Mysterious Rumbling
 

There is an intermittent "rumbling", "rattle" or "vibration" on my 2019 Yamaha Quiet tech when I am going about 10 to 12 mph. It seems to be from the front part of my cart although difficult to ascertain. I can hear it even while driving on smoother surfaces such as the road or cart path and often going up or down an incline. When traveling at a slower speed I do not hear it. I followed a recommendation to grease the clutch but it made no difference. Thoughts?