S4 Ohlins SD154 problem

[jerry]

Originally Posted by Kato

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

yes mate thats what I do ,, tried riding through it , not fun at all, but im good at sensing it so just back off a tad but I hate not solving issues ,,

[jerry]

Originally Posted by 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?

tried it all Gazza , had this bike for 18 years now ,, bars are flat, no fairing , lowered forks 10mm very good suspension with full adjustment both ends ,tried every possible geometry etc 2 mirrors, tried every possible body position including flat on tank,

only thing I never tried is a steering damper , which was a reccomended fix by numerous people on Older monsters flightiness and wobles at high speed ,

I have been stubborn as new fitted a damper to any bike i rode in the past , solved them other ways , and my 750 monster is stable at 115mph ish but of course the S4 has 50hp more and the front end always feels lighter than any other bike I have ever ridden in last 50 years ,, My modern Z900 feels very solid and planted at 130+ mph but its not as agile a missile as The S4

[jerry]

im back in UK and just got an email from Ohlins dealer in Bangkok seems Ohlins may have assembled some damper wrong and stamped them with wrong code ,, but its all older stock ???

I will try to pick up a damper set while in Europe but im not paying £500+ spo looking at other makes, hyperpro, Ktech etc they seem around £300 a set

[jerry]

Brook suspension can get me an OHLINS kit for my S4 with mountings for £426 which is cheaper than Hyperpro also say 6 months minimum wait as Htperpo say they dont have the correct mounting kit.
, Ktech dont have mounting kit for S4 so thats out

So look like I will order the Ohlins from Brook suspension but i cant fit it until i go back to Thailand in October ,,,

I now have all the oils seals for the clutch 12x08x3 and other bits I need for then too.

[jerry]

Just spoke with my Ohlins guy in Thailand ,, he says that the problem with wrong size of the Damper he supplied me with was down to Corruption with Fedex and Thai customs which is not uncommon ,they replaced the genuine ones with fakes !!! When I was running a Bike business in Thailand in the past we had many issues with Fedex and customs replacing genuine HD parts from USA with Chinese fakes , or just confiscating orders for themselves ,, including legally imported items ...

We were told by FEDEX headoffice in USA not to import items via fedex Thailand , and to use DHL???

nothing ever changes there ..One of my stolen bikes a 1200 sportster I imported with 20 other bikes that were passed ok is brazenly being ridden around by a customs officer since 2006 ....