Clinician
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150cc
by: classacted - Jun 26, 2023 12:35:25 GMT -6
Post by classacted on Jun 26, 2023 12:35:25 GMT -6
when that happens, pull off the gas cap right away. if you hear suction, then it starts immediately, you are developing a fuel vacuum that is preventing enough fuel from getting to the carb.
this may also be an overheating issue with the passage of time allowing the engine to cool off.
those ideas are off the top of my head.
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Post by classacted on Jun 16, 2023 17:20:24 GMT -6
I use a good ol compression tester when I adjust the valves. it's tedious, but guaranteed. when I'm done the compression can not be lower than when I started. it can only be equal or better. when I start I do a compression test and every time I do an adjustment I put the head back on and test again. it's only four 8mm bolts, and to be certain I have the valves at the best possible adjustment is worth it IMO. putting the head back on ensures that the oil goes where it has to go. right now my compression is at 137 psi, which is what it was when it was new.
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Clinician
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150cc
by: classacted - Jun 16, 2023 17:06:31 GMT -6
Post by classacted on Jun 16, 2023 17:06:31 GMT -6
if I ever buy another, the placement of the gas tank is going to be a major consideration. gravity reliably delivers the fuel to the carb, and I won't use a vacuum petcock either. that petcock is supposed to save you in case of an accident. it's supposed to stop fuel from going everywhere when you dump the bike, but I think it's more likely to cause an accident when it fails. the time I used one, it failed in five days. it's been almost a year since the bike died on the road and it was because of that petcock.
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150cc
by: classacted - Jun 12, 2023 19:22:11 GMT -6
Post by classacted on Jun 12, 2023 19:22:11 GMT -6
bummer. I am looking at a BMS heritage manual and it shows the gas tank under the seat, just like my tao tao, but can also be under the foot platform. I know some bikes like ice bear mad dog require a fuel pump. I hate that design. these things are supposed to be practical. from what I have read, kymco is similar with a vacuum pulse fuel pump.
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GY6 180cc
by: classacted - Jun 11, 2023 20:50:03 GMT -6
Post by classacted on Jun 11, 2023 20:50:03 GMT -6
I hope the original poster solved his problem. I don't think he/she is going to reply.
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Clinician
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150cc
by: classacted - Jun 11, 2023 20:44:22 GMT -6
Post by classacted on Jun 11, 2023 20:44:22 GMT -6
as soon as I got a manual shutoff valve, I ditched that vacuum shutoff thing. it took about a week. haven't looked back. the same thing goes for that EGR system. the chinese know what they are doing when they make the vehicle so hard to fix. most people just get rid of the vehicle and buy another one and that's what they are hoping for. don't forget to have an inline filter.
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Post by classacted on Jun 9, 2023 8:50:19 GMT -6
if you have ever sand blasted then you know how that sand goes everywhere. the magneto, ignition switch, kill switch, etc, may be effected by dust. I don't think they are sealed. it seems the coil and the cdi units are. there is a square on the flywheel that triggers the cdi unit that is exposed to the elements. I used to ride mopeds that had breaker points and if outside air was allowed at the points, they would burn quicker. points can be redressed, which is using sandpaper to remove the burnt metal, then use white paper to remove dust which is crucial. I actually made my own effort to seal the compartment, but they never lasted over 16 hours of running time before they needed redressing. I would be riding along and suddenly the moped would 'pop' and lose power. if I kept riding it would get worse until it died completely.
when I received the moped the points were already burnt and I didn't know how to get new ones. a guy told me breaker points come with a hard coating that takes a while to burn, but once that happens, dressing them is only a temporary fix. the advancement to electronic ignition was a huge move in the right direction.
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Post by classacted on Jun 6, 2023 9:49:56 GMT -6
got it. I learned something new. did you ever find the culprit? if not, my bet would still be on that woodruff key.
