Active Member

    you should just cut off those push together wire connectors and solder all of your wire connections. even tho you squeezed them together with pliers and taped them, they will still break eventually.
    just get rid of them, and solder the wires. then cover the wires with heat shrink...this will save you headaches later on.
    you should also check to make sure that none of your wires have bare strands sticking out of the ends, or worn insulation. one strand of bare wire touching the frame or anything metal will give you ignition problems.
  13. core2kid

    core2kid Member

    I never thought of the bare wires, I'll check that. As for starting, I felt that if I choke it and prime it, it usually starts so I'm lost.

    Here are some pictures.
    Fuel Filter Installation (Is it the right way?)

    Exhaust Leak (Lots of black liquid, assuming it's the gas+oil leak from there) Could that be causing problems?

    Engine Mounted

    Wiring from Coil to CDI and Kill Switch.
    Last edited: Jun 7, 2010
  14. GearNut

    GearNut Active Member

    The filter is installed bass ackwards. The current way will allow it to clog up alot faster as it strains the dirt and crud out.
    The black goo means that you have a leak where the pipe bolts up to the cylinder.
    Not a huge problem, but a real mess maker when the goo gets blown back onto the engine, bike, and you.
    The wires are connected correctly, but cut off those darned stock connectors and solder each connector and seal each with heat shrink tubing. Those stock connectors are a major cause of headaches with these engines.
    The white wire BTW is a low power (3 watt, 6 volt) output for powering lights, not a method of killing the spark. It can be used for killing the spark, but that is not why it is there. Connect the yellow/red wire to the black wire instead.
    FWIW.I do not even use a kill button. I either pop the clutch out with the engine idling, or reach down and turn on the choke, suffocating the intake.
  15. core2kid

    core2kid Member

    Well I used to pop the clutch out and kill it that way but I thought why not use the kill switch if I have one.

    On the first start of the day, how should I start it? Should I hit the primer button on the carb, flip the switch up and start it and then put it down?

    Could the fuel filter be causing the problems? I really want to know why I'm running so roughly.
  16. core2kid

    core2kid Member

    Tomorrow, I'm going to go ahead and fix the exhaust leak. Somebody told me that the engine needs that back pressure to work well. I'm also going to go ahead and check all the wires and solder them too. The white wire I'll just electrical tape and leave tied to the frame. Would I get voltage out of the white wire right now or would I need an additional part?

    I'm also thinking about buying the pull starter for the engine. It'd help in testing spark plugs and coils. Do you know how it works? Would I hold the clutch and pull start the engine?
  17. GearNut

    GearNut Active Member

    You can get voltage out of the white wire right now. it is AC current though. Most can power one light, not very brightly though.
    I never use the primer button. I just go full choke untill it starts, then I pull in the clutch and stop, fiddling with the throttle to keep it running. I use 1/2 choke or thereabouts, holding the throttle for a fast idle until the engine is warmed up, reducing the choke to full open position. It takes about 2 minutes.
  18. core2kid

    core2kid Member

    I used to start it without having to use the choke but I think I might have just been lucky. I'll try to start it today with the way you said and see if it kicks in. About how many tries does it take to get the engine running in full choke for you on the first start of the day?
  19. GearNut

    GearNut Active Member

    Every engine likes a different approach, you will have to experiment with yours to see what it likes. I can start mine within 50 feet of letting the clutch out while pedaling at a good speed. Sometimes it fires up immediately, and other times it is moody for the first 40 feet.
  20. core2kid

    core2kid Member

    Thanks and last question GearNut, is my engine the china one? I posted a picture of it.