WD-40

Yeah maybe there's a few different version of it. I just went by that Suzuki manual

If he's a fairly new rider and he's on a brand new 0 miles bike I don't think he should be doing clutchless shifting.

If you look in that manual it shows no battery and no reg/rec for a DR125. It's just AC from the stator going to the cdi. If he has a reg/rec and a battery it must not be a DR125 it must be a SP125G

Seems like you might have a weak spark or you're losing spark. Sometimes you can have spark at atmospheric pressure by not under compression. You can get one of these spark testers. That will tell you how strong your spark is. If you get one make sure it has the stud type connector on the end. The other ones only fit car spark plugs. https://www.ebay.co.uk/itm/Adj-Ignition-Spark-Plug-Tester-Inline-H-T-Test-Lead-Diagnose-Car-Engine-4121-A32/363010081019?hash=item54851640fb:g:M2oAAOSwlsde1TwY

Looks like a new air filter to me

What does the spark plug look like after you try to start it? Is it wet or dry

I could tell you how to turn it on without the key if you want to try to start it

If you look on Fowlers parts website you will find a picture of your starter motor fowlersparts.co.uk

There's a Haynes for a cg125 http://die-kleinkraftrad-ig.de/wissensdatenbank/reparaturanleitungcg125.pdf and a colour wiring diagram https://dc611.4shared.com/download/LQ9VNsokce/Honda_CG125_CG_125_Electrical_.jpg?dsid=KcO7Iw3I.a0dca58d666610171754783f594698d0&sbsr=d41bc81afd0a6a4e851cd8e7c7f87538a48&bip=ODAuMTExLjYxLjMy&lgfp=40

You'll have to do the usual checks. Have you got spark? Have you got compression? Have you got fuel? Hopefully it's something simple.

A few important things to check, oil level, is there oil in the sight glass? Is the chain dry or slack? Tyre pressure, is it low or is there anything stuck in the tyre? Are the critical bolts tight, like brake caliper and axle bolts? Are your brake lights coming on and going off properly? Is the headlight working? That's what I check before I set off in the morning. Might sound like a lot but it's not, only takes a minute while the bike is warming up Have a read through your owners manual https://www.yamaha-motor.co.th/docs/owner-manual/commuter/en/mt-03-en.pdf?Status=Master&sfvrsn=ba911a2f_4 If you want more info have a read of the workshop manual https://www.moto4.ru/downloads/yamaha-mt-03-service-manual.pdf

If you can get the front wheel up in the air, grab the bottom of the forks and rock them back and forth. You're trying to feel for any in and out movement. Or any notchy rough feeling spots as you turn the handlebars. In my experience if the steering bearing is loose you're better off replacing it. I have tried tightening and re greasing them in the past and they were better for a few thousand miles but they went loose again and had to be replaced. Other things that could cause a click sound in the front would be brake pads moving or possibly front wheel bearing. How many miles are on the bike?

Yeah they might try to weasel out of it. But if you followed their maintenance schedule and changed the oil when they told you to I don't see how they could claim negligence.

If you went for a weekend away you'd have to bring a litre or two with you The R1 had a lot of problems too. https://www.bikebandit.com/blog/how-yamaha-s-massive-r1-recall-is-an-opportunity-in-disguise I think BMW have had problems too. Yeah I was thinking the same! Although a mate had the CBR and it never used oil Maybe they sorted the problem on later ones? Or he just got lucky. You really have to do your research before you buy anything nowadays. There was a thread on here about the new Honda Rebel. They wanted the valve clearance checked at 600km and every 6000km after that. What??? Something not right there

I heard the CBR1000 burned some ridiculous amount of oil and Honda said it was normal so it does happen Yeah they claimed 1 litre of oil per 1000 miles was OK If you went for a weekend away you'd have to bring a litre or two with you The R1 had a lot of problems too. https://www.bikebandit.com/blog/how-yamaha-s-massive-r1-recall-is-an-opportunity-in-disguise I think BMW have had problems too.

Yeah I saw one with 4200 miles on the clock and it had blown up! that's ludicrous, why would they sell it with an engine that uses so much oil surely triumph should have ironed that out in testing.....and I thought that british bikes were just mean to leak the oil from various gaskets/seals rather than eat it I heard the CBR1000 burned some ridiculous amount of oil and Honda said it was normal so it does happen

Did a quick google search there and you're right. There's lots of examples of engine blowing up. Doesn't make for good reading Yeah I saw one with 4200 miles on the clock and it had blown up! That's shocking. You'd think they would have to give a refund if it only lasted 4200 miles.

Did a quick google search there and you're right. There's lots of examples of engine blowing up. Doesn't make for good reading

Could well be, maybe a top end rebuild on the cards eh Don't know. Guess you'd have to open it up and have a look at it. If it was a valve problem would it still idle like it was in the video? Don't think so. Could it be a cam chain tensioner failure and the noise is a mad loose cam chain? That's just a wild guess

I agree with Stu doesn't sound good. Has a bit of a metal on metal sound. The phone could be picking up the sound coming from the can

Could be an exhaust leak where the exhaust joins the engine.

https://www.wd40.com/myths-legends-fun-facts/

That's a nice setup

Is all oil not a water dispersent since oil and water don't mix?