Exploring the wiring loom of a Chinese quad / scooter. 

Since Clive lives on the Isle of Man, it would only be appropriate for him to buy a crotch rocket and drive recklessly about the island.

Starter safety switch: I have owned 2 scooters, one decent Japanese ('85 Honda 50cc), and one cheap Chinese (201? ??? 250cc). Both have a sort of interlock relay that is wired to the brake lights. You have to engage the brake to use the electric starter. Both use a belt-type CVT that outputs to a centrifugal clutch which transmits power to the final reduction, and the rear wheel. Adding in a manual clutch is something that is only done for vehicles that have a manual transmission, which is more expense than you will get out of a Chinese import. Keyswitch and killswitch: Shunting the ignition primary coil to ground has been a standard "safe" engine stop procedure for years, decades even. I have a '73 Yamaha DT250 that the keyswitch shunts the ignition primary to ground in the "off/stop" position. The extra killswitch (to be mounted on the handlebars) is a more recent highway-safety standards implementation to stop a downed bike because the manufacturers put the key just wherever they like, and they may get snapped off in a collision. That flattened killswitch is much more likely to fail safe.

I work on Chinese bikes so much. This is soo needed and amazing. Thank you!!!

Other kill switch wire (plug) is for a remote safety switch or tether as the harness is for a youth quad. The 2 spare wires by the stator are the neutral and reverse indicators if equipped. The reason the handle bar switch wires don't match the loom color code is because they're are a dozen suppliers making them and they're generally interchangeable. I rebuild these little quads as a hobby. It's nice that the looms are cheap because they often fail but would likely be less prone to fail if they weren't so cheap. Good video and explains the electrical system well👍

Only you Clive, only you could enjoy working out a loom, the rest of us mere mortals run away sucking our thumbs looking for mummy.

I just wanted to say we're you you at when I needed a video explaining everything on the harness what it does we're each individual connection goes to saves me big nothing like the other videos I give this a 10 star thank you very much

The size of them quads/ATVs are usually kid-sized, hence why everything is so close together, neat kit though, could be useful for building up custom small-engined power toys... :D

Interesting, particularly how the kill switch works. I've encountered petrol hedge trimmers and leaf blowers where a loose connection would prevent the engine from being turned off. Which struck me as odd, because normally you'd expect a loose connection to prevent it from running at all. Now it makes sense, the loose connection was preventing it being able to short out the ignition.

Ah, the Chinese scooter loom. I remember playing/repairing them quite a bit. At that cost, it's just an excellent bundle of bits to bodge bits.

The other "kill switch" plug is probably for a kickstand down switch... on other usage cases you could use it for a low oil sender.

Seriously, how can you live on the Isle of Man and NOT ride a bike!?! :) :)

Now that is quite a good value. I have seen prices exceeding $30 for the CDI alone for a Baha.

Hey that voltage regulator is something you probably haven't seen before. It is a rectifier with a big fat zener circuit to shunt the output and prevent it from boiling the battery. It essentially puts a constant load on the motor. So the idle on the small low torque motors will be fairly consistent. so when there's no use for the alternator's power all of it gets dumped into the regulator module is heat.

