Rear end wobble

Hey all

I've got something really strange going on, when i am leaning around a corner at over 70mph and over, the backend starts to wobble.

I first noticed it on a road trip when I had some luggage on the back, so at the next stop handed over the lugagge to a van that was following in our convoy, same thing occured.

something to mention is just that week before i had akras fitted at the dealer and asked them to setup the suspension to the hardest setting so i could see how i got on.

Anyhow when we got to our destination I had the manual with me and set all the suspension settings back to standard, its a piece of cake as i am sure you are all aware, so i am sure i didn't get it wrong.

So i still have this issue and it sucks as you sort of lose confidence in the bike and makes my ride shit.

The SD is fairly new to me so looking for some suggestions are where to start looking?

Please help.

Cloonster

Is you axle nut on tight?

Is your rear wheel straighton the measuring guage?

Did this problem occur immediatly after the dealer fitted the Akras and screwed with the suspension?

And just to confirm, you read the manual correctly and set all adjusters in the correct direction and also set the front forks back to standard at the same time?

Nut it tight, just had new tyres fitted today as it goes.

What do you line up the chain adjusters with as i see no markings, i see the notches/lines on the adjusters as in the left and right pics below but dont see a line on the swingarm to match them up.

Am i being daft?

Left



Right

Bash
yeah the first time i noticed it was after the akra install along with the sus change.

And yep change the suspension back all in the right way. Had my brother in law read the manaul too to make sure i was doing it right.

i should point out that in a straight line absolutely no problem at all, its only when you are really leaning over on a corner at speed. it just starts all of a sudden and you shit yourself.

Extreeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeem close up

Those notches need to be the same both sides they are your measuring guage.

Sounds like suspesion issues though, dont see how fitting akras could cause any issues.

thats the thing superdan, what do those notches line up to on the swingarm?

Not sure if its the light but the lower pic of the two (as you can see 3 notches protruding from swingarm) so looks further back than the top i.e. slightly out of balance.

Your axle blocks are installed the wrong way round (unless you have a 40T rear sprocket?)

The engraved lines you see on the tops of the axle blocks should line up with the Semi circular cut outs in the lower part of the swing arm where the blocks slide back an forth!

Im leaning towards a suspension problem here though!

Have you adjusted your rear pre-load/sag since removing the standard silencers?

Now that you mention it i had a 40t rear installed at the same time as the akras and hard sus setup by the dealer.

This is what i have set it back to.... let me know if i am missing sag...

fork
compression damping standard 15 clicks
rebound damping 15 clicks
spring preload 5 turns

Shock absorber
compression damping low speed 20 clicks
compression damping high speed 1.5 turns
rebound damping 12 clicks


I have read previously that some folk dont rely on the adjusters and actually take a measurement on both and left right, any idea where from and to?

reading on a bit more i haven't touched the rear preload at all.

There is a great bike garage close by (who race bikes) who i have spoken to before about doing my suspension for me based on my weight etc.

They quoted me £60 to do the whole setup, you reckon thats maybe an option for me?

WellI go by the markings and never had an issue.

You sure you turned all the clickers the right way? (can remember if its anti or clockwise)

yep all clockwise until no further and then anti clockwise by number of clicks specified in the manual

Try adding a few clicks of rear rebound dampening... Should sort the rear out

if you had the rear wheel off for a sprocket change at the same time i'll bet dollars to donuts the moron who put the wheel back in screwed it up, get it on a stand and check for side play while installed and try and turn it, does it turn freely? any strange noises or rubbing/grinding feeling through your hand as you turn it? i set my adjuster length by using a steel rule against the front edge of the slot where the adjusting thread winds into the swingarm against the front of the adjusting block, that's much more accurate than using the cast in "guides" which are usually way off. if all that is ok take the wheel out and check the wheel bearings, all three so remove the sprocket carrier, over torqueing the rear axle can dislodge a wheel bearing race, any notchiness or play and they need to be replaced.

paul.

you don't say that you adjusted the shock preload. That would definitely have an effect on handling.

This may or may not be suspension related. Op stated that he had new tyres installed as well.

Few questions:

Do the wobbles start when you encounter bumps in the road or are they present when the road surface is smooth?

What kind of tyres did you have mounted up? What pressures are you running?

How much do you weigh?

Stock bike? What year, model?

A slight misalignment in the rear will not cause a wobble. It will cause the bike to turn quicker in one direction than the other. you'll also wear out your chain and sprockets faster. To align rear do as a previous poster and I do, measure the distance from the surface which the locknut torques up against to the leading edge of the chain adjuster block. This is the only acurate way to set rear wheel alignment other than measuring from the swing arm pivot to the axel.

John

From a quick squint at your settings the rear shock compression looks very soft. I run 10 back from full hard at 13.9stone fully kitted. It does read like something slack or well out though.

Thanks for all the replies, will get cracking on with all the suggestions and post back.

Holy shit Viking that is one impressive wheelie!!

Make sure he has not accidentally lost one of your wheel spacers on the axle too.

Sorted, I think!

Redid the the shock high speed compression damping and the beast is hugging corners at pace.

Makes me laugh, what did I change?

"high speed compression damping"

What was my problem?

High speed wobble on the rear.

Quite plainly in the writing, however I choose to make it complicated

Anyhow thanks folks, happy man again.

On another note.

Whilst out riding yesterday, came across an "A" road that was being resurfaced. In a nutshell bike was full on tar specs. Spent three hours cleaning on my return.

fooked off however in the disregard that the council has for peoples prides and joy. Rather just close the road .

Fortunately had a can of muck off degreaser in the garage, worked a treat.

@ bash, cheers

High speed damping isn't about speed of the bike though, more the speed of the shock moving. Normal cornering is taken care of by low speed and bumps in the road ect are taken care of by high speed. Or that's my understanding of it anyway.