Tank Slapper

[Canadian FJR]

Here's the situation;

Avon Storms 40 F / 42 R

Both bags full

Fuel cell full

Tank bag full

I cannot release the pressure off my bars, if I try to remove both hands - wicked head shake (The kind that will hurt you).

Avon Storms 40 F / 42 R

No bags

No tank bag

Fuel cell empty

I can lift my hands and no problems, no head shake - none.

So I realize that it must have something to do with the additional weight but should I be firming up the rear shock, front or both? I'm just assuming that this will solve the problem. Any helpful suggestions would be appreciated.

Canadian FJR

 

[rushes]

You don't have that ugly big assed European tank bag on there do ya?

 

[Ignacio]

Depends on more variable I can think of. You doing 20 or 120 when you try this?

If you're doing say 40 mph or less in these two scenarios then it likely is a weight distribution issue. You might then try the lean forward, lean backward thing to see if the oscillation frequency or severity changes.

If you're doing higher speeds that the sidebags, cell, and other accessories are much more critical parts of airflow...then it could easily be an aerodynamics issue.

 

[wfooshee]

How much tire wear at the moment? Worn evenly, no cupping? I notice some increased head shake on my bike as I get into the life of the front tire.

As for pressure suggestions, I have no clue. I'd think higher for the loaded bike, but I'm no expert on tire pressures vs. wear vs. behavior under load.

 

[Reaper]

I had the same problem with the Storms. It's a weight distribution thing. I solved it by useing PRII's.

 

[03HiYoSilver]

Canadian,

I had the same problem and Firmed up Both my Front & Rear Suspension Settings and the problem went away.

 

[Fred W]

Here's the situation;
Avon Storms 40 F / 42 R

Both bags full

Fuel cell full

Tank bag full

I cannot release the pressure off my bars, if I try to remove both hands - wicked head shake (The kind that will hurt you).

Avon Storms 40 F / 42 R

No bags

No tank bag

Fuel cell empty

I can lift my hands and no problems, no head shake - none.

So I realize that it must have something to do with the additional weight but should I be firming up the rear shock, front or both? I'm just assuming that this will solve the problem. Any helpful suggestions would be appreciated.

Canadian FJR

I'm no expert either, though I don't want you to share that info with my wife or co-workers.

The biggest weight item you mentioned, and the furthest offset from the bikes center of gravity, is most likely the fuel cell. Try some more experimentation like this:

Avon Storms 40 F / 42 R

Both bags full

Fuel cell empty

Tank bag full

 

[fjrob1300]

I've got just the thing! When I'm all loaded up and haulen ass on my John Deere I add a couple of these to keep the front end down!

 

[mdisher]

You still running stock suspension? If so I think it's a weight distribution problem and you're getting your geometry all out of whack.

I'm no expert either but have experienced this on my previous bike. When I overloaded the ZX11 (with Givi's and top case) on a trip it tended to have very violent head shake. I loved that bike but got tired of trying to make it something it wasn't.

Oh and ditch those Storms too.

 

[Bulldog9]

+1 on the weight issue, I think too much on the rear tire, I bet if you run as you were - the fuel cell, your shake goes away. If it does then try the cell 1/4 1/2 etc. I've never seen the reason for a fuel cell, I'm happy to stretch a bit every 250 miles :yahoo:

Suspension may play a part as well, but YMMV

 

[Fred W]

Well, the purpose of the fuel cell (to extend time between fill-ups) is generally a requirement for LD rallying, and for use in the open west where there are some places with huge distances between fuel stations. So that makes it somewhat of a non-negotiable item for the folks that have them. So if the fuel cell being empty (all else loaded) makes the shake go away, next try the cell full and the trunk removed. That may be a compromise that you can live with, at least until you switch tires.

 

[Canadian FJR]

fjrob1300 - Just one question, will I still be able to wheelie with one of these John Deere weights up front?

For everyone else, thanks for the feedback. Tires are not worn (yet), Ohlins and Eiback suspension and this situation was noticed first at highway speeds but will happend at any speed. I have tried shifting my body weight but didn't seem to make a difference. I think that I need to try some suspension changes and go from there.

(I still love the Storms, the harder you ride the better they work)

Thanks,

Canadian FJR

 

[fjrob1300]

Hey Scott I think you could wheelie a Boss Hoss ...lol.

 

[roger dodger]

The Avons have had a checkered past. Some friends on a Concours swore off of them as this headshake and lake of confidence issues perpetuated. I loved my Avons (until my crash)(not the tires fault) and am thinking Storms or PR2's next time around. Even Avon has admitted to some manufacturing variables in some tires (not balanced/ high spot/ thick spot) and taken them back when asked.