These wire looms are heavily based upon Honda designs. Numerous Chinese manufacturers have been copying Honda bikes since the nineties, and have been manufacturing after market replacement parts since long before that. At some point they stopped copying and started doing their own thing. Many parts are still interchangeable with Honda bits. One thing to note, the single round connectors (those that were loosy) are not compatable with Honda bits. Honda uses a 3.6mm connector, and the Chinese use a 4mm connector. Not a big difference, but conecting Japanese to Chinese connectors will result in them always being loose. Honda's wire colors have been standard and since the 1950's. The Chinese sometimes follow Honda's color scheme, sometimes not. Green with a pink stripe (which would be your red/green) goes to the neutral gear switch, right beside the stator on the engine. This neutral gear switch connects the green-pink wire to ground when the gearbox is in neutral, allowing the neutral gear control light in the speedo to light up. Models with a starter motor use the same neutral gear switch to switch ground for the starter solenoid, so you can only use the starter motor when in neutral. The white wire going to the power regulator/rectifier is to charge the battery with. In old models this white wire simply had a chunky diode, and went straight to the positive pole of the battery. The regulator unit adds a voltage regulator to that. The yellow wire is to power the head light, tail light, the light that illuminates the speedometer when head lights are on, and the high beam indicator light. It goes unrectified, these lights work on AC. The oldest models (on 6 volt systems) had no power regulation at all, just juice straight from the stator. Burning out head light bulbs was a regular thing. In the eighties Honda transitioned to putting a big old 30 Watt resistor parallel to the lights, and then quickly moved away from that again. The modern regulator unit has an AC power regulator parallel to the lights. I'm not sure what is inside the regulator. I assume the AC voltage is clipped with a pair of very chunky zener diodes and a resistor. You get some huge voltage spikes from that stator coil when switching the lights on or off. The Honda coils are reasonably well behaved. The Chinese coils are feral and will provide anything from 10 volts AC at idle to up to 50 volts AC at high revs. And the voltage spikes you get when switching the lights on or off will kill your lights if that regulator is loose, or not well grounded. Indicator lights, the neutral light, the claxon and the brake lights run off the battery. The rear and brake light bulb is a single bulb with 2 filaments. A 5 Watt filament for the tail light, running on AC. And a 21 Watt filament for the brake light, running on DC battery power. Both AC and DC going into the same bulb, with a common ground, which is quite interesting. It becomes more interesting when that ground fails and the 2 filaments are now in series between the AC power for the running lights and the DC power from the battery. Trouble shooting that is a very interesting puzzle that teaches, when stuff gets too weird to figure out, it's a missing connection to ground.

It seems the three pin connector hanging loose is for aux or something else and isn’t supposed to hook to anything I guess. Thanks for helping me figure that out, this mini 4 wheeler will start if I jump the solenoid but not through the starter button , I don’t see a mini relay so I guess it will be the cdi box

The 2 connectors that you said was a safety circuit are actually the neutral switch and neutral light and the 2 wires that aren't terminated that went to the coil is for an optional reverse light mainly for ATVs hope this helps

Basket case two speed Italian moped with pedals. Trouble shot for a few days and I finnally stopped and wired up a tail light as that was missing. Then all of a sudden it started up. They ran the coil thru both the tail light and rear brake light so if rhe bulb burnt out it couldn't be ridden until a working bulb was installed at the rear fender. Pure genius on their part, mostly luck on mine

As a vfr owner and Clive enthusiast I'd love it if you could explain how the reg/rec works or, more specifically, fails. The viffer is renowned for it leaving you very helpfully high and dry.

Cheets mate these harness are used on pit bikes / quads all.the see appreciate you going through it real handy

Buying a loom like this makes life easier than trying to build one. For the money it looks good as well. Making a cheap custom, I bought a Honda loom, on a Yamaha frame and engine, with Kawasaki lights, tank and a few cuatom parts. So much fun. Sold it when road legal. New owner crahsed it. Life........

i remember when this guy was at 400k. crazy that hes almost at a million

The Starting safety connector, one is probably a transmission Neutral indicator, or lock out for starting unless it is in Neutral.

Your missing the brakelight switch which doubles as a start/safety switch, on automatic motorcycles like quads,trikes, scooters which are always "in gear" you always have engage the brakes te start the engine so you wont suddenly run off. Scooters may also have a safety switch on the side stand, the stand has to be up before yoou can start the engine so you dont accidently take of with your sidestand sticking out, ouch.

The spare cutout usually goes to the kickstand so the engine won't start if the kickstand is down

The extra safety leads are for inhibiting the bike starting with the stand still down .

To start it you need to depress one of the brakes to engage the starter. On scooter's it grounds the starter solenoid.

The same loom is probably used on scooters, ride on lawn mowers etc, so will have kill switch connections for all of the possibility's. Side stand down, fallen over tilt switch, weight on seat, grass box not fitted etc.

The chinese discovered that slices in a conduit are much cheaper than in a junction box. I also dunt trust those crimps making a good connection.

Spark plug's on top of the engine - other stuff (magneto etc) is down the bottom.

I wonder if the regulator is simply selecting "charge" or "float" windings.

