To Lube or not to Lube on V7 Driveshaft Splines

[antmanbee]

I have the rear wheel off on my  2013 V7 and was going to lube the splines until I read this thread https://wildguzzi.com/forum/index.php?topic=99167.0.
I have always lubed the splines on my big block Guzzi's but after reading this thread I am not sure if I should do the V7 splines.
So should I just leave it alone, or just clean the splines and reassemble with no lube,
or clean and then grease?
Is there a down side to lubing the splines? I have always lubed them but guzzisteve and a couple of others don't.
I have a day or to to contemplate it because the rear wheel is off to redo one leaky spoke on the rim where I had sealed them to run tubeless and it takes time for the sealant to fully cure.

[SmithSwede]

You’ve seen my original post, where I had the final drive components fail.   

I’m still a believer in lubing the splines; I don’t see a good argument for why not lubing them would be better than lubing them.  The components are exposed to regular and fretting corrosion, and the grease should help.

Maybe if the grease was exposed to dust and grit in the outdoors you would not want the grease attracting that stuff, but the splines are enclosed in the swing arm. 

I think maybe my mistake was not cleaning off the old grease before slathering on more.   After I replaced those parts, I made it my routine to clean off the old grease re-grease every time I replaced a rear tire. 

The bike is now just over 150,000 miles and splines are fine. 

[chrisfer]

Yes lubing the splines is better, and that's what Moto Guzzi does at assembly.

[John A]

I’ve had good results by greasing the splines. I clean almost like for a paint job. Then I spray on a moly dry film lube, cure it with a heat gun and over that goes sticky Wurth grease from MG Cycle. It easily lasts between tire changes without abrasive red rust showing up. If I couldn’t do it myself, I wouldn’t pay a dealer to do it although it doubles spline life.

[mechanicsavant]

Lube=life . Nuff said !

[moto-uno]

Yes lubing the splines is better, and that's what Moto Guzzi does at assembly.

I've owned new guzzi' since 1983 and not a single one of them has a trace of lube on the any of
the splined surfaces , much less the axles !  Peter

[Frenchfrog]

That's because they are cheapskates  at Mandello Peter

[John A]

When you’re working at an assembly line, having to take the time to lube adds up to time spent in a process that is considered preventative maintenance. As long as it gets well past the warranty period it may be un necessary, depending on your point of view.

[SmithSwede]

Another thing to consider.  The final drive is splined for a reason.  It must move fore and aft to accommodate the movement of the swingarm. 

That means when you are applying power to the rear wheel, and also hitting bumps, you are forcing the splines to slide under load.  Seems obvious to me that you would want lubricant for that condition.   

[antmanbee]

The job is done and I am very glad I disassembled the swingarm and cleaned and greased everything.
Even though the bike only has less than 4K miles, it is 9 years old and had spent the last 5-6 years out under a couple of tarps.
There was a lot of crud and rust and grime. I was surprised that it was that bad with only 4K.
My opinion is it would have been a disaster waiting to happen if the proper attention was not given. 

[Huzo]

If it’s going in and out, you don’t want it dry….
As that great philosopher Dr Zachary Smith once said….

.Oh the pain William..The pain…!

[antmanbee]

If it’s going in and out, you don’t want it dry….
As that great philosopher Dr Zachary Smith once said…..Oh the pain William..The pain…!

If that was the first response the rest of the thread was not necessary.
I'm not that smart and things need to be explained to me in terms I can understand.

[Huzo]

If that was the first response the rest of the thread was not necessary.
I'm not that smart and things need to be explained to me in terms I can understand.

Yep.
There’s something primal about certain aspects of motorcycle preventative maintenance.
This, I suggest is one of them…

[John A]

I concur with the above statement 

[chrisfer]

I've owned new guzzi' since 1983 and not a single one of them has a trace of lube on the any of
the splined surfaces , much less the axles !  Peter

Of the four small new blocks that I have owned since 1995, the splines have fortunately always been lubricated.

But before the V7 850 which finally has a small hole at the bottom of the arm, the 750 tended to keep a lot of humidity, even water in this place and the lubrication did not last very long given the constraints and movement of this coupling .

[Pescatore]

Another thing to consider.  The final drive is splined for a reason.  It must move fore and aft to accommodate the movement of the swingarm. 
....

What an interesting topic. This thread (and the one linked) had me thinking about that fore/aft motion. Thanks for explicitly spelling it out for my slow brain.
I wonder how a double cross u-joint helps.  Maybe I misunderstood the hints in the linked thread.

Anyway, I am guessing the same motion happens at the gear box output shaft.
I will be cleaning and re-lubing at the first opportunity.
Thanks for the heads up.

[Pescatore]

This fore/aft motion is hard to imagine.
The transmission, swingarm, rear drive, wheel and axle are all bolted together.
So it must be a real small displacement. Mind blowing to me.

[SmithSwede]

What an interesting topic. This thread (and the one linked) had me thinking about that fore/aft motion. Thanks for explicitly spelling it out for my slow brain.
I wonder how a double cross u-joint helps.  Maybe I misunderstood the hints in the linked thread.

Anyway, I am guessing the same motion happens at the gear box output shaft.
I will be cleaning and re-lubing at the first opportunity.
Thanks for the heads up.

Yes.  Fascinating stuff.   