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GY6 180cc
by: classacted - Jun 2, 2023 20:32:43 GMT -6
Post by classacted on Jun 2, 2023 20:32:43 GMT -6
you mean IT WON'T FIRE. you are stating that the starter is moving the piston and you're not hearing that 'pop' when the engine takes over by itself. correct me if I'm wrong. that's called a 'crank, but no start'. if you have a compression tester test for compression. 120 lbs is marginal IMO.
if you have well over that, I would suggest disconnecting the air filter and exhaust so it can breathe, then pulling the spark plug out and wiping it off so it's dry. crank the cylinder to shoot gas out because it could be flooded. if it's totally dry, find a way to squirt a little gas directly in the spark plug hole.
did you loosen the screw on the float bowl to see if there is gas in it? how old is the gas?
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Post by classacted on Jun 2, 2023 20:08:57 GMT -6
did you inspect the underside of the engine 100% and no damage found?
if you replaced the starter clutch, then you saw the chain underneath. at least MY gy6 150cc has one. I would suspect yours has one too. that chain is the first thing I would suspect. there may be a woodruff key on the crankshaft somewhere and if that has failed somehow, you are very lucky.
bummer what happened to you. I've had several ugly mopeds stolen myself. I know how it feels.
you may end up removing the magneto and covers on both sides, but hopefully there will be no major damage. |
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Post by classacted on Sept 20, 2022 13:54:57 GMT -6
when a moped runs out of fuel, just before the engine dies it will rev to high rpm's. my first check for that symptom would be fuel supply. all the way from the tank to the float bowl. obviously, if the gas tank vent is plugged, fuel will not flow.
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Post by classacted on Sept 19, 2022 16:00:04 GMT -6
you don't give alot of info about the vehicle. check the condition of the spark plug and the gap. check for spark.
loosen the exhaust bolts and put a screw driver between the exhaust and cylinder. you could still have an obstructed port - check the port (carbon). after each task see if it starts and runs correctly. remove the air cleaner. make sure the spark plug cap is not coming off the plug. gy6 is notorious for this. make sure your valves are within acceptable range. I had problems with this just last week. spent a whole day making adjustments and retrying just to be 'good at it'. when the engine started without giving throttle I was happy with it.
still no luck try this to check if it's getting fuel. DANGEROUS. spray gas, wd40, starting fluid, etc in the carb intake and crank to see if you're not getting fuel. it won't run for long.
I also remove the vacuum valve on my bike. I let the fuel go directly from tank, thru filter, to carb. totally removed the valve.
if your gas cap is defective (not venting), vacuum will develop in the tank and fuel will quit flowing. as soon as it dies, pull the cap to hear if it sucks air.
whenever I have a carb issue, I just remove it, disassemble it, and put it in an ultrasound. this has always worked for me, and I am talking hundreds of times. I don't change any parts from stock.
don't forget good ol water in the carb and the tank. the gas station LOVES putting as much of that in your gas that they can get away with.
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Post by classacted on Sept 19, 2022 15:27:10 GMT -6
it looks like your engine was unable to breathe.
that is normal for carbon to fill the exhaust. being cheap, I would drill holes in the muffler then plug them with a screw one at a time and take the moped for a ride. when I saw that the moped didn't have as much power I would remove only the last screw and call the repair complete. a plugged exhaust can cause the moped to lose power or die completely on the road and NOT restart. if this happened to me I would remove one of the screws. there is a port from the cylinder to the muffler that needs to be kept clear too. I would never buy a new muffler. mopeds are supposed to be cheap. I think using a car is cheaper than buying parts unnecessary.
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Manuals
by: classacted - Aug 12, 2022 14:51:44 GMT -6
Post by classacted on Aug 12, 2022 14:51:44 GMT -6
there is a website and a company that still sells them and I am 95% confident that the engine and trans is the gy6 platform. any gy6 shop manual you find online will probably help you to get it to run. I was able to find a fantastic shop manual for a gy6 scooter called 'arrow' that I never heard of loaded with detailed info free.
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Post by classacted on Aug 12, 2022 14:25:15 GMT -6
I don't have the powermax. I have the quantum, but every engine part that matters is probably the same, and when you consider what you get for the money, I am actually impressed. other bikes are WAY more expensive. I have a japanese moped collection and I know they are a high quality item. I only have 700 miles on the tao tao so far, so there will probably be problems. the thing does 60 and I haven't even gone full blast yet. I only recommend it if you have a healthy dose of cowardice like me. I'm scared every time I get on it, but I love it. I want to get out on a nice highway with no cars around, but that hasn't happened yet.
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