Water always, always finds a way in. The key is to give it a way out.

Neutral or clutch to start perhaps. Neutral or stand up enables ignition on my bike

Sometimes you have a green light on the dash to show you when you are in neutral.

What is the benefit of having 3 cathodes on a spark plug? How many sparks does it make and where?

I'm thinking the kill switch circuit shunts to ground so that one can't push start the quad to steal it?

You didn't name all the ends. What's the long 2 wires on the handlebar end. Longest 2 wires with connectors

I just spent many hours troubleshooting the engine management in a Chinese manufactured ATV using an 1100cc Chery motor. Talk about horrific - no documentation, waterproof connectors that weren't waterproof, everything (including the ECU) had some level of corrosion, relays could be turned on and off with a squeeze... simply catastrophic. I did get that POS to run finally. Would not recommend.

Is that 200V a.c.?

The extra kill switch wires are for a alarm and remote kill button for kids

how does a 233cc motor work with 2 cylinders and 2 spark plugs both pistons top out at same time do you use 2 coils thanks

"Is there a catch?" Yes it's shit and will pack up in a month or two. I've worked on a couple of Chinese bikes and this stuff is hopelessly unreliable.

I'm working with Mercury outboard motors from the mid 90s where the manufacturer seemed to change the part numbers of the Stator/Trigger/Switchboxes at random. Constant change/improvement leading to constant chaos in the repair of these motors. And no particular numbering system to identify one expensive little black plastic box from another. No consistent compatibility. Frequent parts failure. Would it be interesting to bring your expertise to bear?

17:15 side stand switch 🙂

ghost in the machine.. i got a 2nd hand 2021 tiking 4 seater 200cc kart the other day. it was a crank no start, owner said the shop replaced the cdi a few weeks earlier and a few days after that it died. and he decided to sell it. for a 2021 it was mistreated i could tell every single bolt and nut was loose some hand tight loose.. the breather hose from box to carb gone the electric box cover gone and it was pouring down rain when i bought it..i tested the stator, and all was good but knowing what the kart been through i replaced it anyway. still no spark then i decided to put a new CDI in it and i had spark. then put plug in tried to crank nothing pulled plug no spark, tested the CDI it was blown now also. when i took the voltage Regulator off the mount i noticed the bottom was cracked bad. so im not sure where to go with it. but i noticed some weird stuff if i wiggle the key switch the dash lights and speedo meter flicker. also i went to measure the holes for a new tail/brake light with my digital gauge and it was going bonkers when i put it up near the electric box area something is shorting somewhere just not sure where to look..i have checked all grounds all are good now. i do have a new ignition/key switch coming and new CDI..

16mins in is a fine example where a digital meter is a poor device to demonstrate with. Numbers flashing all over the place. By watching it carefully it is possible to follow what is happening but it takes a bit of effort. An analogue meter will be steady and changes of switch state obvious. Horses for courses I know. Analogue is unbeatable in some applications, digital when you need to know the voltage of your pp3 battery down to 0.001v.

To be fair, you can get a chinese quad for a tenth of the 'stealership' ones in a country that likes to jack up prices of imports. Yes, it is half the physical size and probably not 4wd. Yes, I belive most countries do not allow them on public roads. Yes, the drive chain will snap like boiled spaghetti if a overly grown up kid tries to give it all it got. Yes, the engine might not start without working on spark plug or a full on carb clean after a long cold winter. Will any and all parts wear out faster? Undoubtedly. Can you have fun on a small quad even if it is rwd? Oh yes. Can you find a venue where the law is not looking? Most likely. Can you go to the nearest motor cycle shop with the snapped chain and ask for a stronger replacement? I sure did, and I sure got. Is it difficult to clean or change a spark plug, or clean out the carburator? Not if you are able to search for a few how to's on youtube and realize that maybe five videos telling you to do it one way and one having a very easy fix suggests that there may be reasons why most don't use the easy fix. Can you order a complete quad out of spare parts to fix yours? At least in the case of mine as it turns out. Bottom line, you get what you pay for. I got a cheap-ass quad that is fun to tear around on. I have also spilled figurative and literal life blood on it as I have taken it apart and replaced parts. Basically, do not under any circumstance buy one of these if you want something that will just start and run. Get something with a honda engine.

