Increasing clattering sound from engine VIDEO and disassembly update -Finished!

[balkoger]

Over two season used my Downtown and pass 13 000km (full milage 28000)  the clattering noise is present from the beginning. As I got to know my bike month to month and pass many service hours I try to localize this weird sound also. The bike does not have any failure which are not solved by brainstorm and calmness, but this problem suprasses me. I am willing to spend time and money on this, take of the engine if I needed to.
Appreciate any help from you and I watch every weird story if you share your experiences.
Please watch my video, I try to explain, the noise came from the crankchase or the lower part of the engine, loudest at low rpm and cold engine and same on summer time when very hot. As you can see the belt and variator removed, because many technician suggest me, that noise came from there, but I knew it wasn't. That noise easly be shown to turning the crankchase by hand
When I bought the used bike, does not have that sound, some clattering sound came occasionally, but not always.
Good to know:
I check valve clearance 4 times (every oil change), not measured differencies, good
I check chain tensioner not stuck, put back as service book request
Replace coolant (just 2 years change) not have any sign leaks or contamination
Replace the spark plug use suggested torque, working and light brown color

To locate that weird noise I plan to remove cylinder head and cylinder piston first, maybe not expensive to change gaskets, but I can check piston pin and crancshaft-rod clearance.
If there nothing special, second remove the right crankchase cover, that is the hardest for me, because there is many parts which need special tools and good skill
I hope does not need to separate the crankcase....

[Stig / Major Tom]

youtube is telling me your video is "private", and so not viewable.

Stig

[balkoger]

Thank you Stig, I changed.

[Stig / Major Tom]

1) can you locate the sound by touching your temple (side of head, above your ear) on handle of screwdriver which is touching various parts of the engine?

2) what valve clearances are you using for your measurement? Are you confident in your valve check technique?

I have nothing further...
Stig

[rdhood]

what kind of mileage are you getting?   Maybe use a stethoscope to locate the clattering?

At 28000 miles, you are right to suspect that something in the engine might be wearing out. Its just that (from sitting where I am) I couldn't possibly tell you if it is valve noise or a rod bearing that is wearing out.  I like to think that we could get closer to 50,000 miles or more on these bikes before major engine work is necessary

[balkoger]

Stig:
1. I try your first mention when I have help. (few more hands)
2. Yes I confident, always rechecked after adjustment if a had to. Feeler gauge 0.1 mm can moovable but not easily and always turn few times after recheck again. Also check adjacent gauge to measure my hand after tighten. Interestingly, they are both 0.1 mm (inlet/exhaust)

rdhood: Sorry 28000km and I change the original service part at 20000 km. That mileage nothing, that's why interesting to me.
My niece is a doctor, stethoscope is a good idea 
Valve noise Is my first opinion, but after 4 times and the noise was louder.

[CROSSBOLT]

I may not be hearing what you are but it sounds EXACTLY like both DT300i machines I have had/have. Had 22000 miles on the first and about 10000 miles on present one.

A medical stethoscope may be TOO good to track a noise from an engine! Stig's method more better.

Keep riding it. Keep sharp eye on oil at each change and watch for metal if no other symptoms show.

[balkoger]

Karl: I had to replace rear tire, so I'm not far to remove engine completely. Few gaskets and start to investigate the problem. I wont start this season with that noise, last year I keep on eye, but nothing happened in a good way, just getting worst.

[scooterfan]

I assume these scooters come with crankshaft roller bearings as well ?
If so, maybe you should rock the crankshaft shaft up and down as well as sideways. If you find any play I guess it will might make sense not to run the engine any longer.

P.S. Something else I read elsewhere some time ago - on some scooters the gaps between the coil pickups and the stator magnets at at the opposite side of the engine’s are adjustable. I would also have a look for a loose coil pickup, the gap between the pickup and the coil magnets, and even a loose coil magnet.

Or maybe a faulty bendix assemby on the starter motor could cause the bendix gear to get slightly in touch with the ring gear at the flywheel ?

I’m just guessing of cause.

[CROSSBOLT]

There is no bendix. There is a one-way roller/sprag clutch between starter and engine. Like scooterfan said about crank bearings being loose, it would not take much "looseness" to make a noise and wiggling the end of the crank would be the only way to find it.

[john grinsel]

Just ride it until it blows up or stops----wasting time and money hunting noise....is wasting time.

[Neil955i]

Just ride it until it blows up or stops----wasting time and money hunting noise....is wasting time.

Ha ha.  Man after my own heart John, don't waste valuable riding time!

[mousejunks]

Just ride it until it blows up or stops----wasting time and money hunting noise....is wasting time.

I would agree with this to just keep riding. My DT300 made a clatter all through 80,000km before it was uneconomical to repair and renew registration.

[CROSSBOLT]

I would agree with this to just keep riding. My DT300 made a clatter all through 80,000km before it was uneconomical to repair and renew registration.

Just out of curiosity, mouse, what needed repair at 80000 km?

[mousejunks]

I was rear-ended a second time around 60,000km. It wasn't a write off the time but nearing 80,000km the bike developed an engine oil leak and starting issues requiring $$$. Since the bike was being held together by mostly zip ties (due to broken fairings) it was cheaper to junk it on the spot rather than fix it or sell it.