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Post by nofxortiz on Mar 16, 2013 17:39:06 GMT -5
Hey guys, i'm trying to cover all my bases and figure out whats wrong with my tao. This is my 3rd scooter and I've repaired and sold my first two so I have a very small amount of knowledge. I just recently purchased a Taotao ATM50 with only 77km on the odo off craigslist that wasn't running. It was purchased by the original owner in Aug. and hasn't been running since Dec.
It cranks but doesn't start, and first when I opened it up I saw the carb has been pretty damaged from trying to force the throttle open to idle higher. It looked as though they tried setting the valves as the fan case was missing a screw and was loose and same with the valve cover. When I replaced the original stock spark plug it looked pretty burnt and that made me think the guy tried to start this thing over and over and made me think possibly the ignition system was fried. I checked the NGK plug I installed to make sure it was firing and it was(I assume that means the coil is also functional?). I checked all voltages and resistance and to my knowledge the CDI is fine.
I Replaced:
-carb
-spark plug
-battery
- all the lines just to start fresh
Also replaced old oil with fresh engine/gear oil and set the valves to .003/.004.
After all this was done, I was attempting to start it and it cranked but then would only make a buzz noise coming from near the valves. I kept trying to start it and a clank noise came from the engine and then it wouldn't do anything when trying to start it. After this I tried the kickstart but it was locked up. The clank noise maybe from when it locked up as the kickstart would rotate earlier. It seems theres an issue with the transmission now as it's locked and I am at a loss where to go next with this.
I'm doing a lot of reading to become more acquainted with the CVT because I do not understand where all these weird noises are coming from when I started, especially the buzzing and no cranking when I attempt to start it. Any help would be appreciated guys to get me in the right direction as i'm pretty lost at this point.
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Post by payneib on Mar 16, 2013 18:01:29 GMT -5
At a guess, I doubt it's the transmission that's locked. I'd suggest changing the engine and trans oil. Check both for debris (I doubt you'll be able check the engine oil for debris: if he's killed the engine in 77Km it'll probably be the original Chinese gunk in it). Get the valve cover off and check the valves and rocker gear for free movement, then get the belt and CVT covers off and see what you can move by hand. Hopefully you'll then be able to get it TDC and check the valve heights properly.
It could just be that repeated failed starts with no valve movement has air locked the cylinder. It could be a jammed ring or other mechanical failure if he's not run it in properly.
It does sound like thing has had zero TLC and may need some work.
Ian
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Post by nofxortiz on Mar 16, 2013 18:10:28 GMT -5
At a guess, I doubt it's the transmission that's locked. I'd suggest changing the engine and trans oil. Check both for debris (I doubt you'll be able check the engine oil for debris: if he's killed the engine in 77Km it'll probably be the original Chinese gunk in it). Get the valve cover off and check the valves and rocker gear for free movement, then get the belt and CVT covers off and see what you can move by hand. Hopefully you'll then be able to get it TDC and check the valve heights properly. It could just be that repeated failed starts with no valve movement has air locked the cylinder. It could be a jammed ring or other mechanical failure if he's not run it in properly. It does sound like thing has had zero TLC and may need some work. Ian Thanks Ian, I forget to include but yes I replaced both engine/gear oil and set the valves before all this. Yes this scooter was treated horribly and suspect it has more miles than the ODO says because the speedo cables was loose on the puck when I checked. I'm thinking possibly every problem but the no-start was created by myself, I replaced with a new carb from scrappydog. When checking to see if fuel comes from the drainage tube only a very small amount comes out. Im not sure of the drainage tube screw should be open or closed by default but the way the carb came it seems its not letting gas into the drainage tube. Also one other thing is when sucking on the vacuum tube from the petcock I can't get any fuel to come through, is this symptom of the petcock or possible some setting on the carb that I did not change from it's default? I seemed to rule out all fuel/air issues because I was under the assumption it was electrical but maybe I should go back to the basics, I need to get this engine un-locked first. EDIT: Okay managed to get it unlocked and cranking again if jumper cables are used, back to zero but still not sure why it won't start. |
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Post by payneib on Mar 17, 2013 3:35:07 GMT -5
I've not got a lot of scooter experience, but do have plenty of general engine experience.
I'm going to have to sit down and think about this one tonight. First thought was, when you changed the lines, did you check the tank for the remains of a Chinese factory workers lunch?
I'll get back to you later,
Ian
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Post by tvnacman on Mar 17, 2013 7:28:25 GMT -5
is the battery fully charged ? if it is not the starter will not push the bendex/starter clutch out to engage . Your going to need to check the ignition system for power (power and pulse) . I would remove the cvt cover .