Funny thing is, you can disconnect a key module, run engine and go away.... without key.. .

Point at any of those parts and they would cost $25 each if made in USA

The engine kill switch plug that isn't plugged in to anything probably plugs in to a proximity or microswitch in the seat mounting that cuts the engine when there's nobody sitting on it.

get Icebear rockets for the beard club

Put that on a scooter is like saying "id like to be dead really painfully please"

At uni I was taught never to solder or crimp a loom as the change in stiffness can cause the copper next to the joint to work harden due to vibration. How much of a problem it is in the real world I don't know.

sounds like something ud buy after u steal a bike

The trouble I've had with "waterproof" switches on bikes is that once the water gets in, it never dries out. 😁 I'd rather have an "open" one with the contacts slathered in vaseline, for most purposes.

This has to be your single most niche teardown.

Start inhibit is often wired to a switch on the side stand.

The 2 spare wires at the stator are probably for a neutral light switch. It's very common to kill the engine ignition, simply by shorting out the CDI supply coil. Lots of small engines use this system, from cheap quads, bikes and even petrol garden power equipment.

It's disgusting and crude...I love it

Everything corrodes on quad after time, even the rider.

The two safety wires with spade terminals are for the hand brake, you have to hold the brake on to start.

we'll start with the key switch..... ....Hi, I'm the lock picking lawyer Missed crossover opportunity

This is why I love Clive random tear downs of random bits.

The green and black wires hanging loose about the stator is likely for neutral indication and possibly oilpressure or temperature warning/fan.

i put one of thease looms in one of my motorbikes i built it seems to work just fine. its a perfect cheap replacment for a old honda cub. Lights are run striaght from the alternator/Stator so you have A/C lights so the lights are very dim on tick over but get brighter when you ref the engine. The safty curit is for the side stand if the side stand is down the engine wont start. i think thats everything Get a motorbike

Cheers man your helpful diagram saved me!!it's 23rd Dec and my son's new 50cc 4 stroke has been treated to a new wiring loom I was stuck but just got dug out of a hole I dig for myself my son is going to be happy on Christmas thanks to this helpful guide cheers brilliant...

I got a 50cc chinese quad and this are my findings for the connectors you were unsure about; - Dash ? labelled connector is for brake light, - the 2 wires at stator are for neutral on 3 speed models (imo) - the safety switch with the solid connector is for the "fall off bike" feature, that will shut down the quad in case of a fall - the other safety is connected to the brake switch on automatic model to ensure the bike doesnt start to rollout on it's own on chocke start being an automatic Keep it up, great video!

The 'kill' switch has traditionally shorted the ht on small engines in this manner since year one. Edit it is a low energy (in comparison) solution.

hey in my quad it haves the same kill swich but it was broken only 1 lead was connected to +200v and i touched it and it shocked me hard

In my experience the regulators are a glorified zenner. Also capacitive discharge spark circuits are used to accurately control the energy of the spark. IE to reduce the energy to the minimum needed to reliably ignite which then extends the life of the spark plug. In boiler controls the circuits used to deliver a minimum of 6mJ but in reality were more like 7.5mJ to take into account component tolerances. Or that's the way I used to design them anyway.

They're not waterproof so that if you're not trying to keep water out you can't keep it in either 😉

the joys of the chinese wiring looms......so beautifully made ...... keeps us auto sparkies in business though

@bigCLIVEdotcom the rectifier is just a few diodes, to rectify the AC to DC current for the battery. it's not complicated in there. it just dumps the bottom half of the sine waves to ground, and or to heat radiator, that generated by each of the coils.

On my chinese scooter you need to have the side stand up and the break on in order to start it, so that is what some of those extra connectors are for. You are right about nothing being waterproof. The horn on mine packed up when it was about 6 months old. I investigated and it was simply a non-waterproof component with exposed wiring tucked behind the plastic faring. Basically if you ride in the rain you need to make sure you park it somewhere dry and windy afterwards. I think these bikes are designed for occasional use in nice weather. But as the entire scooter cost £1K brand new, on the road price, they obviously need to cut a few corners.

