WD-40

When it cuts out you could remove the spark plug and check for spark. If there's no spark you know that's the problem. If there is spark it's a fuel problem. To me a gradual loss of power, then restarts straight away but down on power sounds like a lack of fuel. If you've ever run a tank dry you know the feeling of the power gradually dying as the fuel runs out. You have to give it more and more throttle to keep it running. If you stop the bike can't idle and cuts out. Dying because of loosing spark is a bit more of a sudden thing rather than gradual. That would be my experience anyway. You should check if you've got spark when it cuts out and go from there.

I've never heard of anyone going from fuel injected back to carb. I don't think you can just put a carb in a fuel injected bike and it works. What about the electrics for spark timing and advance? The ignition system on your bike is for fuel injection. If you put a carb on it I think you would need the ECU off the carb bike and the wiring loom to suit that ECU. Is the pick up the same on the carb and fuel injected bike? Would you need the pick up coil and maybe the rotor off the carb bike to make sure the spark plugs are firing at the right time? Then on the fuel side the fuel pressure is a lot higher on fuel inection. Would you need the fuel pump from the carb bike or bypass the pump and gravity feed the carb? I think you would have to swap the whole lot over to make it run properly with a carb. Fix what you've got. If you can't fix it let a mechanic fix it.

Looks like a throttle cable problem to me. When you release the throttle does it snap back to it's original position or does it move slowly? In your video the cable has quite a severe kink just after the adjuster. You may have routed it incorrectly or the outer sheat could be damaged. It shouldn't have any kinks. Kinks can cause binding. I would replace it. Even if it doesn't fix the problem at least you can rule it out and a throttle cable is cheap.

That's impressive. You could create any shape tank you want once it fits inside the 3d printer. Do you think it would be possible to print a whole bike in the future? Maybe it's the end of large scale manufacturing Instead everyone has a printer and prints off their own stuff

The question is then why do they set such a ridiculously short service schedule? Is it because they know very few people will follow it so they won't have to honour the warranty? Or are they so concerned that it is going to fall apart in the first two years that they have to check it ever four months? Either way it stinks to me.

Have you got a wiring diagram? I had a quick look and I can't see one so I'm guessing here. It would make it a lot easier if you have one. At the connector going to the ignition you should have a constant 12V. Which you said you have. On any of the other wires in the connector going to the ignition, have you got 12V only when the key is on and it goes to 0V when the key is off? This is the wire that powers everything. The wiring harness going to the ignition often rubs against the frame when you turn the handlebars so it rubs against the frame and causes problems. Turning the bars can also cause tension on the connector going to the ignition and that leads to a bad connection in the connector and sometimes burning in the connector. I've also seen wires corroded where they're soldered to the ignition barrel. Just so it's clear, for your testing put the meter to DC voltage and leave the black probe connected to ground all the time and touch the red probe where you want to measure for voltage.

I think people go for the Lexmoto because of the price but also because it's new so it comes with a warranty but look at the service schedule you have to follow or the warranty is void. 6 weeks 500km 4 months 1500km 8 months 4000km 12 months 7000km Every 4 months to 24 months so that's 16 months 20 months 24 months Then every 12 months after that. 7 services in the first 24 months or the warranty is void. All have to be carried out by a proper mechanic. Seems ridiculous or have I misunderstood? https://www.dundeescooters.co.uk/lexmoto-lxr125/

Nice bike

All modern 125s, even the Japanese brands seem to have dropped in quality. I think they all lowered their standards to be more competitive on price with the Chinese brands. If I was you I'd go for a used Japanese bike

Nice one Might be a good idea to take it for a short run and go through all the gears to make sure the gearbox is good before you take it apart

Good luck with it Stick a mudguard on or you'll be cover in dirt everytime it rains. I'd get a workshop manual and give it an oil and oil filter change for peace of mind. If you change the oil make sure you use motorbike oil. Car oil can cause the clutch to slip. Lubing the cables and levers can make a big difference to the ride. They get a stiff over time. Make sure you keep the chain in good condition too. The correct tension will be in the workshop manual. Don't over tighten it as that can cause damage to the bearings in the gearbox. Too loose and it can jump off the sprockets. Give the chain a clean and an oil to keep it in good condition. Check your tyre pressures.

The Haynes Chinese 125 is probably the closest you'll find. https://www.amazon.co.uk/Chinese-Taiwanese-Korean-Motorcycles-Powersport/dp/0857339206

If your bike is your daily transport I think a box is a must

It's rare that people report back with what fixed the problem. Most questions that are asked end up with no conclusion. It would make you wonder if it's worth replying to the questions.

If you're using a multimeter try putting it to dc voltage and put the black probe to the bolt on battery negative and put the red probe to the body of the starter motor. Push the starter button and as you push the starter button look at the multimeter. On a good circuit you would see 0V. If you see voltage higher than 0.5V it means there is voltage drop on the ground side of the circuit and your bad connection is on the ground side. You can do the same test on the positive side. Red probe to battery positive, black probe to the positive on the starter motor. If you see voltage when you push the starter button the problem is on the positive side.

So many people ask a question on their first post and never come back. Half the subscribers on here probably have 1 post

Yeah I agree with Mississippi Bullfrog, a single click from the starter solenoid is usually from a bad connection on the high current side of the starter solenoid. Could be at the battery, starter solenoid, starter motor or ground at the frame. Less likely but could also be a corroded wire on the high current side. The lights go dim because the voltage is getting dropped across the bad connection

Did you get the indicator working? What year is the bike? What colour are the wires on the connector that you don't know where it goes?

wet and dry sandpaper

I've always used the stringy ones from the pound shop and never had a problem with them. I've had a couple of them in a rear tyre at the same time for thousands of miles and had no problems. I've only had rear punctures. I don't think I would plug a front tyre.

It could be water damage on the circuit board. You could take the circuit board out and check from corrosion or broken traces.

There's a manual. Not sure if it's the correct year for your bike. Have a look at the colour diagram at the end. You don't have to understand it, just follow the colours. The left indicator is a two pin connector with a brown wire and a black wire. http://www.automotivespartsshop.com/file-download/YAMAHA-YZF-R125-SERVICE-MANUAL.pdf

Honda CBF250?

Could be holes in the diaphragms causing the needles not to lift but you said you check them. If you're choke isn't making it richer maybe you're not getting enough petrol from the tank to the carb bowl. You could check your fuel level with some clear fuel hose connected to the drain on the bowl and open the drain screw and see if the fuel level is correct and if the level is maintained when the engine is running or does it drop

I think it has a carb on it. https://bikez.com/motorcycles/keeway_superlight_2018.php Very hot suggests it's lean. You could try giving it full choke. If it runs better with choke it means it's lean from not enough fuel. When it cuts out you could open the drain screw on the carb bowl and see if there's petrol in the carb bowl. If there's no petrol or very little it could be caused by a blocked vent on the tank as was said, or a blocked fuel filter or faulty fuel cut off tap or faulty float valve in the carb or blocked carb.