loop frame rear wheel side play

[marc-s]

My new to me 1973 V7 850 GT California with 4LS drum brakes and police dash is giving me a hard time. I'm still rebuilding the front forks and trying to fix / replace the leaking fork collar. I used the occasion to change out all other worn parts in the fork. And to mount Dietz turn signals and clean some parts and doing some regular maintenance. On the rear wheel I then observed some lateral movement. Never noticed it during riding (only did 500km with it since I bought it). Using a dial gauge I measured the play to be approx 0.3mm from side to side (measured at the rim). It's not much I guess. The swing arm does not move, nor does the outer part of the brake drum (the cover). I did not touch the rear drive yet as it seemed to run fine and generally the PO took good care of the bike (and had a well known mechanic, specialized on guzzi twins.. but I don't like the guy). Will thus only change fluids for now. At least that was my plan until I noticed the lateral play.

Am I facing a bearing failure? Is replacing and readjusting everything in the rear drive a big thing? Never had a shaft driven motorcycle before.
Should I address it now, or just ride it and monitor / measure the play on a regular basis? I like working on bikes. But I also like riding them...  and I'm already pissed as I missed the first month of beautiful, sunny spring due to that fork rebuild and waiting ages for parts. As you can't find all the parts for vintages bikes in Switzerland I often need to order from abroad, and that takes time. And leaves me with a disassembled bike in my garage.

What would Jesus do?

[rodekyll]

0.030mm is a lot of play.  There should be none.  I'd definitely want to know why.  Is there any loose 'clunk' to the side play?

Yes, a total rear drive rebuild is not for the weak of heart or pocketbook.  I'd consider having it professionally done if you're not comfortable setting up ring and pinion gearsets.

Jesus was a carpenter, not a unit mechanic.  He'd have swapped labor for a new deck against a professional rear drive rebuild.

[oldbike54]

 do you mean play , or wheel runout ?

 Dusty

[racasey]

Having zero specific knowledge of this bike, I downloaded the Clymer Repair manual from Greg Bender's This Old Tractor, and from Tony Lammers in the Neatherlands, the parts manual.  Both of these manuals, cover the 1972 machines.

The parts manual clearly shows a range of shims available to set bearing preload, and Clymer discusses shimming the tapered bearings. 

Unless there is a substantive difference between the 1972 and 1973 models, looking for excess play in the tapered roller wheel bearings, may be a better starting point than suspecting a problem in the rear drive.

Ciao,
Dick Casey

[Dick]

Having zero specific knowledge of this bike, I downloaded the Clymer Repair manual from Greg Bender's This Old Tractor, and from Tony Lammers in the Neatherlands, the parts manual.  Both of these manuals, cover the 1972 machines.

The parts manual clearly shows a range of shims available to set bearing preload, and Clymer discusses shimming the tapered bearings. 

Unless there is a substantive difference between the 1972 and 1973 models, looking for excess play in the tapered roller wheel bearings, may be a better starting point than suspecting a problem in the rear drive.

Ciao,
Dick Casey

This ^^
.3mm = .011''  I think .3mm is out of spec. Check your manual for specs.

[mtiberio]

loops have tapered rollers at the wheels. not cheap balls. good for side cars, but more trouble/expense when they need servicing...

[John A]

There are two different issues. The rear gearbox is best left to a professional. Then the  wheel bearings are tapered like Mike said and need to be shimmed to set preload.

[Dick]

I looked it up in Chiltons. The axial play in the rear wheel tapered roller bearing (ungreased) is .05mm ( .002''). Your out of spec. Forget about the rear drive, it's not that.

[twhitaker]

Axial play at the bearing is not measured at the rim. It would be a lot less measured close to the bearing.

[Dick]

Axial play at the bearing is not measured at the rim. It would be a lot less measured close to the bearing.

Actually, I believe axial movement would be the same measured at the bearing and rim, but your right about lateral movement as the OP referred to. So maybe not out axially as much as one would think ??

[guzzisteve]

Seems like I had this problem 30yrs ago. There is a washer on axle next to brake plate. Brake plate won't move cause of stay to swingarm. Maybe someone tightened the axle pinch bolt before the nut to try and squeeze it together w/o proper spacing.  I could be wrong on this too, I didn't look in any books but the V700 that runs has one.

[Antietam Classic Cycle]

http://www.thisoldtractor.com/moto_guzzi_loopframe_wheel_bearing_adjustment_shimming_set_up.html

[Tom H]

http://www.thisoldtractor.com/moto_guzzi_loopframe_wheel_bearing_adjustment_shimming_set_up.html

 :1: :1: :1:

Check the bearing, it's easy to do. Follow the link for the instructions.

Good luck,
Tom

[marc-s]

Here I am again, sorry for the delay. First: thanks for all the inputs and the help, really appreciate it!

I measured play at the rim because it was a quick job just to confirm that there is something going on. I measured again at the hub today and have found out that play when wiggling at the rear end of the wheel is minimal. but when wiggling at the bottom side where the wheel touches the ground is around 0.4-0.5mm measured at the hub. It seems that play is not equal in all directions. There is also some vertical play but I might be mistaken.

I will open the hub and take a look at the bearing. If there is no obvious bearing failure am I right to assume that the problem is incorrect shimming? Or could there be another reason for my symptoms? I'm asking so I can order the parts before I'm on vacation... then I'll have everything ready for when I'm back.

Here a short clip: https://www.dropbox.com/s/sbo8e3knp39lou2/2016-04-21%2014.45.34.mp4?dl=0

[v7john]

I've just done the same job on my V7Sport which has the same bearing arrangement. I started with 0.16mm play. Re-shimming got it to 0.04mm. 0.05mm was my target.

https://racingrhino.wordpress.com/2016/03/11/rear-wheel-bearings-10-mar-2016/

You've got much more play than I started with and, if the play is not the same in all directions, it may be that there is some bearing damage.

[Tom H]

Rear wheel side to side movement can be caused by two things normally, the swing arm bearings worn or loose or damaged, the wheel bearings worn  or loose or damaged.

Swing arm, grab the swing arm and try to wiggle it side to side at the axle and look at the gap at the bearings and see if that changes. Might even grab the tire at top and bottom and push top in and out and see if the swing arm moves.

Wheel bearings, follow the link and follow the instructions. This sounds like your issue. With the seals removed and the tapered roller bearings out, clean and inspect the bearing and the race for damage. If not damaged, you "normally" can reuse them. Stainless shims can be had at McMaster Carr, or a bearing shop and the like, or your Guzzi dealer should have a selection. I'll try to find my shims and see what thickness they are.

Edit: The shims are 20mm ID X 28mm OD X .1mm thick.

Hope this helps,
Tom

[marc-s]

Opened the hub some minutes ago, roughly cleaned the bearings and took a look at everything. bearings (outer races and rollers) look fine: no marks, no scratches, no pitting, nothing. Shimming is set to 2.2mm (1.2mm + 2mm shim). The only thing I noticed was play in the outer race on the right bearing. See video: https://www.dropbox.com/s/91d9dtwhu547w9l/2016-04-22%2012.57.44.mp4?dl=0

It does rotate and move up and down. But I cannot feel any lateral movement (did not measure). I can't slide it out all the way, but will try with some heat. From what I see the mating surface does not look overly used to me (aka it looks clean and unscuffed). But I'll have to take a proper look once the race is out.