That extra kill switch is most likely used for a kickstand safety switch. Kills the engine if kickstand is down

The first bike I ever had was a super cheap Chinese 49cc moped/scooter called a Taotao. It was $800 new, I bought it for $300. The engine was basically a Chinese clone of a Honda GY50, which was nice because it allowed me to buy better quality parts designed for that engine (things like carburetor, clutch parts, etc). I only got it to see if I was interested in riding on 2 wheels (I was). The wiring loom on it looked basically exactly like this, although I'd imagine the wiring between the handle bar connectors and everything else was longer. Nothing was water proof, but I still rode it in the rain regularly. Rode it for a year, sold it for $400 when I bought a real bike.

The spur off the lighting circuit is probably the speedo backlight, the safety spur may well be to stop the motor being started in gear

AMAZING value for that price! I'm looking forward to the depotting attempts.

at 12:59, you sound like you mean the secondary (external) coil fires on an expanding magnetic flux field, current starting to flow. traditional ignitions fire on collapsing fields as it takes time (dwell) for coil saturation. rough gauge would be primary windings will be low resistance, only a couple ohms. i spent some time researching LC circuits, because of an unusual type of ignition called "energy transfer" where the points short the output of the stator coil to ground until they open, leaving the HT primary windings as the only available path, low resistance, they saturate very quickly, firing on an expanding field with points opening. www.motorcycleproject.com/text/ignitiontech.html (discusses multiple styles of ignition) as my shop teacher said about saturation, "it's quicker to empty a bucket then to fill it"

The CDI does have a very simple ingenious timing control Clive, the higher the engine speed the quicker the rate of voltage rise at the inductive sensor meaning the trigger threshhold of the Thyrister will be reached earlier in deg. rotation of the crank shaft. A lot of the magic behind these deceptively simple harnesses can be explained by getting hold of an earlier Honda workshop manual, something like a CT110 series or the single cylinder trail bikes. If the lighting system has been copied correctly it's an AC/DC system, where the head and tail light operate straight from the magneto AC coil, the brake lamp and battery charging is via the DC section and the regulator. This was a deliberate system by Honda to the make the bikes unstoppable, no battery or a failed regulator, no problem providing the coil is not burnt you still have lights to see. Same logic for the CDI, completely independent of the battery DC system, if you can kick or push start the engine it will run. Royal Enfield still use open connectors like those to this day.

do a car wiring loom, go on

You may find the 2 wires in the stator harness and the kill connector are linked to the side stand switch, which cuts the engine if the stand is down and engine running in gear (not neutral)

The CDI and ignition coil could be on the handlebar side of the loom so that they can be mounted higher up on the chassis to reduce the likelihood of getting wet. The rest of the loom probably still can't handle water anyway due to the low price, so this design may have been copied from a more expensive loom.

@bigclivedotcom i've been buying chinese happytime 49/66 cc engine kits for bicycles for the last.....20 years? my current death trap is built on a 24 inch frame with hella modded engine setup because they are made to fit on a 26 inch frame, they are FUN, you should get 1, $150 and you can feel like you're going to die for only $150 usd

Very nice. I should look for something similar for my homemade electric bike. Also you should get an electric bike conversion kit if you haven't yet. those are fun to both build and ride, and on the isle of Man they would probably be pretty useful

Hey China, could you toss together a complete wiring loom for a 2006 GM Chevy Malibu? (I'd be willing to pay TWICE what Clive paid for the above loom!)

Its ironic... lol but life is funny this way I guess. I saw this video.. I was interested in one of those electric scooters thinking this was a wiring thing for that, as I was looking to buy a busted Scooter and make it a project. After realizing that this was for a gas powered scooter... I left it alone midway. Well.. I was in need of a utility trailer.. a small one and I found one with a scooter on it and it was a package deal. It was such a good price I bought it. Well.. the scooter doesn't work and its one of those GY6 Chinese clones with 1E40QMB Engine (its cute how I care about which engine I'm using). I'm learning that they do things in such a way that they cut corners everywhere. Well.. I want to have a scooter and now this is my project. Now I find myself BACK to this vidoe.. and after a day of doing research... this video makes so much sense now! Thank you so much for the effort and care you put in explaining and helping me educate myself on what does what and where I need to test and check. Plus your voice is not bad to listen to.. no homo.. but some of these videos ruin themselves because of the audio.

