Givi V46 Affects Handling

[kmev]

I installed a Givi V46 on a Shad rear rack on my 2012, and following the installation the handling seemed squirrely, like the front tire was following rain grooves when there where no rain grooves. It happened consistently at normal highway speeds on concrete and asphalt over about  2,500 miles. Today, I removed the box for a 250 mile ride and all the squirreliness was gone - it was rock solid the entire trip. 

My two previous bikes - a BMW K75s and an FJ-09 - both had top boxes for a combined 100,000 miles and the boxes did not affect handling. I am perplexed by this. It affects handling whether empty or lightly loaded. I do have a fairly new Ohlins adjustable rear shock. Sag is where it should be. Is it possible that adjusting shock length either longer or shorter could solve this? Any other suggestions other than leaving the box off? I REALLY like top boxes. 

 

[RossKean]

I have a Givi V46 on a Givi 357 rack on my 2011.  I have never noticed any similar misbehavior at any speed that I would attribute to the topbox.

(I have a Penske rear shock and Traxxion AK20 forks.)

 

[BigOgre]

I sorta remember this being talked about once or twice before.  Try strapping a tailbag or something onto the passenger seat and see if you notice any difference. 

 

[escapefjrtist]

From what inmates have posted, squirrelly handling attributed to trunks / top boxes typically happens at, shall we say, elevated speeds. I've run OE Yamaha, V46s & V47s for years now and haven't noticed any odd behaviors until into triple digits (closed course!) testing. As an experiment, add some preload and a couple clicks of rebound dampening.

Adding...GP kitted forks and Penske shock.

~G

 

[roger dodger]

Honda was warning folks decades ago about a 'high speed wobble' due to the bubble of air over a larger top box.  I've gone very fast with no issues.  

Try firmer suspension, air up the tires, tighten the steering head , and ride with a bag on the rear seat to deflect bad air.  I often ride with bags or trunk, but usually not both. 

 

[FJR Flyer]

Got the V46 with the Givi rack. No issues experienced above the tonne.

 

[kmev]

Thanks for the advice. I will try riding with a bag in front of the top case - that should help isolate the cause. Then try some suspension adjustments. 

 

[saread]

There's been a lot of chat over the years about head shake with hands off the bars causes and solutions. I think we've all come to the conclusion that it's just a thing and if we don't take our hands off the bars it's not an issue.  I can say that I never noticed that phenomenon until I put on a V46.  I've never really tried to determine if that was the actual cause. But it has always made sense to me that a big box on the back would, at some level, affect the front end.  Not enough of deal to make me take off the box though.  I have heard that the bike is very stable at some impressive velocities with the box on.

 

[Old Guy]

When traveling I carry a V56 Givi on mine.  The first time I took off with it on the bike I noticed a twitchy feeling in the front, but I got used to it in a few miles and did a 3000 mile trip to the Rockies with no problems.  I run locally without it  and still travel with it, and I don't even notice a difference now.  

I do run the rear shock on hard with the case on and soft with it off.  

 

[Geezer]

Do you normally carry some weight in the box or ride with it empty? I never had an issue with mine, but I always had a few things in there that weighed a few pounds.

 

[Bounce]

Loading is important. I put a leather jacket in the trunk of a GL1200 Wing and, with the other things already in there, that heavy jacket was enough to unload the front wheel and cause a slow oscillation while going down the interstate. I was on a BBG so couldn't take the time for an extra stop. When I laid down on the bed at the end of the ride, it felt like I was on a boat.

Tail packs/trunks tend to be high and behind the back axle; both bad for loading up. Take the heavier stuff and put it as low and central to the bike as you can. Put bulky (but light) stuff in the trunk or save it for a helmet when parked.

 

[Steel_Gin]

I noticed the same issue when I ride with a top case, it just feels a touch loose.  Unfortunately I haven't been on a long trip since I got it so I can't say if it goes away with weight in it.  I notice it the most on windy days.

