After dropping the rear preload to something in the ballpark of sane (it had been fully cranked when I got the bike), the bike exhibited a nervous headshake above 70 mph or so. I cranked some preload back in and some of the headshake subsided. I'm mostly attributing it to an imbalance between the front and rear suspension probably aggravated by cupped tires, etc. The forks are *stiff* and sit tall. Anything over 70 mph in dirty air, and the bike starts its dance. A little spooky, but not scary. Until today. A friend and I were droning out on the highway to some off-road stuff. I decided to kick down the passenger pegs and stretch out a little. The little headshake suddenly got bigger and bigger and BIGGER. This was similar to the death weave we've all felt in the sand, but I was on pavement, in traffic, at 65 mph. Oh dear god. The modest shift in my weight was, clearly, the catalyst. I thought I was going down. Time to go through the bike and solve this.
Had the same thing happen on another bike and it turned out to be the rear spring. Apparently the previous owner weighed somewhere around 140lbs geared up and had re-sprung the bike. I ended up changing the spring to one for my weight (180lbs). Reset the sag, ect... Problem solved. Prior to that it scared the doo-doo out of me a couple of times. Kinda like trying to hi-speed corner a Kawi H2... I haven't had this issue on my 610 because it seems the rear is sprung about correct for my weight. I set the static sag and then the race sag a little high and things were ok. Also check your fork height in the trees, if the silver caps are flush then it might be too high. The Marzochi's have lines on them to measure how far you move them up or down. Try dropping down 1 line (3mm) on the forks.
I have the same issue at 65 mph on my 08 610 started out as a SM and I converted it to a TE not out of control but unnerving . It seemed to be worse when it was a SM and much more apparent when I am in traffic. I tried moving the forks to the second line and it helped some but not 100%, I noticed if I move my weight forward it makes a little difference. Looking for help also Dan L
My bike starts exhibits a very slight headshake at 85+ when it is windy, but it is completely manageable. I think it is just a matter of a 300lb bike with a large front fender. If I sit forward it is slightly better, but I have to go into a full tuck to get above 85 without needing a downhill or long road. I can very very easily cause headshake by pushing on the bars at speed, and the bike corrects itself as it should. For the record I'm 6'4" 200lbs, so I add a great deal of wind resistance. The suspension is dampening is set up as per the manual, I haven't messed with the preload though eyeballed it is 2/3 of the way down, but have dropped the forks one line.
My 610 is starting to try to do a little headshake and I'm quite sure it is because of a cupped MT21 front and a new D606 rear.
Tires makes a big difference and so does balanceing. My 610 has seen the higher side of 100 many times with very little nervousness. Make sure that the spokes are tight and that the wheel is true, check tire pressure, look for tire runout (flat spots or nasty cupping), have tires balanced and check that the headstock is properly set. At this point I'd like to make a shameless plug for the Motosportz steering damper. It makes a hugh difference off road and a noticeable improvement on pavement.
Fabed up a Scotts steering damper on my TE610. I took it off my 07 TE 250 that I sold. It seems to have taken out the head shake on the freeway. See what you think, I will make a new tank bolt from 4130 with a built in washer this week,
Personally I like the idea although there are some challenges with it. The stock bolt is a bit small so it would likely need to be replaced with a heavier one. If you made a insert that dropped into the slot on the tank you might be able to fit two smaller bolts in there and use one of them as a post mount but it would be a custom type set up and I doubt that anyone could make that arrangement as a off the shelf set up.
I taped it out from 6mm to 8mm, when I make the new bolt I will michine in a washer like the orginal tank had.
That sounds like it would probably work. There isn't a tremendous amount of torque on it but since it is a piece of you're steering I feel better with a beefier arrangement. There was a guy on ADV that did what you are doing, the pieces looked really clean and then we didn't hear from him for months. Turns out that he was just busy with other things but some of us were a little worried.
I would stay away from the steering damper, because it's just going to mask the problem. Check your tire pressure, head set bearings, and then start adding rear rebound to your shock. If your shock is moving too fast and bouncing under hard acceleration, that movement can transfer to the front and cause some wiggle. Try adding 3 or 4 clicks at first and don't go for any extreme settings.
Yes, make sure that the suspension is set up properly and that there are no other issues that should be dealt with before adding a damper. Dampers are great but they shouldn't be used to mask a problem.
My 09 now doing the same. Have had the bike about 2 weeks. The head shake is severe and usually happens if I ride near the crown in the road at 65+. Checked tire balance and steering head play - both are good. Will look at suspension setup. Maybe preload in back has the rear too high?
Quick update on my bike: step 1... New tires Steering head bearings given a cursory check. No notchiness or freeplay detected. Fork oil changed and level adjusted. Rear shock preload sort of set. Tried forks up and down in triple clamps. Fiddled with suspension settings and different air pressure. And the problem was still there albeit not quite as bad. It feels like a deceleration headshake. If I move my weight (190 lbs) to the far back of the bike, I can get up over 80 mph easily. Step 2... Pulled the bike apart, checking all of the bearings that might remotely play a part (not that many). They were all fine though a few needed a little grease. Decided to check the steering head bearings more thoroughly. The ring nut (nut below the top triple clamp) was only finger tight! There was *no* preload on them at all. Put some preload on them, but not much. Bike is now markedly more stable though there's still a slight problem. Forks flush at the top. Rear sag is impossible to get right as that spring is wayyyyyyyyy too heavy for me. Step 3... Suspension is now with LT-racing getting reworked. Should have the bits and pieces back next week.
Interesting find on the ring nut. Will check that too. Never have had a bike so sensitive to setup. Hopefully I can find a long-term solution.
I took a look at mine a few week back and found the same thing. I tightened them up a bit and now the bike rides better at higher speeds. I don't get the deth weave until I get up past 75mph in traffic and none at all on the road by myself. I look foward to hear what the shock rework dose for ya.
I take it that you have checked the wheels for runout, spoke tension and wheel bearings, right? To me the front wheel bearings are a little wimpy and a little sloppyness,,,,,,,, well, you know.
Wheels seem fine. Spoke tension is ok, wheels are true, and bearings seem tight. But, as is often the case with me, a second look wouldn't be bad.
