Light rattle in gearbox when pushing my bike.

[docc]

1 hour ago, Walterg said:

Yes. That one.

Okay (whew!), that is not so hard to replace . . .

[Walterg]

Yeah. I'll fix that this week when I have a look at the clutch.

 

[Walterg]

I fixed the slipping clutch. The cause was a big blob of grease that I somehow managed to get on the clutch plates and did not notice during assembly.  I also fitted the rubber O-seal on the drive shaft.

After I checked the gearbox a while back I have been riding the bike a few times now (about 300 km) and I did not come across any issues indicating there is a problem with the drive train / gearbox. This morning though my speedometer stopped working. The cable 'looks' fine but I will check it when I get home tonight. The idea that the issue is with the shaft that extends from the final drive shaft into the gearbox (Gearbox outgoing) is growing. Although at this moment I can't find any picture or drawing which shows which part drives the speedometer transmission.

I have a one week holiday planned with the bike starting the 29th of August. I hope it will be clear and fixed by then.

[docc]

This image depicts the driven shaft system from the gearbox (as well as the early V11 external angle drive at the top).

Notably, there is a second thrust washer (not shown) beneath the lower spindle/pinion/shaft . . .

[Walterg]

Thanks for the picture Docc.  So far I haven't been able to find anything on how the wormwheel bushing in the gearbox that drives the spindle sits on the shaft.

I unscrewed the speedo cable and found that it was just broken. Again no indication as to what is causing those sounds. I rode 120km today and I rode the bike pretty hard but no indication that anything is wrong with the gearbox.

[docc]

So, does it still have the rolling rattle/ clicking in gear with the clutch lever pulled in?

[Weegie]

Disclaimer I only know the 5 speed box BUT that speedo drive assembly looks identical to the 5 speed.

ASS-UMING it's the same then here are some pics from the 5 speed, if they are different I'm sure @docc will jump in

The Worm drive that is turned by the layshaft is held onto the layshaft by a small steel ball, like a ballbearing. It sits in the longest groove in the layshaft and is held captive by the layshaft nut

 

 

REMEMBER THIS IS A 5 SPEED THE 6 SPEED COULD BE DIFFERENT

Did you remove the drive assembly, that bottom washer can get left behind and (if it's like the 5 speed) fall into the box and create mayhem

Don't take any of this as correct until somebody familiar with the 6 speeder verifies that it's similar

[docc]

The drive in the first two images looks identical while showing the lower thrust washer missing from my assembly image.

The odometer drive from the lay shaft ("Transmission" shaft?) looks different from the images of the 6speed. I've not has eyes on this, but recall @Rolf Halvorsen helped me understand the odometer drive gear is captured on the shaft. Frustratingly, that drive gear is shown in the parts catalog as part of the speedometer assembly, not the gearbox!

 

[Walterg]

The rattle disappeared after I screwed the gearbox back in the bike again the first time. Since I messed up he clutch the first time I had to take the gearbox off again. After putting everything back together again the second time the rattle is still gone but the clunking sound you hear when you push the bike back and forth and change direction from forwards to backwards (again with the bike in gear and my hand pulling the clutch lever in) seems louder.

The bike rides lovely though. During the ride I don't perceive any weird sounds or unwanted movement in the drivetrain.
Changing gears is fine like it has always been.

Indeed I now understand that this 

and this

should be in the same picture.

 

[Walterg]

Can somebody explain what this does? I think it is supposed to 'dampen' shocks coming from the rear wheel.

[Walterg]

By the looks of it part 15 is made out of rubber and sits between parts 13 and 17 to take the impact of sudden radial loads.
The discs (parts 18) form a Belleville spring and catch the axial movements caused by the rear wheel going up and down and thus pushing the drive shaft into the gearbox.
Right?

[MartyNZ]

On 8/12/2022 at 6:52 AM, Walterg said:

Can somebody explain what this does? I think it is supposed to 'dampen' shocks coming from the rear wheel.

You're right about that assembly dampening driveline shocks. The standard cush drive in the wheel is too stiff to completely do this by itself.

[docc]

3 hours ago, Walterg said:

The rattle disappeared after I screwed the gearbox back in the bike again the first time. Since I messed up he clutch the first time I had to take the gearbox off again. After putting everything back together again the second time the rattle is still gone but the clunking sound you hear when you push the bike back and forth and change direction from forwards to backwards (again with the bike in gear and my hand pulling the clutch lever in) seems louder.

The bike rides lovely though. During the ride I don't perceive any weird sounds or unwanted movement in the drivetrain.
Changing gears is fine like it has always been.

Because of that gearbox "cush drive" stack (not the one in the reardrive), the rear wheel has about 50mm/ 2 inches of rolling "freeplay"  when the direction of rotation is reversed.

This is normal.  It also makes the V11 6speed very challenging to ride smoothly in and out of corners.

Yet, I suspect you have solved "whatever" the original issue was, @Walterg. Also gained, and shared, significant V11 experience. Thank you for keeping us informed! And well done!     

[pete roper]

Errr? Not quite.

The driveline shock absorber and is a face cam type. The two cams parts #15 and the collar at the back of assembly #16 rotate in relation to one another. As a torque loading is imposed, either by suspension movement by the shaft or, more seriously by shock loadings imposed by sudden acceleration and gear changing up and down the box, the two cams run up against each other and the Bellville washer tower acts like a spring to absorb the energy. When the load is removed the energy is discharged back through the cams to the shafts.

The free play between 'Power on' and 'Power off' as detectable by rotational movement of the rear wheel when the engine is stopped but engaged in a gear has nothing to do with the shock absorber. It is simply backlash between the engagement dogs of the gears. There has to be backlash to allow the rapidly spinning but differentially speeding dogs to slip into engagement. If they fit precisely together the chances of them slipping into engagement would be negligible. The wider the 'Gap' between the dogs the slicker the engagement but, unfortunately, the greater the hammer loading on dogs and gear teeth as one goes from throttle off to throttle on and visa versa in any gear.

Probably the best example of the dangers of increasing this backlash in a Guzzi gearbox can be found in the early Carb Sports and Daytona 1000 models with the old five speed box. In an attempt to speed up the gear change without spending any money the selector dog collars and pinions went from the long standing six dog engagement to three dog. This leads to ENORMOUS radial travel between power off and power on meaning when the gear is selected and you are accelerating and decelerating the dogs have much longer to themselves accelerate and decelerate before power or braking is delivered and they hammer the living bejaysus out of themselves! This is absolute murder on the pinions and Sport C gearboxes in particular are terribly prone to bashing the case hardening off fifth gear closely followed by third before the rest of the box goes out in sympathy!

The fact that many owners don't get the fact that the word 'Sport' means that you're supposed to ride them like the hounds of hell are chasing you and potter around at sub-4,000rpm lugging the entire driveline, (Which incidentally doesn't have a rubber cush drive in the rear wheel hub.) which simply accelerates the rate at which they beat themselves to death!

After those two models the factory went to a compromise five dog engagement system and reincorporated the rubber cush in the rear wheel. This was a satisfactory compromise. Gear changes were a tiny bit less like dropping a brick in a bucket and the boxes no longer beat themselves to death. This system remained extant until the demise of the five speed and the rise and use of the first of the six speed, four shaft boxes used in the V11.

[docc]

I had the chance to roll my V11 Sport back and forth, in gear, with the clutch in today. It clicked with every direction change, as expected. No noise in neutral. Seems entirely normal.