[Bobber Brad]

I just recently noticed that once my 2018 Bobber is up to temp, when I am decelerating in gear, there is a high-pitched kind of whining sound. When I pull the clutch in, the noise goes away. Is this my clutch plates slipping?? I don't notice any loss in performance while accelerating - and I drive this thing hard! Any ideas?

 

[Dr.Shifty]

My guess is that you are hearing the straight cut gears.

Gears can be straight or bevel (or helical) cut. Bevel cut are quiet as the faces slide along each other as the gears rotate. Straight cut don't slide, they just hit the tooth on the other wheel, then the next hit, then the next hit etc. Bevel gears induce sideways forces so they need thrust bearings that can cope with that. Straight cut boxes don't need that extra engineering. To make the bike cheaper, lighter, and less engineered they go for straight cut. The trade-off is a whining sound that is more noticeable on some bikes than on others.

Your car probably whines in reverse for the same reason. Car makers use the cheaper straight cut for reverse as you'll not be in that gear for long and only going slowly. Similarly, race cars are all straight cut and those things whine like fury.

 

[duces]

its either what Dr.Shifty said or the clutch cable may need to be adjusted i know from personal experience they can cause clutch rattle and the like if the cable is not in that happy zone.

 

[Axxehead]

I second getting your clutch cable checked then go from there if needed

 

[DDBCK]

When mine was making that noise it was the drive belt. Sounds weird I know. I also thought tranny. I rubbed a little wax on the grooved side in 2 spots & has been good since.