bad weave

[wozza35]

hi can anyone point me in the right direction as to what could be causing a really bad weave on my xt at about 75mph ,would it be the more off road biased tyres that are fitted?it seems fine up tp this speed and if you take your hands off the handlebars it goes straight
any ideas?
cheers warren

[Gregorius]

Weave or wobble?? Generally what causes high speed weave is knackered headstock bearings. Have you tried turning the bars from side to side with the wheel off the ground (not at 75mph though!!) ?? If the bearings are shagged then you'll feel the bars 'self-centre' into the detents caused by the bearings banging into the race. A lot of off-road work or hard wheelie landings can cause this. If they're bad enough then it can have the same effect as winding a steering damper up fully.

Other things to look at are wheel bearings , tyre condition and pressure, spoke tension, wheel alignment .... just to give you something to do this weekend lol...

Might help - might be bollocks!!
#
Best of luck - Greg

[Laromonster]

An XT or any other off road bike with high front fender and hanguards will be aerodynamically challenged, sit forwards almost on the tank, pull slightly back on the bars and hope for the best

[mollydog]

Warren,
A high speed weave is very very common on 600cc dual sport bikes.
Mostly they do it right from new. Change of tires might help but I doubt it.
Greg has pointed you to a few things to check, although I doubt head bearings will cure this problem.

I've had the exact weave you describe, at the same speed on the following bikes.
XL600 Honda, (near new)
KLR650 (when brand new)
XR650-L (from new)
DR650 (brand new, 2005 model....weave started at 90mph)

Various things that might help:
1. relax your grip on the bars at speed
2. crank up rear pre-load a bit
3. raise fork tube up in triple clamps about half inch (lowers front of bike)
4. Fit a steering damper.
5. Snug up Steering head bearing...but only slightly.

As mentioned, the front fender contributes some to this but is NOT the sole
cause of high speed weave. Sometimes fitting a mini sheild can help too.

Fiddle around some, don't worry. Nothing wrong with bike.

Patrick

[electric!sheep]

Try riding at 35-45mph, loosen your grip on the bars, and give one end a nice punch. If the bike wants to go into a tank-slapper, you need to tighten up your steering stem nut. When properly adjusted it should wobble then straighten out.

[wozza35]

thanks for all the replies guys, looks like i got a bit of investigating to do but at least i have an idea where to look