Downtown 125i vibrates when 5000 to 6000 rpm

[kasunth]

I recently bought a downtown 125i (2019 model). Current mileage is 300km. When i accelerate it (from 0 speed), its starts vibrating at rpm between  5000 to 6000. But when I hit 7000 rpm and in speeds like 80kmph, i don't feel any vibrations. Is this normal? Will these vibrations go away with time? Or any issue with the bike?

[TBR125]

Certain RPM's cause oscillations that match the frequency of the bike frame. The vibration frequency varies per bike and is never an issue for some. As to what could cause it, I can't say. On my scooter when I hold the rear brake while idling the bike vibrates badly.

[stuo]

I second TBR's explanation. Live with it...or go crazy trying to stop it. In any case tighten all the fasteners you can before they vibrate loose.

[Neil955i]

Biggish singles all have this form of character! Guess you learn to live with it. My brother’s old BSA 250 shook like a wet dog at tickover [emoji23]


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[kasunth]

Hi all,
Thanks for your replies. But i recently tested a DT 350i and didnt felt any vibrations at all. Thats why i thought to ask it here. And i feel the vibration from the foot area.

[Neil955i]

Not familiar with the DT350, but I know that some maufacturers (eg Honda) have made some big singles with a balance shaft to eliminate / mitigate vibration.  Kymco had engineering links with Honda in the past so maybe the DT has something engineered in?

[TBR125]

I had the heavy floor board vibration for about 1,500 miles this year. It got to a point my feet would go numb but gladly the issue went away after a few months.

[Neil955i]

... my feet would go numb but gladly the issue went away after a few months.

That's my sort of solution, it fixed itself!

[stuo]

PS to my first response: With the cover off watch the variator action as someone twists the throttle up to 6000 RPM. There should be no shaking or out-of-round movement of variator or clutch assembly. If you are new to this there are youtube vids on servicing CVT's. CVT's are all basically the same across the different brands of scooters.

I'd service (remove, clean and inspect) the variator, and replace the rollers. If a roller is hanging up (flat spot) or the wrong weight that could cause the vibration. Generic rollers are around $20 on ebay. Inspect and replace the belt if in doubt. If you have a gram scale (Harbor Freight) make sure the new rollers are all within .1 gram of each other.

At those high RPM's I now doubt this is just the frame resonating; I suspect something is out of whack causing the vibration. Let us know if you find the answer. Good luck.
 

[CROSSBOLT]

Have the second DT300i and sense no vibrations you describe. However, assuming some similarity in consrtuction, I would suggest careful inspection of the rubber-like mounts for the engine unit as some of those may have loosened slightly. Not only the pivots for the unit but the longitudinal damping rod that has rubber mounts at each end.

[Iahawk]

this is unlikely if it's only happening between 5-6000 rpm...but any chance it could be clutch chatter?...where the clutch pads get glazed over and you get a lot of chatter and vibration when initially accelerating?

Wait, is your listed mileage correct? 3 Hundred KM? (180 miles)? if so, are you still under the factory warranty?

[Yoni159]

I have downtown 350i with 45000km and i also have this problem i always had this problem its single engine its vibrate...