Hi
This afternoon i took my xb12s for a small run to test new fuel map. Everything was ok till 140-150 km/h(87-93 mph), when i got big shimmy. Road was flat highway no turns, thanks god i have steering damper, but it was scary . Every time i close to 85mph it happens again and again. Question is what is wrong with the bike?? Fore most of the time i use bike in city, but month ago i rode 95-100 mph with no problem.
Thanks for any suggestion.

Sure someone will correct me if I am wrong, but I would check my Tyre pressures first then wheel and headstock bearings. Swing arm bearings too.
How many miles has the bike done?
Have you the suspension to hard on the front etc!

Nate.

Tire pressure OK, suspension setting hard, bike has 5000 km (3000 miles), front wheel bearing seem to look OK, rest of bearings i will check, only modification i done last time was magura SX handle bar, which is more wide than original one.

Hmmm my sx had it's front to hard when I got it, it only had to hit a mouse turd to start shaking it's head. I softened the pre load off , the compression damping and the rebound to very soft and then over a couple of weeks started adding untill it would just start shaking it's head in a bend on a bump etc. Never had a problem again. I found the previous owner and asked why he sold it. He said it scared him, I could see why untill I got it handling!

Had some wide bars on a sv650 once, had to remove them the bike just would not handle the same, don't read would not handle, just not to my liking.

Good luck.
Nate.

Well Problem solved. I change handle bar to stock one and did a test drive. 100, 110 mph and everything OK. Pity because i really like magura's look and rider position. I still can't understand why it was so big difference. Magura SX is wilder for about 4 cm (1.6 in) each site, lower, and more straight. Rizoma handle bar is bit similar to Magura but with Rizoma handling is OK.

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FUBAR pilot

You only need two bikes in life-an S1 and a Multistrada!

Unlike the Australians, you need to loosen the fuck up!

If you could ride faster a month ago and now it does it all the time, then you could try switching the bars back and riding without looking at the speedo so closely. If you expect it to happen from 85 and you grip tighter because of it, then the cause might be, as Beef suggests, the nut connecting the bars to the seat.

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Good in straight lines
2001 X1 "The Tart's Handbag"
2001 FZS1000 "The Fridge"

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08 Specialized Langster

Non-standard bars can easily provoke unbalance in the front, esp. if they are wider / higher / straighter.
I never understood the urge of many bike-owners to replace perfectly fine and specifically designed handle-bars as an "improvement" to the bike. After-market ones are usually only available in two or three styles to "suit" hundreds of bike-models, what can you possibly expect?

I have wide bars on mine and a lose grip and relaxed shoulders is the way forward, take a look at your tyre pressures as well just in case

<<< click

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"With square conduct, level steps, and upright intentions ..”

Yamaha bars are made out of cheese and swept back too far. Renthal 758s are significantly stronger and they are the right angle for my hands. I expect them to be more comfortable, more resilient and to look better, they are and the do.

What's not to understand?

Alternative viewpoint, I never understand why people accept what the manufacturer gives them without considering that the paltry sum of £25 can do wonders for an eight grand bike.

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Good in straight lines
2001 X1 "The Tart's Handbag"
2001 FZS1000 "The Fridge"

i had mine snakin at the same speed and above . adjusted top suspension tops they now show 4 grooves that is to say i adjusted them clockwise and adj rebound top and bottom big improvement . take notes of settings before you adjust anything then you can always go back to were you started / check your rear dampimg at same time and make sure it not to soft when you bounce on it . i finished off by just tweeking front rebound a bit at a time and road testing and got there in the end . push down on yer forks using brake it should only go down and return once and not bounce back down again .hope that doesent sound to complicated .

4 got to say mine is a xb12r so i do have a bit of a fairing

If I recall correctly, UK (& Euro) spec s1's came with narrower (and lower?) handlebars than did US ones to make them more suitable for high speed use on motorways.