Identifying noise - Does this sound bad to You ?

[boksaman]

I have just bought used Kymco Downtown 2011 300i with 46 000 kilometers.
I'm pretty happy about it - plastics are good, its goes straight, looks like it was not fallen from it, i love the acceleration, brakes, lights etc.. looks good - so far had no problems.
Only thing i have noticed is "clank" sound coming from variator housing, it happens when i accelerate (pull the throttle) from stop and when i lay off the throttle suddenly - i can hear it once or twice - sounds somewhat metallic. It happens also when the bike is on the main stand when i pull the throttle.
I have recorded the sound in order to help with identifying problem



Does anyone have experience with this sound and does it indicate serious problem? Any help is greatly appreciated.
Thanks

[CROSSBOLT]

Exhaust leak. I vote for an exhaust leak anywhere from the pipe connection at the cylinder head to the slip-on connection at the front of the muffler. Rusted holes are also a possibility. Otherwise, sounds good!

[boksaman]

CROSSBOLT Thanks for the quick answer, i'll make sure to do the full inspection ASAP. I have ordered filters, oils, etc for regular service so i'm looking forward to work on this machine. Today in store i've seen some sort of  kit for fixing minor exhaust holes - hope that will suffice if minor exhaust leak is the problem..

Does anybody else has suggestions what this noise can be ?

[Iahawk]

doesn't really sound metallic to me..but difficult to tell from a video. If it's not an exhaust leak like Crossbolt suggested you can always take the cvt cover off and look to make sure everything is working properly.

[CROSSBOLT]

CROSSBOLT Thanks for the quick answer, i'll make sure to do the full inspection ASAP. I have ordered filters, oils, etc for regular service so i'm looking forward to work on this machine. Today in store i've seen some sort of  kit for fixing minor exhaust holes - hope that will suffice if minor exhaust leak is the problem..


Does anybody else has suggestions what this noise can be ?

This is a good machine. More good points than bad points. Keep us posted!

[boksaman]

doesn't really sound metallic to me..but difficult to tell from a video. If it's not an exhaust leak like Crossbolt suggested you can always take the cvt cover off and look to make sure everything is working properly.

I will disassemble CVT in next month or two, and post videos here and notify if i manage to fix issue.

One of things i need to check is that maybe belt is slapping on CVT housing like in this video -

[francuz69]

Boksa, jesi li iz Srbije?
If not, let me switch to English. Me too bet on slipping belt. I have just rebuild my transmission. Disassembled and cleaned up everything, changed rubbish RMS rollers with Polini ones, and changed Bando belt with Mitsuboshi one. I had similar sound like Yours followed with "takatakatak" sound when revs were idling. Everything symptom i had was because of wrong belt. When compared new belt with the old one, old was not quite for my scooter. Really similar but not quite the same. The old one is few mm longer and one mm narrower. That's why my belt was slipping.
I recommend buying original or Mitsuboshi belt exactly for DT 300 and i am pretty sure Your "sounds" will dissapear.

[boksaman]

Boksa, jesi li iz Srbije?
If not, let me switch to English. Me too bet on slipping belt. I have just rebuild my transmission. Disassembled and cleaned up everything, changed rubbish RMS rollers with Polini ones, and changed Bando belt with Mitsuboshi one. I had similar sound like Yours followed with "takatakatak" sound when revs were idling. Everything symptom i had was because of wrong belt. When compared new belt with the old one, old was not quite for my scooter. Really similar but not quite the same. The old one is few mm longer and one mm narrower. That's why my belt was slipping.
I recommend buying original or Mitsuboshi belt exactly for DT 300 and i am pretty sure Your "sounds" will dissapear.

Da da iz Srbije sam Kako si pogodio ? (Yes I'm from Serbia, how did you guess?)

Thats great news, i have talked with parts store yesterday and they offered "Mitsuboshi" belt for my bike when i asked for sevice/maintenance parts, lubricants etc - now i'm definitely gonna buy that part.

Also i was browsing online for replacement belts, and got stuck trying to figure out what is exact part number for my bike:
-23100-LEA7-E00 or
-23100-LEA7-E01

What do you think is this item worth ordering (if the part number is correct)?:

https://www.aliexpress.com/item/4000668370575.html?spm=a2g0o.cart.0.0.73ad3c00CpSsft&mp=1

[francuz69]

I'm not sure that i would recommend buying Chinese belt from aliexpress. Only experience i had with Chinese belts was more than 15 years ago when i used to drive Chinese scooter. Bought it brand new and the belt snapped after 2 or 3 thousand km.
Mitsuboshi should last 20K km.
My advice is: save some money and buy the real deal!

[CROSSBOLT]

Da da iz Srbije sam Kako si pogodio ? (Yes I'm from Serbia, how did you guess?)

Thats great news, i have talked with parts store yesterday and they offered "Mitsuboshi" belt for my bike when i asked for sevice/maintenance parts, lubricants etc - now i'm definitely gonna buy that part.

Also i was browsing online for replacement belts, and got stuck trying to figure out what is exact part number for my bike:
-23100-LEA7-E00 or
-23100-LEA7-E01

What do you think is this item worth ordering (if the part number is correct)?:

https://www.aliexpress.com/item/4000668370575.html?spm=a2g0o.cart.0.0.73ad3c00CpSsft&mp=1

I agree with francuz69 that aliexpress is probably a poor copy of Mitsuboshi.

Don't know the differences in part numbers.

Please tell us when you find out the cause!

[boksaman]

Today i have disassembled cvt housing and confirmed that belt is making noise while hitting cvt housing - proof lies in black marks on housing underneath & over the belt as seen in pictures below:
housing bottom part - underneath the belt:

housing top part - over the belt:

here is the video


i believe all parts are stock, belt seems brand new (no cracks) - can anyone guess why would belt act like that and have a lot of slack. I will post below all pictures and videos that can help with diagnosing the issue

on belt is written: MITSUBOSHI KYMCO 23100-LEA7-E00 made in japan

variator close up

clutch spring seems bit rusty ?

belt slack:


with more throttle:

[CROSSBOLT]

Today i have disassembled cvt housing and confirmed that belt is making noise while hitting cvt housing - proof lies in black marks on housing underneath & over the belt as seen in pictures below:
housing bottom part - underneath the belt:

housing top part - over the belt:

here is the video


i believe all parts are stock, belt seems brand new (no cracks) - can anyone guess why would belt act like that and have a lot of slack. I will post below all pictures and videos that can help with diagnosing the issue

on belt is written: MITSUBOSHI KYMCO 23100-LEA7-E00 made in japan

variator close up

clutch spring seems bit rusty ?

belt slack:


with more throttle:

What I see on the bottom of your housing is rubber dust. I also cannotbsee the belt slap the housing in the first video.

[boksaman]

What about that picture named "housing top part - over the belt" ? I'ts easier to see those are marks made by belt

I agree that is not so easy to see the belt hitting on this video - i will try to record better video, maybe even in slow motion, one thing i'm sure now is that sound is coming from inside the cvt housing in my opinion.

[Ruffus]

@boksaman,
for me it is clearly the V-belt slapping at least at the lower housing. Since you don't know what the previous owner did or let somebody do on this scoot, l would risk an original belt to buy and mount. It's most probably the less expensive remedy.

[mousejunks]

Yep new belt, plus a clutch spring as it seems to be riding too low in the rear pulley.