Tapping noise coming from bottom end of engine

[Dragon_uk]

First of all would like to say hi as this is my first post.

Problem happened on my wife's dad PCX125 2014 with about 13k miles on the clock.
Usual clutch bearing noise started to be noticeable just after 10k service so thought will leave it till 15k belt and brollers change. But in the end it got so bad I didn't want to wait another 2k.
Ordered belt rollers oil both clutch bearings and day it got delivered the other noise started.
So I've stripped bike down and done valve adjustment but it was near perfect so, intake had right gap and exhaust was slightly bigger so I've got it down to 0.009”.
Obviously bearings had to go in the freezer and clutch on radiator over night so only got bike back togeter last night.
Drives perfect, pulls nicely no clutch noise any more but...
Engine noise is still there.
I've checked for any sounds of blown gasket, checked exhaust, spark plug was perfect, oil drained and no metal in it, even changed final gear oil that also was fine.
Tapping isn't metalic sound so its not tappers or valves.
It shouldn't be chain tensioner as noise is adequate to rpm of the engine.
Will try to record a video and add it today.
Please advice and help before engine goes.

Many thanks

[easyrider]

A sound recording is essential, however you said you replaced the rollers in the variator. You say( I think )that you did not have that noise prior to your work. I would once again check the rollers for proper installation and for any deviations in there.

[homie]

Congratulations on your mechanical skills. It's good to see this level of talent in new membership. As you pursue this issue perhaps someone will suggest something that solves or opens new possibilities for you. Of course I will think about this too.

Please join the short list of PCX whisperers who have shown similar abilities and special skills.

[Mel46]

Do you get this sound when it is on as well as on the road? If it is obvious on the center stand with the engine idling then I would say the problem is in the engine. However, if it starts only as you accelerate then it might be the belt slapping. In that case check the tension on the belt or replace the belt.

[Dragon_uk]

Thanks for so many of you guys getting involved already.
Noise started few days before I've done any work.
Rollers are 100% assembled properly.
New belt fitted and had it running with everything on and cover off so no belt slapping 100%.
At tge moment got bike in normal every day use and will probably just wait for it to get worse or die so then will know exactly what was the problem lol.
But now seriously, I will try to record video tomorrow amd hopefully I/we can get it sorted before poor thing dies.
How do I join the whisperers? Would love to as I'm a car mechanic by school and at the moment got in my garage 2014 pcx125, 2016 pcx125, 2014 sh125, 2007 50cc chinese but playing with it a lot 100ccbbk 150cc carb etc.... 1986 bmw e30 4.4V8 and every possible conversion or upgrade done to it.

[easyrider]

I have taken that approach many times myself. Sometimes , however waiting can compound or destroy other parts as it can sometimes have the domino effect.

[stevecbr]

Its nothing simple like exhaust starting to blow?
I'm not sure where the water pump is on these, could it be the bearings there?

[homie]

How does it sound on the stand?

[Dragon_uk]

Easyrider- the only upside would be that my in law could get 2nd hand engine for £300 and I would have his dead one to mess with it and build 190cc bbk

Stevecbr- 100% not the exhaust as when I block it pff completely it just kills the engine within few seconds and no other sounds coming anywhere along whole exhaust system ( also checked two 10mm bolts on the engine side)
Water pump is on the right hand side between rocker cover and radiator roughly but will give it a second look.
Good suggestion thanks.

Homie- on the stand it sounds like it had air leak or bit of soft wood tapping inside. Frequency of that tapping sound is matching engine revs.

[homie]

Some GY6 troubleshoot tips for engine noises



Hope it's not this bad

[relic]

Again I'm not being much help but if you like tinkering with engines and a spare lined up, run the one you have hard and see what develops. You're wife's dad might disown you for that kind of advice but you are running out of solutions here besides a complete tear down.
Sounds like you know where to look and have covered the bases.
Putting the bearings in the freezer sure makes installation easier

[Dragon_uk]

Ok I've finally got chance to video the problem.
I've done two bikes only to make sure you can hear difference as wasn't too sure how will it sound when recorded by phone.
Hopefully this will give you the idea of what noise I was trying to describe

https://www.youtube.com/watch?v=kT5OAgEBNvs

Sorry for parrots making noise in the background (told them to shut up for couple of minutes but they never listen)

[homie]

Thanks for video... I don't hear any birds, very difficult to hear the sound you describe as a wood block thumping. I used full bass and treble from computer not phone to listen. From this audio one might suspect your header is not seated properly or exhaust is responsible for the different engine noise. Pretty much the sound seems more air than any metal for me. But I'm sure you've checked out your exhaust installation already.

[Dragon_uk]

It has all started before any work was done. And since then I've adjusted valves so rocker cover i 100% back on properly and tight.
I've checked exhaust head to toes and looks good, two 10mm nuts are tight too. And when I block the pipe with something engine stals and not even a smallest tiniest bit of blow can be heard so no gas leakage.

[you you]

Thanks for video... I don't hear any birds, very difficult to hear the sound you describe as a wood block thumping. I used full bass and treble from computer not phone to listen. From this audio one might suspect your header is not seated properly or exhaust is responsible for the different engine noise. Pretty much the sound seems more air than any metal for me. But I'm sure you've checked out your exhaust installation already.

I can hear it. I'd be worried, and I don't normally say that. Has it been run low on oil recently?

[Dragon_uk]

You you miserable tw@t lol
No it hasn't been run low unless 50-80ml top up is considered to be low.
Would your opinion be to strip it down completely before it does too much damage?
No metal in oil what so ever and that been changed this week also when was doing belt and other staff

in my opinion it doesn't matter but when moved radiator out of my way so I can see sign on fan I've noticed that magneto is covered in rust. Is this normal? (don't think so but would rather ask)

[Alibally]

Sounds quite bad. It can help pinpoint it with a wee trick. Get a long thin screwdriver, put the handle to your ear and the end of the blade onto the engine. Move the screwdriver about till the noise sounds worse. It works best with a hard plastic handle not a rubbery one. It works as a rudimentary stethoscope. Obviously don't get too close with to face to moving / hot parts.

[DAB]

How many miles has it been run in this condition?
Which oil 10-30? if so try some 20-50 and see if it is any quieter.

[DAB]

I've noticed that magneto is covered in rust. Is this normal? (don't think so but would rather ask)

Mine was like this, so normal I guess.

[Alibally]

I cant see thicker oil making any difference. It's only going to mask the problem.