Sidecar on a V7–(Potential) Side Effects *Pics Included

[Dirk_S]

Thought it might be worthwhile sharing some observations that I’ve collected in the year+ riding with the sidecars attached to the Dirty Goose.

May 2022
During the first attempt at the Mid Atlantic Backcountry Discovery Route, 2 days in and following the fun rock garden mountain climb just outside Poe Paddy’s campground in Pennsylvania, I found myself lacking some power at higher speeds on pavement. Thought perhaps it might be the clutch slipping. I aborted the remainder of the trip while I waited for a replacement clutch, pushrod, bearings, seal, etc.

In the process of stripping the bike down to prepare for the replacement job, I discovered the driveshaft was cracked at the u-joint and nearly seized. While the speed issue turned out to not be clutch-related (cleaning out the dirty fuel filter turned out to be the cheaper, quicker fix), the cracked driveshaft had my interest piqued. At the time, the bike had 30k miles on it. Could this crack have happened simply from normal wear from 30,000 miles accumulated with some occasional, mildly aggressive off-pavement riding? Could it be due to the slightly longer rear shocks that were installed a couple years ago to offer a tad more ground clearance? Could the sidecar be causing enough torque stress to the driveshaft that caused the joint to crack? Or, perhaps this is a buffet, with all three contributing to the failure?

September 2022
Riding back home from a vintage bike show with a friend in the sidecar, and the bike breaks down on me. Many know the story by now—I starved the bike of oil. Engine rebuild and I’m now officially treating the V7 like a Ural in terms of maintenance monitoring—halving my service intervals, giving it more breaks when riding it at speed for longer periods of time, monitoring the oil level much more often, and cutting down the freeway time.

December 2023
When putting the motor back into the bike, it’s time to install the swingarm. Once again the supposedly simple process of screwing the pivot pins into the gearbox recesses has me confused, because I think I have too much gap between the pivot tab on the swingarm and the bearing recess—at least 6mm on both sides. Perhaps I’m once again not doing it right, or, as I suspect, the lateral stresses of sidecar steering are causing the swingarm to flex, and twist. This is further evidenced by the bushings in the rear shocks working themselves out of the holes. Will monitor.

June 2023
Having returned from the second MABDR attempt with many more miles accumulated this time, I start addressing some of the little niggles and concerns that popped up before and during the trip—mostly tightening bolts, checking bearings, etc.

I decide to check out the swingarm. I have a spare (black), bought off eBay, waiting to compare with and replace this one if needed

Current swingarm (bare), with ~6,000 miles of sidecar use, has indeed stretched at the pivots, by about 1/8”, if we’re to assume (a) the current swingarm and the gently used eBay swingarm (black) were once the same exact distance apart, and (b) the ebay swingarm’s pivot distance is still to spec:









Swingarm has been swapped, measurements recorded, we’ll see where we’re at in a year.

Driveshaft was next up for inspection, once again with an eBay spare in hand to be compared with and potentially replace the current one.

Pleased to see the u-joint is in fine condition, just as smooth as the eBay’s. Transmission-side splines look great, too:






But the aft end of the driveshaft is a different story: the external splines of the shaft and the mated internal splines of the coupler are damaged, as seen in the pics. The spring initially appeared to also be slightly compressed compared to the replacement one, but upon further inspection, they seem to be equal:










Guess I should be happy that these are the wear items, and that Guzzi has used this drive shaft for over 30 years. I imagine another thousand miles or so, I’d be full-on slipping.

I notice that if I place the internal stop plate located inside the coupler in front of the snap ring as the parts diagram shows, the driveshaft’s splines poke out a couple mm:





But if I place the plate behind the snap ring, the driveshaft splines are fully recessed within the coupler, and there appears to be no counter visual on the final drive’s splines. I unfortunately didn’t take note the exact placement of everything when I pulled it apart, but I’ve decided to stick the plate behind the snap ring, hoping that the extra 2mm might help strengthen the spline mating, which may or may not help anything.

Driveshaft, coupler, and spring all replaced with the ebay counterparts. Looking forward to seeing what it’s like in another 4,000 miles.

