Agility 16+ noise identification

[Prostidude]

Hello, I’ve bought this scooter with 9k km on tacho and I am trying to find source of weird sound-symptoms below Non-metallic rattling sound above 50% of the throttle Only under load Sound is similar to spark knock, doesn’t change with high/low octane fuel-stock cdi from factory Seems to be coming from top end of the engine Valve clearances are tight 0.1mm on intake and loose 0.1mm on exhaust No power loss or any issues with acceleration/performance - starts and idle nicely Previous owner mentioned valve lifters-may this be the cause ? Tried to capture sound however my iPhone ignored this frequency for some reason and I will try to do it with other phones so I can post it here… Inspected clutch and variator, rollers are like new, replaced belt as it was worn, cleaned dust and re-finished clutch and bell with sandpaper as it was slipping, new variator guides as there was quite lot of sideways movement, crankshaft has no play by hand/at high rpm on center stand so i assume it’s not cvt related Any input will be helpful


here is audio where you can hear that sound whenever i WOT http://sndup.net/9h8k7

[Iahawk]

welcome to the forum! I do hear something a little different than I would have expected in your audio clip..if you've pulled cam cover and adjusted valves properly and all looks good I'd take a look at exhaust gasket from head. Possibly an exhaust leak?

[Ruffus]

Welcome here! 0.10 mm for both IN/EX is too tight.
 0.12 mm is correct.
Valve lifters I would exclude, sound different.

At second 53 and second 59 on your soundtrack I might hear a sound which is unusual. Could be the variator?

Did you check the variator boss (thick round piece which holds your variator on the crankshaft).
There are sometimes pittings and loose chrome parts.

Did you check on the scoots RH side?
Aircooling fan might cause a certain sound too.

BUT: nearly every scoot sounds different, depends on many factors.
If I meet with friends, who own four and six cylinder Hondas, they always ask me whether I left some nuts and bolts loose in my CVT.

[Prostidude]

hey guys, thanks for the reply. i havent checked exhaust gasket as i dont think there should be difference between no-load and load, i thought if it was gasket it could be heard when on center stand...for the unusual sound at 53 and 59sec, its probably toolbox as i carry one under seat so i probably rode over small bump and it rattled little bit :-) i was thinking maybe it has something to do with PAIR system? from what i've read it should dump some fresh air into exhaust to burn excess fuel that leaves cylinder unburnt-this might explain why i hear something similar to spark knock? and it would probably resonate thru head back into valve cover part resulting in echo ? it is weird it is always there, only after half throttle and only under load... i am running out of ideas however i will visit kymco authorized repairguy in my hometown to let him listen to this, he has years of experience with kymcos so he might be able to help without actually taking apart half of the engine hehe, will post what i find
and to the valve clearance, i used 0.1 feeler gauge however, its very loose on both valves(still cant stick in 0.15) so we are somewhere between 0.1-0.13+- and as there are no start/performance troubles and tapping i guess its all fine =)

[shibahiro976]

I have a Kymco Agility R16+ (2021), I have the same problem and noise. All Identical!
On my scooter I have checked and tightened all visible bolts (kickstand, body, etc), replaced the variator (whit malossi), belt, clutch and bell! The noise is still there! I don't hear it when it's on the stand, stationary! (at least I think so). I was thinking a problem with the exhaust, manifold area (gasket/bolts) or internal (some internal broken part!).
When we are sitting on the scooter our weight probably affects the position of the exhaust.()
The scooter is perfect in performance. Just this noise on acceleration. I follow this discussion. You are the only one with the exact same problem as me!
I was looking for information on this and found this post!

I forgot... I have already change motor oil, trasmission oil and spark plug!

[Stig / Major Tom]

Me, I'm waiting on prosti's report from his experienced Kymco mechanic..
This fellow can listen to it firsthand.
My guess is it's an exhaust sound, occurring when scoot hits  revlimiter???
Stig

[shibahiro976]

here, in my town, no kymco's mechanic has solved the problem! Everything is ok, in their opinion I'm waiting for a reply from Prostidude, he could help me out too!
Incidentally, it is the only one I have found on the entire planet with the same noise as my scooter! 

[shibahiro976]

hey guys, thanks for the reply. i havent checked exhaust gasket as i dont think there should be difference between no-load and load, i thought if it was gasket it could be heard when on center stand...for the unusual sound at 53 and 59sec, its probably toolbox as i carry one under seat so i probably rode over small bump and it rattled little bit :-) i was thinking maybe it has something to do with PAIR system? from what i've read it should dump some fresh air into exhaust to burn excess fuel that leaves cylinder unburnt-this might explain why i hear something similar to spark knock? and it would probably resonate thru head back into valve cover part resulting in echo ? it is weird it is always there, only after half throttle and only under load... i am running out of ideas however i will visit kymco authorized repairguy in my hometown to let him listen to this, he has years of experience with kymcos so he might be able to help without actually taking apart half of the engine hehe, will post what i find
and to the valve clearance, i used 0.1 feeler gauge however, its very loose on both valves(still cant stick in 0.15) so we are somewhere between 0.1-0.13+- and as there are no start/performance troubles and tapping i guess its all fine =)

news?
Thank you!

[shibahiro976]

hello everyone!
yesterday i noticed that i have a small tube on my agility, disconnected!
Could this be the cause of the noise?
one of these days, i'll try to open it and check!
Do you have this little tube? What should it be attached to? It has a locking clip!

[Stig / Major Tom]

hello everyone!
yesterday i noticed that i have a small tube on my agility, disconnected!
Could this be the cause of the noise?
one of these days, i'll try to open it and check!
Do you have this little tube? What should it be attached to? It has a locking clip!

No.
That looks like the end of the 'puke tube' - a tube which drains the airbox. Open or plugged it shouldn't be making any detectable noise. And the other end is properly connected - the visible end connects to nothing. It usually has a plug in it - held by that clip you see. Remove the plug to drain the airbox. Plug it with something when you get a chance.

[shibahiro976]

No. That looks like the end of the 'puke tube' - a tube which drains the airbox.

unfortunately it is not the tube wich drains the airbox (see pic!)
this tube comes from the bottom! It arrives in the head cover area.
Could someone check the area and take some photos for comparison, please?
thanks for your time!

[Ruffus]

Simply take off tupperware (seat off, METIN box out) and have a look where it belongs to.

[shibahiro976]

Simply take off tupperware (seat off, METIN box out) and have a look where it belongs to.

I cannot check it before Sunday. I was hoping for someone with a similar problem before I disassemble