AK550 vibration at 35mph+

[An Orange Crush]

Hello everyone I`ve been gone over a year and not riding due to some issues but I`m back in the saddle again.
I bought a brand new 2023 AK550 in April of last year, put 40 gentle miles on it and then parked it due to a knee issue.

I`m now riding again and I have 180 miles on this AK550 Scoot and I`m noticing a vibration unlike the ones I`ve found in the search on here;
other guys had a vibration and then a clunk on deceleration, I dont have that.

What I have is a vibration that quickly comes and goes at speeds around 35mph while riing.

It`s a cyclical vibration. 

Best I can describe this is like once every second or so I get a humm...humm....humm....  approximately once every half a second or so and it gets faster as I speed up.

I feel it in the floor boards and even a bit in the seat.

I`ve read the other threads on here regarding AK550 vibration on here and they were mainly about vibrating at deceleration with a clunk thrown in at 22mph, and thats not a problem with mine.

Anyhow, if you can share any thoughts I`d like to hear it~my dealer is 150 miles away lol.

[Hornblower]

Hello everyone I`ve been gone over a year and not riding due to some issues but I`m back in the saddle again.
I bought a brand new 2023 AK550 in April of last year, put 40 gentle miles on it and then parked it due to a knee issue.

I`m now riding again and I have 180 miles on this AK550 Scoot and I`m noticing a vibration unlike the ones I`ve found in the search on here;
other guys had a vibration and then a clunk on deceleration, I dont have that.

What I have is a vibration that quickly comes and goes at speeds around 35mph while riing.

It`s a cyclical vibration. 

Best I can describe this is like once every second or so I get a humm...humm....humm....  approximately once every half a second or so and it gets faster as I speed up.

I feel it in the floor boards and even a bit in the seat.

I`ve read the other threads on here regarding AK550 vibration on here and they were mainly about vibrating at deceleration with a clunk thrown in at 22mph, and thats not a problem with mine.

Anyhow, if you can share any thoughts I`d like to hear it~my dealer is 150 miles away lol.

It's a guess of course but the first thing I would check is the final drive belt. I would check the tension and the alignment. Good luck finding the problem.

[Ruffus]

Welcome back!
First thing check your tires, pressure, balance weights off?
Then check for flat spots on them, particularely front wheel? Sat for a while, didn't it?
Brake discs rusty?
Brake pads stuck?
No success or change,pls come back for Qs!

[An Orange Crush]

Welcome back!
First thing check your tires, pressure, balance weights off?
Then check for flat spots on them, particularely front wheel? Sat for a while, didn't it?
Brake discs rusty?
Brake pads stuck?
No success or change,pls come back for Qs!

Oh yeah it sat for a year and all of what your saying is probably what it is. Theres no visible rust on discs but that dont mean they arent rubbing.
Anyhow now that I`m back in the saddle I`m going ride it more and see if these things smooth out.

[nushipwright]

I have the same thing on my own and can confirm a friend's AK 550 also has this.
Both scoots have around 30K km on the clock and 2017 model.

These vibrations you describe come around 50km/h +/- 5km/h and they resurface at around 100km/h but in a somewhat lesser way?! (Or less pronounced because of noise/wind speed)
New tires, correct tire pressure, new CVT belt changed nothing.
Final drive belt still from factory but tension have been checked by dealer, still no improvement.
Brake discs and pads ok on front, rear disc has some wear (perhaps parking brake induced?), pads move freely. Fluids bled and replaced.

I am thinking of checking wear on rollers, the part of the variator housing the rollers, variator sleeve/boss and/or replace.
Friend's AK has a Malossi variator fitted but these harmonic vibrations where there with the factory variator and also present after the Malossi was fitted.

So far we could not find the source of the problem.
I am trying to think it is the nature of the beast, but I wish it would run smoother.
Let us know if you find anything.

[Ruffus]

A way to equilibrate you wheel/s would be dynamical/rotating on a balancer, put glue weights on it until it shows 0/0 on the machine.
Contrary to common opinion, wheels on scooters HAVE to be balanced to avoid mentioned issues, and additional stress on bearings and shocks.

This requires a primary wheel bearing check (front wheel both, rear within wheelcarrier).
Also the rim/s itself could be unbalanced. Has to be seen by rotating.

I had a case on a 500 where the tire itself were so unbalanced that, even after putting 120 grams of weight on it, still was hopping. New tire, had to be dropped.

So, several factors could cause this issue.

[randyo]

I have a repeating resonance, I would not call a vibration, when I am holding a steady speed, at any speed, not there during acceleration or decel.

[Ruffus]

I have a repeating resonance, I would not call a vibration, when I am holding a steady speed, at any speed, not there during acceleration or decel.

Wheel bearing front/ rear or belt?

[Hornblower]

I have a repeating resonance, I would not call a vibration, when I am holding a steady speed, at any speed, not there during acceleration or decel.

Pretty sure I have the same thing. It feels like the final drive belt to me. It's a minor problem to me unless it gets worse.

[Ruffus]

Drive belts tend to "slap" the LOWER CVT housing, particularely IF a little bit too long, which is not remarkable when all parts are new.

 But with wear and tear on spring coil,  belt AND pulleys (both drive and clutch) it becomes more prominent.
Talking about standart CVTs here, too less experience with AK 550, which drivetrain is completely different.

CVTs drive sleeve/boss, this glossy metal pipe within front pulley, causes sometimes strange sounds and vibrations when dry or worn out (pitting).

[nushipwright]

CVTs drive sleeve/boss, this glossy metal pipe within front pulley, causes sometimes strange sounds and vibrations when dry or worn out (pitting).

Exactly my thinking that is why I will dig into there next time.
New tires fitted front and rear, balanced, and rear wheel bearings replaced. Still no change, so we can rule all those out.

I have a repeating resonance, I would not call a vibration, when I am holding a steady speed, at any speed, not there during acceleration or decel.

Exactly so, and only around that speed ~50km/h, not there below or above. Not there during acceleration nor deceleration. Steady city driving speed brings it out. And yes, more audible than haptic. You can hear it but can't really feel it.

[Ruffus]

One more thing comes in my mind for this sound/noise:
-CVTs gliders (pls see pics),
upper pic burnt out/ heat deformed slider

They cause a similar noise/ vibration as a worn sleeve/boss when burnt out. If yes, take OEM stuff, inexpensive and durable.

[randyo]

my noise has gone, I put my windshield back on and it went away, replaced with tire noise

this is first time with my GIVI tall screen mounted in the low position, I like that it gives me wind at the top of my head, didn't seem to be hot like when I had it mounted in the high position. Good day to test 91°