WD-40

It'll run ok off the battery for a while then as the battery goes flat the problems show up. I'm just going on what you've said. You said there is resistance between yellow and green. That's a short between the stator and ground. Try starting the bike and measure the voltage at the battery. If it's 13V at idle and rises to around 15V when you rev it to 6000RPM the charging system is working

Yeah you did that test correctly if you unplugged the connector from the Reg/Rec. The resistances means the stator is touching ground which it shouldn't. It should be separated from ground by the insulation that's painted over it. What happens is if the stator gets too hot it burns the insulation coating and that causes the stator to touch ground and that's a short circuit.

Yeah if there's resistance between yellow and green with the connector unplugged from the Reg/Rec, that would show that the stator is touching ground which it shouldn't. Try taking the cover off the engine where the stator is and have a look at the stator. If one of the stator windings is burned it needs to be replaced.

You could bring a spare spark plug with you and when cuts out and won't restart disconnect a spark plug lead and plug in the spare spark plug, ground it against the engine and hit the starter button and check if you've got spark or not. Be careful not to shock yourself.

With the connector at the Reg/Rec unplugged yellow to green should all be OL when checking resistance. There should be no connection between yellow and green. Yellow to yellow should show resistance. The spec for what the resistance should be is in your manual. 13V on the battery at idle is good. If it's 13V rising to around 15V when you rev it to 6000RPM it means the charging system is working. If you don't know how the charging system works and the other video is too long have a look at this one.

it's definitely dead

I'd guess the end of the exhaust must have rusted and the rust has swelled up and jammed the exhaust into place. You could try scraping away any rust that's built up around the exhaust where it joins to the engine. That might free it up enough that you can get a bit of movement on it and wiggle it out. But heat is probably the way to get it out. I had a friend who had the same problem on a cbr250rr. He was trying to replace a rusted exhaust. The header was stuck in the engine like yours. He was getting more and more frustrated so he kicked the exhaust and it fell out so he thought great it's out but on closer inspection all that had happened was he had snapped the exhaust into two pieces and the rusted piece was still stuck in the engine

Here's my understanding of it. It's a bit of a long winded explanation, might sound hard but it's an easy enough to do. You're basically measuring the DC voltage across the battery when the bike is running. Then measuring the DC voltage out of the Reg/Rec. Then measuring the AC voltage into the Reg/Rec. Then measuring for high resistance in the stator. Then checking if the stator is short to ground. You can have a fault in the wiring, the Reg/Rec, the stator or both the Reg/Rec and the stator. To accurately test the Reg/Rec the AC voltage going into it has to be good so the alternator has to be working correctly, so the stator in the alternator has to be good. You can't diagnose the Reg/Rec until the AC voltage going into it is good. The procedure is. Start the bike. Measure the voltage across the battery. You should see around 13V DC at idle rising to around 15V when you rev the engine. That would show that the charging system is working properly. If you see less than that or more than that you have a problem with the charging system. If you have a problem next measure the voltage at the Reg/Rec. There's usually five wires at the Reg/Rec. Three wires will be the same colour, they're the AC wires coming from the stator in the alternator, going to the Reg/Rec. They're the input wires going into the Reg/Rec. AC goes into the Reg/Rec and DC comes out to charge the battery and power the rest of the bike. So the other two wires at the Reg/Rec are the DC output going from the Reg/Rec to the battery. One wire which is usually red goes to battery positive. The other wire which is usually green goes to battery negative. With your meter still on DC measure the voltage across the red and the green wires. That will tell you the DC output that is coming out of the Reg/Rec. You should see what you saw across the battery. If you see something different to what you saw across the battery it would mean there's a wiring problem between the Reg/Rec and the battery which is unlikely. Most likely you will see the same voltage as was on the battery. Good would be around 13V rising to around 15V when you rev the engine. If the DC voltage coming out of the Reg/Rec is too low. Switch your meter to AC and measure the AC voltage on the three wires that are the same colour going into the Reg/Rec. You have to measure every pair of combinations of the three wires because they're all connected. The voltages across all connection pairs should be roughly the same. About 20V AC at idle rising to about 70V AC at 6000RPM but those numbers are just a guess. All bikes are different so check your manual for the exact number. If the voltage is low across any connection pairs you probably have a damaged stator winding and you will need a new stator. You can confirm the stator is damaged by turning the bike off and doing a resistance test between the connection pairs. Set your meter to resistance and measure the resistance of every combination of the three wires. Your manual will give you the spec of what the resistance should be. If one pair of connections is higher resistance than the others it shows that one of the phases of the stator is burned and you need a new stator. If you take the engine cover off to check the stator you will probably see a burned or discoloured area on the stator. You should also test if the stator is short to ground. It could look ok with no signs of burning but still be short to ground. That happens if the insulation coating on the stator has failed and the stator is touching the rest of the bike which it shouldn't do. It should be isolated from the rest of the bike. You test for a short to ground by measuring the resistance between each of the three wires that are the same colour and the green wire which is ground. It should show infinite resistance on the meter which shows that there is no connection between the stator and ground. Usually the meter shows OL or something like that. If a resistance reading comes up on the meter it shows there is a short to ground and you need a new stator. The voltage tests with the bike running are probably the best to do because sometimes electrical faults only show up with the bike running when things get hot and expand. If you find that the stator is faulty replace it and do the tests again. That will confirm whether the Reg/Rec is faulty or not. If it is faulty and you don't replace it it could burn out your new stator and you're back to square one so make sure you test it after you install the new stator. This guy has a good video on testing the charging system. He starts taking measurements at around 20 minute You should check your workshop manual too for the proper procedure and the spec on what values to expect.

