Ugly Sounds from RT Clutch/Trans

[mentalite]

I've made a video and posted to YouTube for your watching pleasure.  Man, there are bad sounds when engaging a gear.  It even seems to rattle a bit when in neutral and the clutch lever out.  Engaging the clutch quietens it.  Which component do you think is making my nasty sounds?  Trans, clutch, or both?  And is this a known issue?

 

I'm waiting for bad news either way.  Thanks for the help.

 

Ugly Sounding Video

 

[dirtrider]

1 hour ago, mentalite said:

I've made a video and posted to YouTube for your watching pleasure.  Man, there are bad sounds when engaging a gear.  It even seems to rattle a bit when in neutral and the clutch lever out.  Engaging the clutch quietens it.  Which component do you think is making my nasty sounds?  Trans, clutch, or both?  And is this a known issue?

 

I'm waiting for bad news either way.  Thanks for the help.

 

Ugly Sounding Video

 

Afternoon mentalite

 

That is pretty normal with motorcycle on center stand, rear suspension drooping, no rear wheel drag,  in gear, & large piston 2 cylinder engine idling.    

 

Everything stacks up wrong. 

 

Give it some throttle & see if the  noise & chattering goes away. Even lightly dragging the rear brake usually calms the juddering & chattering.  

 

As far as noise in neutral with clutch out-- That is usually neutral gear rattle, again normal on some BMW's due to trans being a constant mesh gearbox so all gears are spinning even in neutral. (should go away when actually riding) 

 

 

[TEWKS]

At the very end of that vid, there’s a nasty clack clack clack. My ears direct me to the FD? 

[Hati]

My '06 makes the same noises except for that "clack clack clack" at the end. As DR said, under load most of these noises go away and you should be left with some gearbox whine and tyre noise.

[9Mary7]

Is it noisy when you ride it?

[mentalite]

I'm relieved to hear that some of you experience this sound to some degree and consider it normal.  I don't notice a sound when I ride.  The more evident clacking at the end happens when I dump the clutch more aggressively.

 

I would say the noise definitely doesn't come from the final drive.  It is more from the gearbox area.  What I didn't say before is that I just completed gearbox and final drive oil changes and have verified that the fluid levels are correct.

 

I'll get it out for a good ride tomorrow and see how it feels.

[Skywagon]

The sound at the end sounds like lash to me.  drive shafts have lash...can't tell if yours is excessive or not over the net, but doesn't sound too bad.  lash is exacerbated by dumping clutch fast or engine braking then heavy throttle.

[9Mary7]

If it is quiet under load then the noise is the lash "stacking" when unloaded and extended.

 

I'd go with normal..... both mine do it........

[dirtrider]

9 hours ago, mentalite said:

I'm relieved to hear that some of you experience this sound to some degree and consider it normal.  I don't notice a sound when I ride.  The more evident clacking at the end happens when I dump the clutch more aggressively.

 

I would say the noise definitely doesn't come from the final drive.  It is more from the gearbox area.  What I didn't say before is that I just completed gearbox and final drive oil changes and have verified that the fluid levels are correct.

 

I'll get it out for a good ride tomorrow and see how it feels.

Morning  mentalite

 

As long as it doesn't make that  drivetrain lash rattle when you ride the motorcycle then you are in the good zone. 

 

As you noted, most of the noise, therefore most of the extra lash is in the trans area. This is mainly due to the trans being a constant mesh gear box (all the gears are engaged & spinning all the time that the clutch is engaged & engine running). The spinning (driven) gears are then engaged/disengaged to their respective shafts by sliding collars (dogs).

In order to be able to shift the the transmission easily the teeth on the sliding collars must be a loose fit in the pockets in the spinning (driven) gears. 

 

It's the loose fit of the dogs into the engaged gear  that gives you most of the slop.  For ease of shifting there is more slop in the lower gears than the upper gears so 1st gear has a very loose engagement.   

 

Now couple that loose dog to gear slot engagement to a drooping rear suspension that gives exaggerated  U joint working angles producing an  acceleration/deceleration to the final dive pinion on each drive shaft rotation. Now couple that  to an unloaded free spinning rear wheel with no drag,  then power the whole deal  it with a harsh-firing 2 cylinder large-piston boxer engine through a solid-center undamped clutch disk  & you  get that nasty sounding death rattle. 

 

Good news is that it goes away as soon as you put the rear wheel on the ground  with a road-load on it. 

 

 

[mentalite]

Thanks everyone for the helpful input.  You have certainly eased my mind.