I should also probably / definitely address those shock bushings, too. And maybe not lift the chair as much. Or, just stock up on used swingarms and driveshafts.

[bigbikerrick]

Looking at this swing arm, It appears to me, a smallblock Guzzi may not be the best choice as a sidecar tug.I am not sure if even a properly designed fixture,or subframe would have helped with the lateral forces in this situation.
Rick.

[Dirk_S]

Looking at this swing arm, It appears to me, a smallblock Guzzi may not be the best choice as a sidecar tug.I am not sure if even a properly designed fixture,or subframe would have helped with the lateral forces in this situation.

I see what you’re saying. Looking at this R80/7 in my driveway slowly coming to life, the swing arm pivot pins for both bikes are actually very similar in appearance. But the swing-arm mounting differs—BMW’s swing-arm mounts on the inside of the frame, constraining the pivot mount area within boundaries during lateral stress, whereas the small block swing-arm mounts on the outside of the gearbox, relying on its own rigidity, the pivot bearing, and bearing seat on the inside to maintain integrity.

Not ready to give up yet. Let’s see what 4-6,000 more miles shows up.

[mechanicsavant]

Personally, I think you’re asking way too much from a V7 .I’ve got a MkII & a V7/850 & knowing a few “Hack” enthusiasts . They wouldn’t dream of using such a bike for sidecar duty. Long ago large Guzzi frames were rated for sidecar use . As were a few BMW chassis. Checking with some /7 folks to prevent issues . The side stressors on a “Rig “ can be quite substantial as you’re discovering. Best of luck !

[GearheadGrrrl]

Mounting swingarms to transmissions always looked questionable to me. The manufacturers are always looking for ways to cut costs by reducing the number of parts in a bike, and they like the idea of losing half or all of the bikes frame. In 99% of applications that works fine, but in applications like hacks, heavily loaded police bikes, etc. they're pushing their luck. One way around the problem is to find a builder who will create a subframe to manage the loads of a sidecar, but sadly many of those builders have retired and the creations of the remaining ones aren't easy or cheap to obtain.

[spmoto]

I agree with the above opinions. Based upon the evidence you've provided; it appears that you're really pushing your luck. The heavily stressed and thus worn components are just what is "obvious". What else is lurking and waiting to fail, potentially catastrophically? It's your butt, but isn't "sensible" motorcycling risky enough?
You might want to seek out some advice from Rob Dentico (RadGuzzi). He is a wealth of knowledge on all things Guzzi and Guzzi-hacks.
Steve

[Dirk_S]

I prefer to exhaust the options and potential solutions. Besides—it’s too easy to give up.

When I first talked of the idea of adding a sidecar to the V7, there were multiple detractors. Not one, if I recall, mentioned the swingarm mounting. Out of all the concerns—trail, driveshaft, oil capacity, air-cooled, stress-membered engine, etc., this one offers the most concern IMO, at least that’s the current mindset.

That said, I’ve been looking at modifying the subframe anyway in order to gain some much needed ground clearance and lift the mounts and allow the sidecar wheel lead to be pulled farther back, so maybe my modified subframe can incorporate some swingarm-bracing structure. I think it’s possible for sure.

[Bulldog9]

Following this with interest, though Dirk's adventures make me cringe 

I'm super impressed and surprised that no one is giving him Kudos for taking a sidecar rig on the MABDR, and more so a V7ii side car rig. A little medium framed/44hp mild street cruiser on what can be a challenging set of roads for most ADV bikes.

We also need to note that he has but (cough cough) 200lb passengers in his side car. So before we start talking about the V7 not be up to hauling a side car, lets consider how well this rig has handled pretty abusive conditions and weights. After all, If Dirk had a 200lb pillion sitting behind him (try not to gaaag) and 400lbs of rider/passenger on a largely off road conditions does anyone think the swingarm or splines would have done any better?  I think not.

I don't have much experience with the inner width of the swing arm pivot on the V7, but as they are all shimmed and centered, the 6mm difference between the e-bay donor and old swing arm are suspect. I'd be concerned about stress fractures on the swing arm and rounded out or worn pivot bearings and races.

