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Discussion Starter · #1 ·
Hi All,

Just bought a used 03 FJR, it has the panniers and a Givi rack, there is no weaving of the bike with the panniers, but when I put on my 48 litre Givi top case, the bike starts to weave from about 80mph upwards, when riding solo. I see from other posts that a couple of others have noticed this, has anyone managed to find a cure (apart from not using the top case)? Are there any suspension settings that can be tweaked etc?

Thanks,

Tim.
 

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It's an odd issue & one that I don't have an answer to (no bloody good me) but I wonder why the weaving only affects some riders?? I have never had a problem with my Givi case either solo of two up.
 

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Discussion Starter · #3 ·
I should also add that both tyres have been changed from BT020 to Conti RA's and the bike has done approx 6000 miles. I did notice the weaving with the BT020 tyres also.

Tim.
 

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Discussion Starter · #4 ·
Tony said:
It's an odd issue & one that I don't have an answer to (no bloody good me) but I wonder why the weaving only affects some riders?? I have never had a problem with my Givi case either solo of two up.
Hi Tony,

Are you able to provide your suspension settings, as this may be a starting point, which model year is your bike? I also have the Yamaha touring screen fitted and the weaving appears to be less pronounced when the screen is in the fully down position, although I need to do some more riding to confirm this.

Tim.
 

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If you do a search on all the times this has been discussed you'll find that it happens when a rider is solo, and conditions allow the airflow to 'close' behind the rider and then get 'forced apart' again by the topbox. Any of the following can change this airflow pattern:
Pillion behind the rider - the airflow obviously can't close behind the rider;
Change in screen height/size/angle of attack - changes airflow pattern
Having the side cases on - also changes the airflow behind the rider as they force more air up and create a turbulence that also stops the airflow 'closing' behind the rider;
Lie flat on the tank - this can increase the weaving as you create two more distinct 'disruption' points - you, and the topbox
Big broad shouldered guys don't notice the weaving as much; and
The angle of the wind from the front can also affect it.

Good luck if you think you can find a permanent cure, when riding solo. My suggestion - find a pillion who is prepared to fill the gap - no weaving at all, just an occasional thump on the helmet at triple digit speeds.
 

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@Stonetown,
Don’t worry it's the air passing around your body catching on the box, if you were 2up it wouldn’t happen! It depends on the size of the box mines a 46ltr will weave a little around 85mph but not as bad as it did. Try stiffening up the rear shock as it mite help
 

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They all do it. Its an aerodynamic issue caused by the airflow between the rider and the top box. It never gets bad enough to cause problems, but if you a desperate for a cure then fit a passenger.
 

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So I think we are all agreed on that one! :crylarf:
 

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Just one more agreement...


BUT I also got a cheap and simple solution (well it works for me anyway).

I store my waterproofs rolled up under a cargo net behind me, as it fills up (some) of the gap it fully removes the weaving.

And, before you ask, if its raining I will lower my speed so weaving isn't a problem then.

:mrgreen:
 

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Discussion Starter · #10 ·
david1300 said:
If you do a search on all the times this has been discussed you'll find that it happens when a rider is solo, and conditions allow the airflow to 'close' behind the rider and then get 'forced apart' again by the topbox. My suggestion - find a pillion who is prepared to fill the gap - no weaving at all, just an occasional thump on the helmet at triple digit speeds.
I tried a search on weaving, but it didn't seem to pull out anything very relevent, any suggestions for a better search term?

OK, so here are my choices so far:

A blow-up pillion (could be interesting)
I design some kind of airflow disrupter or wings or something, takes time and money (both of which I'm short on)
I pump iron to broaden my already broad shoulders.
Buy a Yamaha top-case, does this suffer with the same problem?
Buy a pillion seat case, any suggestions?
Change the screen, to what?
Ride with the screen in the lowered position, but I like the adjustable screen, it's one reason why I bought the bike!
Change the bike, but I've only just bought it and I like it!

Tim.
 

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Tony is the only one without this problem, so you may want to try his cure.....Put on 5 stone and push the airflow out wider, and reduce the gap between arse and Topbox..


*No offence intended*.. :mrgreen:
 

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Stonetown - you need to seach on the old sites for more info on this which has been discussed a number of times. But the answers are as above.

I remember bagman did a photo-cum-graphic of the airflow behind the rider.....not very scientific but illustrated the point.
 

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Top Box Weaving

On my last trip to Death Valley, I had a similar issue with my duffle bag strapped to the flat plexiglass rack I have bolted to the rear. With the bag strapped perpendicular to travel the weave would start around 90mph and amplify above the century mark. Thinking on this over a beer at Stovepipe Wells, me thinks turn the bag longitudelnly(sp). This technique reduced the issue dramatically.
Re: the top box, I recommend a rudder bolted to the top of the box. Think Boeing 747.

In San Diego, I'm going for a ride on the Classic FJR.
BAGSTR
 

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Tony is the only one without this problem, so you may want to try his cure.....Put on 5 stone and push the airflow out wider, and reduce the gap between arse and Topbox..
Of course it may just be that my riding is so erratic all of the time a bit of weave goes un-noticed? :mrgreen:
 

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If you don't carry a pillion at all, what I would try is to re-mount the top box closer to the front of the bike. To do this, you would probably have to drill new mounting holes in the carrier plate for the top box. The top box would then partially obstruct access to the rear seat, so you couldn't carry a pillion, but I think it would reduce the weaving problem both from an aerodynamic, and from a weight placement point of view.
 

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I ride a 2003 FJR with 49000 Km on it now.

I have had a GIVI rack and E360 mounted and Bridgestone BT54 tyres for years now without a weave at slow to 200 Kph speeds.

I just fitted Mich Pilot Roads and it now weaves????? Pressures 41 - 42 as read here. I am going to try going back to 38 – 40.

I cut CalSci holes in a spare STD screen and the weave seems same if not worse. No push in back though.

The Mich’s feel very smooth/soft so it may be characteristic of the tyres?
 

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I have a Calsci screen fitted and OEM Top Box on 06 model, no problems with weave at all.

For info I had Ultraseal installed and had severe balancing problems with the front tyre only, that I have never experienced on any other bike fitted with Ultraseal....

Nova :wink:
 
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