when adding ,say,a topbox etc,to the bike ive noticed a pronounced wobble at 45-50 mph(accelerating and decelerating thru that area),bit like a tank slapper feeling thru the bars.
i think there is this wobble even without weight on the rear,albeit very faint but guess i sort of ignored it/got used to it in the past.
everything is in good nick on the bike and wondered if anyone else had this and sussed what it was?.

 

I had a similar problem..after adding {45litres} topbox but never at the higher speed, usually at around30 -40 km/h and only when I released the handlebars - off the throttle .. I took it off and there was no wobble whatsoever .. I was told that thereisn't much to do about it just keepingthe hands on the bars .. {not that I wouldn't but sometimes you need to..and the feeling of that wobblemakes me worried ..I only put it on when I ride two up for a long distance otherwise I am happy with the Ventura bag sitting on a pillion's seat ..
I hope it helps a bit ..

 

it does seem a bit strange this,have just asked on another forum and quite a few have this wobble.
i cant beleive "its just one of those things" being its a class production bike and has been around a long time.
will have to investigate further i think,none of my other bikes do it and theyre all around the same era and none have dampers etc fitted.
i need to investigate what causes are for "tank slapping" first and why adding wieght/moving centre of balance rearward would affect it all.
mite be "hacksaw" time

 

Hi all. Just out of interest do you all ride solo? If you do the when you put this box on change the setting on the rear damper as if you are carrying a pillion rider. See if this helps.



[sm=bounceybounce.gif]

 

Don't know if I understand correctly the 'tank slapping'but as far as the adding weight goes the wobble was present even if the top case was empty withno pillion, no panniers ..perhaps the aerodynamic and the size/shape of that topbox caused it ..there is no wobble with a pillion+ the big ventura bag behind the tail light ..

 

Then you've solved your problem. Aerodynamics and the box are not compatable, so whats happening is the wind hitting the box face on and pushing the bike around. When your carrying pillions the face of the box is now covered so the wind goes straight passed. Don't know what is the easy way to cure this except to change the shape of the box.



[sm=bounceybounce.gif]

 

hi,no isnt wind etc,tried it with just a bag of tools on the rack,still does it.
ive never carried a pillion so all this solo stuff.
ive also got my shock set up quite solid so it doesnt wallow as on normal settings,in fact its nice and tight now on those bumpy bends.
i have a bridgestone on the front which was on it when i bought it and is down to 2mm approx,so will change it for a matching conti and see if it helps.
will also re-oil the front damping as think its probably original oil in there.
just checked runout on the front wheel rim and is running true.will perhaps check the disc rotors l8r.
ps: my idea of tankslap is when the bars repeatedly flick left n rite forcibly on their own.

 

What are your tyre pressures.
Are your tyres Scalloped?
Are the bearings ok?
Rear Swingwarm bearings?
Fork oil levels?

 

My F-L has front end wobble at 45-50mph. Can't feel it when holding the bars, but if I take my hands off the bars, there's a noticeable wobble (about two inches back and forth). I believe it's something to do with the flat spot in the outer edge of the front rim - no doubt caused by going up a kerb or something.... At all other speeds it's fine. Might be worth checking how round your front wheel is.

 

i beleive my pressures are 34lb front and 38 rear,no sign of scalloping,in fact the front is very even wear all round.
bearings all seem fine,same for swingarm(just noticed inner rear brake pad worn more than outer so caliper appears to be sticking)
fork oil levels yet to be checked,fork spring/sitting height looks even.
im going to whip the wheel off and examine closely as that would appear to be a good possible,no telling what its been thru in 16yrs/230000 miles.
thanks all,appreciate your input