Lucas did have a fairly standard wire colouring system. I guess the complexity of modern automotive electrical systems outgrew it.

The stuff you can get on fleabay!! Mates 10 year old Alienware laptop still a perfectly servicable computer that only needed a new keyboard and an SSD. All sourced from Evilbay :)

Those kill switch connections are likely a parent cut-off switch with ribbon type setup mounted to the rear of the quad so a parent can walk behind and cut the engine if required, these China quads also have an optional remote start stop alarm system fitted which accounts for the second spare kill connection 👍🏻

The cdi box's go bad from the silicone braking down and cracking. And its the e85 they put in the fuel. When it sits for any length of time it turns to gel and plugs up the carb. It basically kills them. If you run racing fuel or fuel with no e85. Won't gum up just sitting. Just fyi my guy. Hope it helps.

I'm curious to see if you can hijack an electric scooter type setup into running a brushless faster 🛴

I would think the extra kill goes to the brakes, as this is a kids 4 wheeler. Usually you have to have the brakes on to start them like a lawn tractor.

I like the way you explain things the suttal humor/sarcasm and the comment in the discription of being naughty opps i didn't design that did I.Guess we can all get a little over zealous.But that always makes it fun learningAnd exploring on our own.Makes more sense when you deduce and make logiic or not of something.You tend not to forget when you make it fun and interesting.Cant wait to see the inside of the regulator/Rectifier.Its nice to know then how to build stuff from scratch.Then one day it clicks and youved solved all the wirds problems.But i do still always know whats wrong?Somethings not right.Must uf made an expensive noise when it failed.Do you hear something?Nah turn up the radio.Its Only fun if it's fast black and loud.ok what's next?🤔

Your way of communicating the jobs of each component is fascinating UOU should teach. ME. YOU SHOULD TEACH ME FIRST. AND IM AN ELECTRICIAN unfortunately that makes no difference where plugs are located

1: The safety switch is probably for the side stand. I don't really know what type of bike this is for, but on a normal motorbike you can start the engine while the side stand is extended (one switch), but as soon as you put it in gear (second switch) with the stand extended, the engine is killed. 2: The ignition box should have some kind of logic to delay ignition while in low RPM and advance it for higher RPM. So the signal coil doesn't really initiate the ignition, it just serves as an index on where the crank shaft is at the moment. Forget these animations where the piston sucks in air and the spark plug fires exactly when the piston is all the way up. It takes time for the flame front to travel throughout all the volume of the cylinder, if you fired the spark plug at the uppermost point it would combust only after the piston has gone down again and blow out the exhaust. At higher revs, the spark plug fires LONG before the piston reaches the top. An engine that fired the spark plug always at the same time would have piss-poor performance everywhere except at one point where the ignition advance fits the revs. 3: Say "au fait" once more and I'll come over to the Isle of Man and beat you up.

I think the last spark plug I bought was twice this price...

Only the Chinese could make Lucas Electrics look good. Should we call this "Rucas Erectlics" or "The Plince of Darkness"?

I bought a cheap Chinese 125 in 2016 and it was faulty on arrival. Turned out the CDI at fault. Rest of the machine was okay-ish. Though they need more maintenance than other bikes. I've SORN'd mine as it needs a lot of work.

Ahh the joys of working on cheap Chinese bikes (ATVs, Scooters, Minibikes and Go-carts). After about 3 years of sitting out in the rain and sun, many of the original connectors become brittle and crumble. When troubleshooting an electrical problem, it is easier and cheaper to replace the entire electrical system. These Quads are considered disposable as in a couple years of use the child is ready to step up to a larger machine. I am rebuilding a Quad for a neighbor kid and amazingly all the parts for this bike are ridiculously cheap. I too have acquired the same harness and puzzled over the connections. Maybe someone could make use of these inexpensive components for other projects?

Cheap Chinese crotch rocket? I didn't think any Chinese motorcycles were imported to the US or UK? Other types of crotch rockets, different story.