Motor Sound/Vibration during Deceleration

[dswangard]

Hello All.
My first time on the Forum and first time posting. Hoping someone out there can help me.
I have a 2013/2014 Empulse.
I'm hearing a sound and vibration from the bike when I come off the throttle and the motor is decelerating - as I'm off the throttle completely. The clunk or click coincides with the turning of the motor - the frequency slows as the bike slows.
A couple other things I've noticed:
1. When the regen is off due to the bike being cold the sound seems to be diminished.
2. When I engage the clutch and coast the sound disappears completely.
I think the sound/vibration is very slowly getting worse AND the bike is my primary mode of transportation... But, I've been taking public transportation the past month and riding it as little as possible.
Thoughts?

[lamber]

What have you done to diagnose/how familiar are you with motorcycle maintenance?  Have you checked chain tension?  The chain can rub underneath the swingarm if it's loose.

[Shinysideup]

Two items in your description conflict with each other:

"The clunk or click coincides with the turning of the motor..."

and then:

"When I engage the clutch and coast the sound disappears completely."

To me, this points to the sound NOT coming from the motor but possibly from the gear box. A broken tooth, maybe? Anything odd show up on the drain plug magnet during your last oil change?

[Richard230]

The first thing I would do is to inspect the condition of the chain and sprockets and to make sure that the drive chain is has the correct amount of slack.  (I always like to do the easy and cheap stuff first and then move on to the more time-consuming and expensive tasks.    )

[Shinysideup]

Agree with simple/cheap first!

 I had a tick-tick-tick noise that varied with my speed. Turned out it was a frozen link on a 20K mile chain. But holding the clutch in obviously didn't stop the chain from going around.

[dswangard]

Thanks for your responses.
Yes, I checked the chain myself and had it inspected at my local shop. In addition, I lubed the chain just to make sure that wasn't the issue.
The bike has 8000 miles and has been in for regular service. I changed the oil less than 500 miles ago and there was nothing unusual on the magnetic portion of the pan screw.
I think I'm gonna try and call Victory and see if they might have someone I can talk to.
Unfortunately, it seems no one in the Bay Area services the Empulse regularly.
Does anyone out there have a good mechanic I could talk to who knows the bike?
Thanks!
Dan

[DjouliensFR]

Hi,

I'm facing the same issue with my bike. It's an Empulse R 2015 with 9.000Kms. I observe the same strange noise mostly onto 2nd and 3rd gear. It appears when decelaring and also the noise goes down as much as the speed is descreasing.
Did you fix the issue in your case?
Looking forward to hearing from you, thanks.

[siai47]

Does the speed of the "sound/vibration" change based on gear ratio?  If the problem is on the primary side (motor, primary reduction, clutch basket, etc.) then the frequency of the noise would be higher at any given road speed in a lower gear.  If the problem is in the transmission output or final drive, the frequency of the noise would be the same at any given road speed but the drag caused by the motor in lower gears could make the problem more pronounced.  Not much help but maybe you could then determine what part of the driveline is causing the issue.

[DjouliensFR]

Yes, the "sound/vibration" become higher in 2nd gear than in the 3rd gear for the same speed. Most of the time, moving to the upper gear make the noise disappear.
Also, I tried to engage the clutch when the sound was here and despite the motor rotation was off (freewheel - 0 rpm) and the Empulse still moving around 50Km/h, the sound remains audible. So that I can confirm the issue is not the motor.
I hope it could help (and almost descriptions are clear enough  )

[DjouliensFR]

Hi, it seems the problem is fix  !
Yes, as the strange noise / vibration was coming from the gear box, I decided to change the oil. The fact is that I extracted only 650mL instead of 1 quarter (nearly 950mL).
I filled with 950mL of new AMS OIL as recommanded and the sound deseapared completly.

From my side, I'm just now trying to understand why the oil level was so low  !

[Shinysideup]

Oil on the garage floor? Drips on the bottom of the  bike? If not, then insufficient fill?