Can't start my motor, tried everything???

Discussion in 'Motorized Bicycle Trouble Shooting' started by Death Machine, May 28, 2012.

  1. Death Machine

    Death Machine New Member

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    Hi everyone thanks in advance for any help that i can be given :)

    I have a chinese 2stroke, shift kit and x chamber. My bike's been running fine for months now but the other day it just died while i was riding along. No coff, no splutter no backfire just died. I had this happen before and it was a faulty coil so that was the first thing i checked. Pulled the plug and sat it on the head as i kicked it over and it had spark. Non the less i replaced the coil and cdi with a brand new one but still made no difference. Tried multiple spark plugs and leads and boots but no difference.
    I figured it must be fuel. rebuilt my carb (but it looked fine inside) Sealed it all with Hylomar gasket jointing compound as well as to the intake plus an O ring to make sure it was all airtight. Resealed the intake to jug too.
    Drained the old fuel out of the tank and checked the filter inside. All fine. Checked my inline filter and fuel hose by blowing through it but it was also fine and unblocked. I just got some new fuel mixed at 32/1 with a good synthetic 2 stroke oil (same as always) but it still made no difference. My plug is wet and stinks of fuel so i know it is getting fuel.
    Now i have a boost bottle. I was wondering if there was a leak there, even just the slightest of leaks would it cause it not to start???
    I've got full compression with no leaks in any gaskets at all. This bike is my transport and been running great for a while but i now have a real headscratcher.

    If anyone needs anymore info please just ask. I am even pretty handy with a camera too if needed.

    Cheers again everyone and keep up the good work :)
     
  2. Al.Fisherman

    Al.Fisherman New Member

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    Thanks for being specific on what you have done already. Sound like you have just about checked everything...well except the one thing causing your problem. But what engine (sounds like a Chinese HT) are you running and what carburetor is on it. A small vacuum leak doesn't sound like your problem. Plug being wet and you have spark leads me to believe the engine is out of time. Check to make sure the woodruff key in the magnet is intact.
    [​IMG]

    Also dry out the fuel in the engine case, and off the plug, and try a squirt of starting fluid or throttle body cleaner to start it.
     
  3. Joel G.

    Joel G. New Member

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    Take the boost bottle away and try it?? Start undoing things and you'll get it.
     
  4. Death Machine

    Death Machine New Member

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    Thanks for the awesomly fast replies fellas!
    I'm running a 70cc chinese HT, Superhawk R80 with a speed carb.
    I didn't think that a slight air leak would cause a complete no start.
    I just had some dinner but i'm about to check the woodruff key. I know the magnet looks pretty good but haven't spied that key yet so till i do...
    Another thought is it possible for the wires from the coil to the cdi to maybe arc somewhere and earth causing the no start and if so is there a way to fix it?

    Cheers :)
     
  5. Death Machine

    Death Machine New Member

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    had a look at the magnet and woodruff key and it's all there and in the appropriate position. Also thought the exhaust might be blocked so i pulled that off but it's also all good.
    I'll have to get some 'startyabastard' and see how i go.
    I'll keep things posted as i go along.

    :)
     
  6. Al.Fisherman

    Al.Fisherman New Member

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    Check all connections, and remove the white wire, or at least isolate it good.
     
  7. robbomberbomyea

    robbomberbomyea New Member

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    id also disconect the kill switch could be bad, then try and get it to start.good luck
     
  8. Death Machine

    Death Machine New Member

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    I've had the multi-meter out and ran it over all my connections, made sure i had a good ground and the coil and cdi were showing all the right readings.
    I moved the new cdi so i could connect it directly to the new coil. It's just 2 wires about 20cm long connected together. I've already cut off the white wire from the coil just to make sure. :-||

    :)
     
  9. Death Machine

    Death Machine New Member

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    It's a funny thing with the kill switch. Every time i've had it connected about a day later i have blown a coil. I ended up doing 2 of them. Sure enough the no start problem happened a day after i connected the kill switch again. It was the first thing i ranked out on the side of the rd lol. It's long been disconnected now, i wired it up to my headlight instead.
    It's an after market toggle switch from SBP which i might add is a pretty solid little unit. I've hardly ever ran a kill switch i just usually stall it out when i stop, ithat's just no good when i spot the 5.0.

    Cheers
    :)
     
  10. locell

    locell New Member

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    if EVERYTHING external on it checks out OK, you may of lost compression, it wont start without compression. This happened to one of my motors once. It just wouldn't start, I checked it all. I replaced my Jug, piston, and rings and i was back in business. Get a compression gauge, you can do a tool loan at auto zone/checker/blah and check it.

    Compression just failed on me out of the blue, I wasn;t running it lean or hard or anything. The quality on china engines varies ALOT.

    I don't know what the compression should be on your engine exactly, id guess 160 or so but im sure another member on here knows a little closer on your exact engine.

    http://www.your-adrenaline-fix.com/compression-test.html
     
    #10 locell, Jun 4, 2012
    Last edited: Jun 4, 2012
  11. Greg58

    Greg58 Well-Known Member

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    I just searched and found that 145 to 155 should be close on the compression.
     
  12. Greg58

    Greg58 Well-Known Member

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    Did a little more searching and found someone had the same problem, had spark with the plug out but would not fire under compression. His was a bad ground at the magneto. So you might trya new wire from coil to cdi.
     
    #12 Greg58, Jun 4, 2012
    Last edited: Jun 4, 2012
  13. Death Machine

    Death Machine New Member

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    Hi everyone thanks so much for all the replies :)

    I removed the boost bottle and placed a bolt in the hole.
    Got a can of 'startyabastard' but the bastard wouldn't start. Took the air filter off too.
    I even went as fas as to try out my mates NT carb but it made no difference at all.
    Which leads me to think it's the motor. I'll get a compression gauge this week and i'll see where that takes me.
    locell i reckon you're onto something mate :)
    We're getting closer to the source!

    :-||
     
  14. locell

    locell New Member

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    drn2

    for a redneck, backyard test of your compression, get the bike all setup for starting, then pull the spark plug. Pour a bit of motor oil (the thicker and stickier the better into the cylinder via the spark plug hole, reinstall the plug and try to run it. The oil will increase compression temporarily and it will behave different. It will sputter or even run for a moment if the compression is the problem. Also if you get oil leaking from between the head and the jug that tells you something too.

    dance1

    laff

    .trk
     
  15. Death Machine

    Death Machine New Member

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    Hi everyone.

    I made an executive decision to buy a top end rebuild kit rather than a compression gauge and it paid off.
    I opened up my motor and found that one of the clips that hold the pin onto the conrod had sheared off and went up the side of my piston to make a beautiful mess! It ground two grooves right over the rings which fused them to the piston, creating low compression.
    My only wish is that i had pulled the barrel off first before i tried everything else but as anyone with a shift kit and x-chamber will know that getting these motors off a bike is a pain. Especially in a compact frame!

    Cheers to everyone that helped me out. Here's hoping that this thread will help out someone else in the future :)

    dance1
     

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