The V7 final drive has a single U-joint, which means at any angle other than zero, the input and output sides of the drive train are out of phase.   By necessity, they cannot rotate at the same speed, so there is heat and vibration created as a consequence.  I think Newton figured that out hundreds of years ago.  Same average speed of course, but not same instantaneous speed.  That’s one reason you want rubber in the cush drive, to dampen this unavoidable vibration. 

You can get away with this arrangement if the suspension doesn’t have much travel (angle) and power output is modest.  Like a Guzzi V7 or BMW airhead.  Otherwise you probably want two U-joints. 

Another fascinating topic to research is fretting corrosion.  Splines and other items will wear simply because they are subjected to small, repetitive motions.  Even if little power is involved, and even if the relative angle is zero.  Electrical components can suffer from fretting corrosion just being exposed to a vibratory environment. 

Lubrication helps prevent fretting corrosion.   

Getting back to our final drive splines, I suspect the ideal lubrication regime would be a circulating oil bath.  The flowing oil would flush away wear particles and keep components cool.  Slathering on grease is probably a distant second choice in terms of wear prevention.

 I think that’s what happened to me.  Yeah, i greased the splines, but initially I didn’t clean off the old grease.  So the old grease just kept the metal wear particles in suspension, forming a grinding paste. 

[Bulldog9]

Is an extra 20-30 minutes and well worth it.

[Huzo]

And not forgetting.
There is a finite distance that the output shaft at the gearbox and the input shaft at the bevelbox are separated with respect to each other.
If you imagine a straight line drawn between these two points when the swingarm is deflected downwards, you will arrive at a dimension and the straight line you visualise, passes underneath the swingarm pivot.
When the swingarm is loaded, the centre of the bevelbox describes an arc, centred around the swingarm pivot and as it rotates clockwise (when viewed from the brake lever side), the distance from the centre of the bevelbox to the gearbox output shaft….? Increases.
Until the shaft/pivot point/ bevelbox are aligned, any more than that and the distance begins to reduce again.

So it can be seen if you’ll pardon my rather crass and possibly inflammatory analogy.
As the body goes up and down…?
The shaft goes in and out….(So to speak…)

[Huzo]

Anyway, I am guessing the same motion happens at the gear box output shaft.

No, not quite.
The gearbox end of the driveshaft unit, has a spring clip that resists the tendancy of the front spline to travel axially on the spline.
When you remove the unit for servicing, you need to hold the shaft in line with the gearbox axis and give it a sharp tap with a copper hammer.
All of the axial displacement is taken up at the bevelbox end.

[Dirk_S]

Worth noting that the V7 850s now have a u-joint on both ends of the driveshaft, like the V9s have been using all along. I haven’t checked, but I’m guessing it’s the same part number. The rear spring is also gone.












I checked the V100 driveshaft, expecting to see the same type, but that actually looks like the older V7, although I don’t see a spring:

The gearbox end of the driveshaft unit, has a spring clip that resists the tendancy of the front spline to travel axially on the spline.

Hmm, I’ve never felt I had to hit my driveshaft with anything to get it to line up. I simply spin the rear end of the driveshaft until the outer teeth of the gearbox shaft and the inner teeth of the driveshaft mate up.

[Pescatore]

I think I get it.  The pivot point of the ujoint and the swingarm are not perfectly aligned.
That creates two arcs with slightly different radius.
The swingarm is bolted to the bevel box, therefore the drive shaft has to be able to adapt to the arc of the swingarm.

Perhaps some bikes have the perfect alignment and the shaft doesn't need to slide at all.  Then, lube might not  play a big role, except for fretting as SmithSweed explained.
I'm glad antmanbee asked the question. I would have never found the original thread.

Dirk, the double ujoint makes my head explode. I'm not sure what it does, given there is still one pivot point.
Maybe there is lateral motion at the rear end,
Edit: the shaft must be angled like in the new V100, but...
I probably derailed this thread too much already.

[Huzo]

Hmm, I’ve never felt I had to hit my driveshaft with anything to get it to line up. I simply spin the rear end of the driveshaft until the outer teeth of the gearbox shaft and the inner teeth of the driveshaft mate up.

The tap that I described was not to get anything to “ line up”.
It’s to coax the front spline to slide off the gearbox shaft, the spring clip sits in a shallow groove and it’s function is to stop the front spline from sliding on the gearbox shaft during normal operation.
Now..
The point where the front spline attaches to the ‘box can be considered as “A”
The pivot point of the front uni as “B”
The bevelbox centre as”C”

When the swingarm is loaded and not deflected through an angle, A,B and C are all in line and and the distance from the gearbox spline to the bevelbox spline is exactly that of the UJ unit.
No worries but..
When the swingarm is deflected through an angle, the straight line distance of A to C, is NOT  the same as when it is co axial with the gearbox.
It’s because the output shaft of the gearbox is FORWARD of the pivot point at the swingarm.

[Off @ 90]

I learn't my lesson back in 1980 when the u joint failed on my MG 850GT through lack of lubrication .Fortuneatly didn't leave me stranded potentially  dangerous too if it locks up the wheel .
 Just done my Stornello it's a good chance to clean up and lube around the clutch pushrod lever with the swing arm removed and check the  swing arm bearings etc. Out of interest my old 850 GT had a double universal ( expensive too back then on apprentice wages) Interestingly  this becomes a contant velocity joint as one universal cancels the other out when there is an angle between the shafts. As SmithSwede explained  the V7 750 is single  cross universal so not constant velocity and the speed variation taken up by the  cush drive rubbers .