 

[kmev]

I usually ride with it empty or with a light load. Occasionally, I'll throw a couple dozen ears of sweet corn or a bag or two of groceries in there. When I am traveling, it holds a sleeping bag and a few other light items. I never really paid much attention to handling differences with different weights in the box, as I never suspected it was the top case until recently. A few days ago I did 50 miles out with a 50 liter bag strapped to the rear seat in front of the box, and 50 miles back with no bag. Having the bag seemed to make an improvement handling, but I need to do a bit more testing to be certain - it was rather windy that day. 

 

[Geezer]

Your weight, size, and shape may also make a difference in how much wind reaches the front of the top box. Another variable may be the windscreen you use and what position you keep it in.

 

[Bounce]

I noticed the same issue when I ride with a top case, it just feels a touch loose.  Unfortunately I haven't been on a long trip since I got it so I can't say if it goes away with weight in it.  I notice it the most on windy days.

Weight will only help is it's loaded in a way to NOT unload the front wheel. That means bulky light stuff in the trunk. Tools, heavier gear, etc. should go as low and forward of the rear axle as possible. Filling the gap between the rider and the front of the trunk can also help when it's an issue of "wind resistance" instead of weight.

 

[Old Guy]

It's all rather counterintuitive to me.  I use the box because my laptop won't go into either of the side cases.  I've not weighed it loaded in a while, but I suspect it's overloaded when I carry it.  Yet, no problems at all.  I can even let go of the bars with the cruise on and hold the bike in line by just shifting my weight around.  I can tell it's there when corniering, but no wiggle or wobble.  I can even ride fairly spiritedly with it in place.  I can ride more spiritedly with it and the panniers off, but that's to be fully expected. 

It's interesting how different other people's experiences are.  I guess I'm just one of the lucky ones.

 

[SwollenRaccoon]

Lots of good info already. My two cents...

   I have ridden with the top case (Yamaha factory case) many times. Like previously stated, put your heavy stuff in the saddlebags, and make sure everything is mechanically sound on your bike. I have also ridden two-up with the case in place.

   From MY experience (no offense to anyone else, I'm just stating what MY bike does, and why I think it does it), I think it's an airflow/aerodynamics issue, more than weight placement. Solo, nothing on the passenger seat, and moving at elevated speeds (why, in Bob's name would you do otherwise on an FJR?), I notice a vagueness and slight wandering of the front end, as if, as stated above, there were invisible rain grooves. Nothing frightening, although it's easy to feel like you're being warned of impending doom. Windscreen position did seem to have a small effect on the weaving, but a pack strapped on the passenger seat (not a heavy pack) seemed to lessen the problem considerably. I do know that with the screen in its higher positions, it forces a downdraft down the back of my neck, and I think that same wind flow, regardless of screen height, comes down somewhere behind the pilot and in front of the top case, which would tend to cause more drag in back of the bike, lightening the front end. A passenger totally eliminates the vagueness, but one could argue that it's the extra weight toward the back. But that argument would seem counterintuitive, since more weight on the back would probably mean less weight on the front, at least proportionally.

   Sorry for the long diatribe. It's just what I think is happening, and we all know that it (my opinion) doesn't mean ****.

  Ride hard, boys and girls.

 

[Brodie]

...  I can even let go of the bars with the cruise on and hold the bike in line by just shifting my weight around.  I can tell it's there when corniering, but no wiggle or wobble.  I can even ride fairly spiritedly with it in place ...

That’s pretty much been my experience on all three of my FJRs through the years. A good part of my saddle time is with both hands on the gas tank, and body steering down the road. The hands don’t get numb if they don’t touch the grips.  Cruise control does have its benefits. 
 

One note, all three bikes have had the headset bearings upgraded with the roller bearings early on. Before the upgrade they all had the YAMAWOBBLE upon deceleration between 45 to 30 when riding no hands. All it took was a light hold on the grips to quell the oscillations. 
 

One other silly thing to check – Make sure your subframe is intact. It took the weight of my ancient laptop and leather case and stuff in my V46, mounted to the plastic OEM rack, and riding on a washboard road to blow out my die-cast subframe back in 2010. That’s a lot of mass cantilevered back there when the road gets rough. 
 

Good luck with it. 
 

Brodie

 

[Bounce]

Does anyone remember Yamaha Corp published advice that, if running a trunk, remove the bags? It was for the aerodynamic drag issue above.