John
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Post by nofxortiz on Mar 17, 2013 17:25:48 GMT -5
is the battery fully charged ? if it is not the starter will not push the bendex/starter clutch out to engage . Your going to need to check the ignition system for power (power and pulse) . I would remove the cvt cover . John Battery isn't fully charged, I've been jumping it in attempt to start it as the battery died fr repeated start attempts. Actually taking the battery in right now to get charged to see if its in adequate shape. I actually just did take of the CVT cover to check to see if bendix is engaging. I spun it manually and it didn't seem to be a problem however I am not sure, this was the first time this CVT had been taken off so I was just hesitant to start thinking its a CVT problem as this scooter seems brand new. If by checking the ignition system for power and pulse you mean the CDI, I've checked it repeatedly as it seems as if its the only thing left to check as everything else seems fine. This battery charging is a last ditch effort, if it doesn't work I'm out of ideas. Thanks guys |
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Post by teddy554 on Mar 17, 2013 17:58:56 GMT -5
What i would do is make sure all the timing marks are lined up and when you suck on the vacuum line gas should flow freely from the petcock on the petcock if located on the bottom of the tank the bottom nipple is vacuum and the top is the gas line
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Post by payneib on Mar 17, 2013 18:31:39 GMT -5
I've read through your stuff again mate, and I'm still leaning towards fuel supply/vacuum.
Fuel filter? Lines connected up the right way? (Won't say old lines-I know you replaced them) Petcock? Vacuum blockage from debris in the lock up?
I'm sorry I can't help further.
Ian
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Post by tvnacman on Mar 17, 2013 18:43:00 GMT -5
if you think its fuel , you can inject some fuel in the intake . Then crank it see if it spudders .
When the cvt is off you need to hold the bendix shaft to hold it in place .
John
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Post by nofxortiz on Mar 17, 2013 19:03:26 GMT -5
I've read through your stuff again mate, and I'm still leaning towards fuel supply/vacuum. Fuel filter? Lines connected up the right way? (Won't say old lines-I know you replaced them) Petcock? Vacuum blockage from debris in the lock up? I'm sorry I can't help further. Ian Hey guys, yes originally I thought it was a fuel problem but I didn't understand how petcock worked. I suck on the vacuum line and gas flows through the fuel line to the carb freely, I thought it was supposed to flow through vacuum line being sucked on. But yeah the petcock works perfectly and gas flows freely. I thought possibly maybe it was flooded, so I drained the bowl and started over again but same result. I'm pretty confident its not a fuel problem now from the research I've been doing, ive also drained all old gas and put fresh gas in the tank just in case. EDIT: Also for re-checking the electrical for possibility of it being the problem, I replaced the fuse and checked all wires. I assumed the lights wouldn't even turn on however if it was an electrical problem from looking at diagrams in the thread explaining how to check your CDI/Stator. I'm not too sure what else I could do for the electrical components besides replacing them entirely. The fact that it cranks strongly and doesn't start is making me believe its a starter motor issue, but the thing hasn't been opened before so I wouldn't see why it would be spinning in the wrong direction. Unless defective starter motors are common, but the original owner had it running before it died so I didn't think this could be the problem. |
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Post by tvnacman on Mar 17, 2013 19:10:08 GMT -5
Nof all you have to do is ask .
John
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Post by nofxortiz on Mar 17, 2013 19:32:29 GMT -5
Nof all you have to do is ask . John John, thanks for the help. Yeah i've tried injected fuel and seeing if it'll crank but it doesn't seem to make a difference. I was thinking about trying that method of taking out the bendix and attaching a drill to the variator to manually start it to see if that helps, I don't have access to a drill at this moment. The only thing I can think of that might be diagnostically relevant is the slight "popping" I get when trying to kickstart it. It's not very loud, and i've read thats symptomatic of a rich mixture or flooding but the scoot hasn't even started so i'm not too sure of that. This could also be a vacuum leak like others have stated but i've examined and re-examined every cm from the intake manifold to the carb to the airbox and I don't see any hint of crack or somewhere that isn't sealed. Everything looks in new condition. |
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Post by tvnacman on Mar 17, 2013 19:44:06 GMT -5
take off the carb and intake , crank it and dribble some gas down the hole .
Have you checked the valves ? what about the plug wet dry clean dirty ?
John
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Post by nofxortiz on Mar 17, 2013 20:07:13 GMT -5
take off the carb and intake , crank it and dribble some gas down the hole . Have you checked the valves ? what about the plug wet dry clean dirty ? John I've checked the valves twice and gapped them at 0.003/0.004, there wasn't any indication of damage to the rocker arm either. When I replaced the plug originally with an NGK the plug was dry and charred, and when I checked the new plug for spark today it was still dry and clean (does spark). |
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Post by teddy554 on Mar 17, 2013 20:16:06 GMT -5
Is the motor in time is the piston top dead center with every timing mark lined up
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