Tank Slapper / Handling Issues.

[Pixter]

Very very nearly had a nasty off yesterday

I've had the 650 single for about 2 weeks now and I have noticed a couple of handling niggles, but just put that down to my previous bike being a 1150GS which handles brilliantly with awesome suspension.

Yesterday, whilst overtaking a line of slow moving traffic on a wet road, I rode over some white chevron lines on the road (the type that you can drive on if clear). Well, it was clear in the opposite direction so I was accelerating gently when the whole bike started to wobble like an angry bull. Within a second I was having a world class tank slapper and thought I was going to have a personal introduction to the tarmac very soon. However, backing off the throttle and leaning my weight forward did the trick and she smoothed out enough to stay upright. I got away with that one!

So now my thoughts have turned to why that happened, I've performed similar manoeuvres on all sorts of other bikes without any issues at all, so why did the little GS want to spit me off? The previous owner has replaced the rear shock with a non-adjustable Hagon shock (which feels quite stiff), could that be the root of the problem? I don't want another "moment" like that, my gusset can't handle any more "fear"!

I have owned an F650GS Dakar in the past and that gave me no such problems, in fact, for hooning around shit covered country lanes, the Dakar was the best bike I've had.

Any advice will be gratefully accepted!

 

[Timolgra]

Check your headstock bearings they're prone to failure

 

[Dansin]

You could also check tyre pressures and condition as well as fork oil height.

 

[Deleted account 181015003]

Did you have luggage on if so it could be a weight distribution problem

 

[(RIP) MScotts]

+1 regards testing the headstock for excessive bearing play and checking tyre pressures...

What size is your rear tyre; i.e. the standard is 130/80-17. I'm sure I've read somewhere that having a larger rear tyre than the standard (i.e. 140/80-17) can lead to this sort of behavour; could be well wrong though...?

 

[Myke Rocks]

I know this might sound stupid, but

Check that the front wheel is clamped properly into the forks with everything properly torqued up.
I know it sounds ridiculous, but, as a teenager, a bike I had was prone to tank slappers, and this was the cause.
Myke

 

[Schtum]

I rode over some white chevron lines on the road (the type that you can drive on if clear).

That's something of a moot point. The law was changed a few years back. It now says that you can cross chevron boxes which have broken white line edging "if it is safe and necessary to do so". You might want to look for legal precedents as to what constitutes "necessary to do so".

I'm not saying for a moment that it's something I don't do but I think it helps to be aware of the facts.