As for the triveshaft spline and coupler, there IS a right and wrong way to assemble, and one way leaves the splins only 1/2 to 2/3 seated in the coupler as Dirk highlighted.

This V7 is IMNSHO holding up quite well given some pretty abusive (extreme) conditions. Throw a 200lb passenger with a 200lb rider and beat the willies out of it, and see what breaks on any bike. Overall, I'm impressed with how the little V7 has handled the assigned tasks. Too bad it got starved of oil for the mid tour intervention, it would have been interesting to see how it handled the use over an extended time and I hope Dirk Keeps it up.

.  I WILL eventually add a hack to a bike in the near future, but rather than doing a URAL imitation on the Stornello TT, it will likely be on the Convert for grandkid/dog duty, THOUGH the V7 is not off the table. I just won't have a 200lb monster in my side car.............. 

Thanks for sharing Dirk, I'd love to see the MABDR pics. Retirement is around the corner, and I get my life back.............

[Frenchfrog]

My God...the damage on those splines is shocking.
What surprises me is that these days most sidecar users don't seem to change the gearing when putting a chair on.Back in the day we never kept any of our British bikes on solo gearing when fitting sidecars . Of course , adjusting the gearing on a Guzzi small bloc is not that simple as you have to change. the primary gearing in the gearbox and maybe the rear wheel diameter.
I've had and have several small blocs and the only one I'd consider remotly capable gearing wise to have as a sidecar outfit would be my NTX 650 which has a 5000 cc  gearbox as standard.That gives it bags of pull low down.

[Dirk_S]

@Bulldog, you’re either a fan of the underdog, or a toxic enabler ;) MABDR trip recap will indeed arrive, but with so much on the plate, it may be a spell before posted.

@Frenchfrog, funny you mention the NTX. I’ve recently begun diving into the TT and NTX history. I’ve always wanted my V7 to be more like an R80 G/S, and longer forks with leading axle are the next item on the to-do list—actually, not too much left after that. I figured that not only can I get higher ground clearance with the longer front suspension and bigger wheel, but the leading axle can also help lessen the 4.6” of trail that cause the heavy steering.

I also recently read that, as you pointed out, the gearing was different on the NTX; however, I suppose if it’s not in the final drive but instead in the primary gears, then that potential modification can be crossed out. Actually—the gearing difference is the primary reason why eventually I’d like to get ahold of a V9 gearbox and motor, or mate the gear box to a V7III engine and change the top end. That’s down the road, though.

I think it’s important, when considering the concerns that have popped up, I’m often learning empirically—I’m like a poor man’s Edison—I grow a little wiser by learning what NOT to do, and in this sidecar journey, I see these issues and consider I may have goofed something on my end before I call the experiment dead…like the poor but noble sap that I am who has faith in the scientific method to eventually figure this crap out.

[Frenchfrog]

I feel you pain Dirk !
So dig into history a bit more and you'll see in a hidden ,obscure place the existence of the 650 TT Baja bikes...smallblocks made to order by the competition dept at mandello .Only 17 of these were made and the relevant thing to your project is that they replaced the normal small bloc swinging arm and drive box with a big bloc one which pivots on a modified frame rather than on the gearbox castings. Lots of work to do this and maybe out of your budget but it would rectify the bending swinging arm issue nicely .The UJ will be infinitly more durable too as when small blocks were first ran in the paris dakar in the early 80's this was also a problem .

[Alfetta]

It may be possible to affix a "Watts-link" to your swingarm to negate (or greatly reduce) the transverse forces the rear wheel applies to the swingarm bearings, as you drift that hack.



If you can find the room in the diagram above pivots "A" are fixed to the frame and thus pivot "C" can only move vertically. red rectangles are the S.A. spars.

[jhem68]

The pics from the Iowa rally show that Hannigan has no problem with attaching one of its sidecars to a 2017 v7 lll Special. Too bad there wasn't a more detailed look at the mounting.



The owner of the rig (Paul), did express some concerns about the durability of the splines.