S4 Ohlins SD154 problem

[jerry]

i have obtained an ohlins SD154 steering damper kit for S4/S4R monster but there is no way it fits the frame to forks as its stoke is 140mm its not long enough ?????????? i reckon it would need a 170mm stroke to be able to turn the handlebar ???

im perplexed ...
I want it or an alternative as S4 always headshakes at speeds above 120mph and everything is spot on .

[slob]

are you sure it’s an SD154 (side mount) and not the more usual sideways on the top yoke jobbie?

[350TSS]

Jacking the rear suspension up about 5mm would help with the headshakes. With the dreadful design of handlebars on the S4 it is not possible to drop the yokes on the stanchions

[Darren69]

Originally Posted by 350TSS

Jacking the rear suspension up about 5mm would help with the headshakes. With the dreadful design of handlebars on the S4 it is not possible to drop the yokes on the stanchions

This is a good thing to do on any of the early Monsters, they're too rear biased and with the S4 power can get a bit wild up front! I did that with my S4 Foggy and put clip ons so you can drop the forks too if needed but didn't find that necessary. Steering damper does help too.

[Kato]

https://www.ohlins.eu/en/products/mo.../sd-154--4521/

[jerry]

Originally Posted by 350TSS

Jacking the rear suspension up about 5mm would help with the headshakes. With the dreadful design of handlebars on the S4 it is not possible to drop the yokes on the stanchions

suspension on rear is Ohlins and up 7mm , bars are renthals with yoshimura yokes and 996 forks with Ktech internals dropped 20mm due to 996 forks being 10mm longer than original showas so 10mm down on front end bike handles beautifully et all speeds very agile and tracks corners like a leech

bike still headshakes at 120mph and has always done that

[jerry]

Originally Posted by slob

are you sure it’s an SD154 (side mount) and not the more usual sideways on the top yoke jobbie?

its the side mount with all the correct fittings but it aint long enough for sure

[slob]

the spec on kato’s link says 140mm stroke, so that’s the fork leg moving nearly 3” back and the same forward lock to lock, in old money, which sounds close but about right

[stopintime]

https://motowheels.com/i-8576662-ohl...-s2r-s4rs.html

Now with pictures of it mounted

[jerry]

Originally Posted by stopintime

https://motowheels.com/i-8576662-ohl...-s2r-s4rs.html

Now with pictures of it mounted

yes thats it but , im not getting lock to lock turning in that configuration

I may try a top bar mounted one instead and send this one back to Ohlins

[Kato]

Open this link

https://www.ohlins.eu/en/products/mo.../sd-154--4521/

Scroll down to bottom of the page and there is the mounting instructions with spec and a full kit list and an owners manual

[jerry]

Kato I have those instructions but its clear that the damper is too short , mounted as per intructions I cannot turn bars . i am gong back to Ohlins dealer to see what the issue is ,,he says I may need different unit ????

Im also looking at the DP one for sale on UK Monsters by John D but as I have modified yokes and bars it may not fit also heard a lot of negative about DP Gubbinelli kit ????

prefer Ohlins i have a lot of their stuff already shocks , fork internals etc on several bikes and the side mount unit will have no problems with change of bars and yoshimura triple tree.

[jerry]

Problem solved ,, the SD154 is not an SD154 its been wrongly marked at factory its only 110mm stroke,, my Ohlins dealer is a good bloke and he is shocked , when I took it back he measured it , I had just assumed it was correct but its only 110mm stroke ????? no wonder it does not work , he has refunded me as he does not have another in stock ,and he will chase up Ohlines about it ?????

So im looking again but he had an exceptional deal as it had been sitting on his shelf for a while and other suppliers are asking £400+ for similar dampers ,, I am tight on money right now so will be looking for a bargain over next few months as \i wont be back in Thailand until late October .

But I really need a damper for the S4 its a must ,I have owned this bike 18 years and nothing has cured the headshakes above 120mph and believe me I have done everything you can think of

[Kato]

Well clearly the cure for headshake is to stop at 119mph problem solved

[Mr Gazza]

+1 for Kato's suggestion, or roll off even earlier than that.

In the late 70's early 80's I rode a lot of contemporary Bonnies and Tigers back to back.
They would nearly all start a Dutch roll at exactly 98mph, not a shake or dangerous speed wobble as such, but with varying intensity depending on how quickly you got there, passenger present, road surface and so on. It would settle if you pushed through it. (But not much left @ 98 to be honest!)
I noticed that the UK spec bikes with flat bars did not do this and attributed the phenomenon to aerodynamics. The US or export bars were quite high, so I think it was something to do with the wind rolling off one side or other of the torso alternatively. Much as a flag will flutter in the wind, or a loose jacket?
In your case it might be something to do with a headlamp fairing or screen if you have one, or maybe a mirror on one side only? I imagine you already have lowish bars?
Have you tried just bending your elbows and tucking in a bit when the wobble starts, or preferably just before?