Sounds like the cam chain tensioner on the new engine is loose and or it's missing the copper sealing washer to stop oil coming out. That's not good because the slack cam chain might have slipped on the cam shaft. That can cause the valves to hit the pistons. If the seller said it was a good running engine you could probably ask for your money back

Haven't installed one myself but it would make a great project for learning more about motorbike electrics. And if you ever sell the bike and move onto another bike you could always remove it and install it on your next bike or you could sell it and recoup some of your money so you can't really lose. I think Koso is a popular brand. You should find the info you need on their website https://kosonorthamerica.com/ With that info and the wiring diagram in your workshop manual you could figure out all the wiring connections before you commit to buying anything

The ball on the end of the foot peg is what scrapes the ground when you lean over in a corner. They bolt on so I think the idea is that as they wear away you're supposed to replace them with a new one and that stops you wearing away the foot pegs The idea is that it lifts the peg before it digs into the ground and throws you down the road Makes sense. I think that's why the foot pegs fold back too.

The ball on the end of the foot peg is what scrapes the ground when you lean over in a corner. They bolt on so I think the idea is that as they wear away you're supposed to replace them with a new one and that stops you wearing away the foot pegs

I'd check the connector and wiring going to the right handlebar for an open. It could also be corrosion in the switches but the front brake light switch is usually separate from the other switches and it's not working either. It's possible they all have corrosion but it's more likely there's an open in the wiring going to the right handlebar

Yeah make sure all the bolts are out along the whole exhaust. Give the area where it joins to the engine a spray with some oil if you've got it and then increase your swearing by 200% and it should come off

I was drilling a hole in a piece of metal. The metal was clamped in a vice on a table. I was holding the drill in one hand and I had the other hand leaned on the table. You can probably guess what happened next....Snap, the drill bit broke and the drill slipped off the metal and I drilled straight into my thumb that was on the table What a plonker

Sounds like you're getting used to riding in windy conditions now. I think everyone who started on a 125 probably went through those same experiences. I think if you're nervous it makes the effect of the wind worse because when you're nervous you tend to tense up your upper body. You grip onto the handlebars tighter and your arms and shoulders get tighter, you become more rigid and that means when the wind blows against your body it causes you to steer the handlebars and that make the bike move around the road even more. If you grip the tank tighter with your legs and relax your upper body when the wind blows it will blow your upper body around but the bike will stay going in a straight line because your not turning the handlebars. That's what works for me anyway.

What I mean is you should plug in the white plastic connector that's on the new ignition into the connector on the bike and make sure it starts before you mount it.

Where did they cut the wires? Do you still have the original block connector where the ignition plugs into the bike's loom? If you still have it you should be able to just unplug the old ignition connector and plug in your new ignition and you can test if everything works before you go to the trouble of fitting it. If they cut off the block connector you'll have to get the male half of the new connector and join that to the bike's loom

I'm not sure if this is true on fuel injected bikes but on a carb bike if there's water in the petrol and you leave the bike parked for a while the water settles out of the petrol and collects in the bottom of the carb bowl and at the bottom of the tank so the first time you try to start the bike after leaving it parked for a while it'll have a hard time starting because it's trying to start on a high percentage of water. After you get it started the first time it starts more normally because the water is now mixed around with the petrol, then if you leave it parked for a while and it'll have trouble starting again. As I said though I'm not sure if that would happen on a fuel injected bike but it might be worth checking if there's water in your tank. It usually gets in because the drain pipe in the tank under the filler cap is blocked so rain water goes into the tank instead of draining away.

As a quick test you could take the spark plugs out and dribble a small bit of petrol directly into the cylinders. Then try to start it. Making sure you have a good battery that's charged and your air filter isn't blocked. It should start and run for a few seconds on the petrol you just dribbled in. If it does start then that confirms the spark and timing are good and it would point to a fuel problem.

What a beauty

If everything shuts off when you try to start it I've found that's often because of a bad connection on one of the main current carrying wires. Most often it's a loose battery connection or a bad ground connection to the frame or engine, it could also be a bad connection on the main fuse but I haven't personally seen that.