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Motorcycle News (UK) - - Garage -

Q How can I leave a weave be­hind?

Al­though in most re­spects my Yamaha XSR900 is a great bike with a ter­rific mo­tor, the han­dling gets a bit in­ter­est­ing when you re­ally push on. The bike weaves and shakes its head when things get hot. What hap­pens is that, at speeds above 90mph, the bike starts to weave and, par­tic­u­larly if the road is at all un­even, the bars start to shake and give the im­pres­sion that if I don’t back off I’ll get a proper tankslap­per. I don’t take a pil­lion and I weigh around 12-and-a-half stone. I should say that I have clicked the re­bound damp­ing right back to soften the ride, but the prob­lem was ob­vi­ous be­fore I did that. Grant Nai­smith, email

An­swered by Gareth A Evans, Re­ac­tive Sus­pen­sion A wob­ble is the steered mass (forks and front wheel as­sem­bly) os­cil­lat­ing around the steer­ing pivot (head­stock). But, as you say, you’ve got a weave which is the rest of the chas­sis os­cil­lat­ing around the steer­ing pivot. A wob­ble is nor­mally a fast os­cil­la­tion at low speed. A weave is a slower os­cil­la­tion at higher speeds. I would imag­ine it’s be­ing caused by what you might diplo­mat­i­cally call a less than sat­is­fac­tory shock per­for­mance. Here’s a link to a Dun­lop ‘ed­u­ca­tional’ film from the ar­chives that shows the dif­fer­ence, and how rider weight and rid­ing po­si­tion can make a dif­fer­ence: https://youtu. BE/Z3OQTUke2s.

In the first in­stance, you need to go back up on the re­bound to tighten up the shock’s re­sponse. Some­times jack­ing up the preload on the back end can get rid of a weave. If it’s sit­ting low at the rear that has the ef­fect of giv­ing more trail so there’s ex­ces­sive self­cen­tring which sets up a weave. In the end, you are go­ing to need a bet­ter-per­form­ing shock.

Tight­en­ing up XSR900’S rear shock re­sponse is first step

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