Need help identifying rattling noise from lower right CVT cover (2023 Brute Force 750)

[Puxlya]

Hi everyone,


I’m trying to identify a rattling noise on my 2023 Kawasaki Brute Force 750 (currently 60.6 engine hours).


I’ve already spent quite a lot of time diagnosing it, but I still haven’t found the cause.


Symptoms

• The noise comes from the lower right corner of the CVT cover.
• I confirmed this using a mechanic’s stethoscope.
• The engine itself sounds normal.
• Both spark plugs look perfect.
• No oil consumption.
• Full power, no noticeable loss of performance.
• Top speed is still around 110 km/h (GPS).

When does the noise occur?

• Immediately after a cold start: no rattling.
• I have to ride about 10–20 meters before it appears.
• Once it appears, it is only present while the ATV is moving.
• It starts around 5–10 km/h.
• Engine braking (KEBC) works perfectly.
• CVT belt does not slip.

Additional information


There is also a light CVT/transmission whistle whenever the ATV is in gear while standing still. Pressing the brake pedal makes the whistle louder. Shifting into Neutral makes it disappear immediately.


This whistle has been there almost since the ATV was new, so I’m not sure if it’s related.


What I’ve already checked

• Engine oil level is correct.
• No metal particles in the oil.
• Spark plugs are clean.
• No smoke.
• No fault codes.
• No noticeable vibration.
• The engine starts and runs well.

My question


Has anyone experienced this exact type of rattling?


If yes:

• What was the actual cause?
• Was it the KEBC mechanism, EBS, primary clutch, secondary clutch, CVT, or something else?
• What fixed it?

I’m especially interested in replies from owners who actually found the cause, not just guesses.


Thanks in advance!

 

[Alan]

That is a genuinely tricky one to chase down, especially since you've already ruled out the obvious stuff like oil and plugs. The detail about it only showing up once you're moving, and getting louder under braking, tells me you've been paying close attention rather than just guessing. What got you into the Brute Force in the first place, work machine or more for trail riding?

 

[Puxlya]

That is a genuinely tricky one to chase down, especially since you've already ruled out the obvious stuff like oil and plugs. The detail about it only showing up once you're moving, and getting louder under braking, tells me you've been paying close attention rather than just guessing. What got you into the Brute Force in the first place, work machine or more for trail riding?

Thanks! I bought it mainly for trail riding and exploring forest roads. I really like the ATV overall, but this rattling noise has been driving me crazy because I can’t figure out whether it’s normal or an actual mechanical issue.





Have you ever heard a similar noise on a Brute Force? Especially one coming from the lower right side of the CVT cover that only appears after riding 10–20 meters

 

[Alan]

Trail riding and forest roads sounds like the right use for that machine. The bit about it only starting after 10-20 meters seems like a useful clue for whoever knows these inside and out.