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Old 11-03-2007, 02:18 PM   #1
bluesman OP
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Weaving...advice please?

Hope to find some wisdom with my question...
Here is the problem. I got DR800, my friend got DR650, other got Aprillia Pegaso 650. Their bikes converted to supermoto, mine not...
Every time I'd go over 130-140 kmph bike starts to weave a bit, same with my friends bikes. They tried mine - nothing like that, they also have none of that problem on their bikes. They both about 6.4 - real tall, one is hevier than me, one is same. I am just way shorter, like 5.6 and all bikes seem to do that with me. Does not happen when I ride with my wife as passenger, thou front wheel even less loaded then...
Bikes I tried absolutely different, like supermoto converted dr650SE, supermoto-converted but with touch of touring and cut off front plastics Pegaso 650 water-cooled (same motor as on F650), and then my 184-190 kg dry elephant of thumper DR800....
None of my other bikes have same behaviour, but then I rode only road bikes before and still keep some of them....any advice - hint?
Again, bikes do not fall or go into no-control, they just kinda feel a bit unstable and weave somewhere from 140 kmph and all the way up to 165 kmph (102 mph?) on normal highway.

bluesman screwed with this post 11-03-2007 at 03:01 PM
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Old 11-03-2007, 05:33 PM   #2
Lone Rider
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Tires would be the usual guess, but raise your front end off the ground, using the skidplate or somewhere under the motor, and check the steering head bearings with no load on the front of the bike.

Other than that, maybe weight distribution and front to rear wheel alignment.
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Old 11-03-2007, 06:12 PM   #3
Thraan
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Heavier riders on your bike have no problem? And no problem 2 up? But problem solo?

Sounds like your don't have the rear shock adjusted for your body weight, not enough sag.
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Old 11-03-2007, 06:13 PM   #4
slipknot
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weave

Steering head bearings too tight?
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Old 11-03-2007, 06:14 PM   #5
daltonzach
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differences in weight make a large difference. I am 6'5" and weigh a svelt 300 pounds. My 86 xl600 is straight as an arrow with just me on it. When I put on the side boxes and tent and sleeping bag it gets a bit of a wobble at about 70 mph. more like kida twitchy than wobble. I think it is just subtle flex in the frame that does it cuz i checked everything that moves or pivots and all is tight. I have been playing with air pressures in the tires and front forks and everything i can think of. It is of great possibility that your lack of weight is the cause of what you are feeling. I definetly think adjusting air pressure in front tires will make the difference so would a steering stabilizer. I considered this but i don't ride much over 65 mph fully loaded. that's my .02 worth
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Old 11-03-2007, 07:14 PM   #6
potatoho
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I agree with Thraan. Even a mm difference can solve the headshake. Dropping the forks in the trees (thus raising the front) about 1 mm, or increasing the rear sag.
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Old 11-03-2007, 07:15 PM   #7
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I had the super speed wobbles on the KLR. Seems that it was some delicate conglomeration of velocity, tire balance, road condition, rear rack loading, rear shock preload, as well as a loose radiator fairing.

Scary shit though, when it gets bad at 80 mph.
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Old 11-04-2007, 12:37 AM   #8
bluesman OP
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thank you all - I appreciate your answers guys, I think I am going to try some changes in suspension settings. What really amazed me and my friends is that me on their bike = weave, and them on my bike = stability, actually at some moment it turned into laughter as they said I made their bikes scared to weave :)
Obviously that excludes technical issues with my bike, another thing - one of guys almost 1 feet taller than me but same or even less weight (he is really skinny guy) and he ridest supermoto DR650, which weaved under me too. Other guy is much heavier and feet taller, rides Aprillia Pegaso that weaved with me on board but not with him! To add insult to injury - both their bikes run 17" supermoto wheels and sticky road tires, while on mine wheel is 21" front and So, how the hell I managed to find perfect imbalance to upset all 3 so different bikes is pure magic
Will play with suspension/pressure settings then. Thank you all again
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Old 11-04-2007, 12:55 AM   #9
Max Kool
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By any chance, you aren't holding onto the bars too firm?
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Old 11-04-2007, 01:03 AM   #10
bluesman OP
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nope, I thought about it - tried to deliberately let handlebar go completely loose....same effect. In fact I used to "feather touch" on the bars since I mostly rode naked sport-roadster bikes before and sporty bikes later (my second bike now is vtr superhawk)...
And when I ride with my wife as passenger - no weave on my bike. Perhaps I should try to sit on the tank to see if front load helps, it's just I am a bit scared to do it on highway when bike behaving like that
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Old 11-04-2007, 01:37 AM   #11
Thraan
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My KLR used to wobble at high speed on the highway. Upping the tire pressure helped a bit, but not much. Adding a fork brace helped a bit more, but not enough. Checking and tightening the steering bearings helped a lot, but not completely. Sitting a bit further back fixed it good.

"Nuts on the tank" is great for off road, for slow speed, for corners, but for superslab, I slide back a bit to weight the rear a little more. I think it changes the steering head angle (rake? castor? not sure of the bike term for that) in relation to the road. That's my theory anyway.

And now back to my regularly scheduled boozing.

Oh and your tall skinny friend might be sitting further back just naturally because of longer limbs.

Good luck! Ride safe! Write ride reports!
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Old 11-04-2007, 01:39 AM   #12
Thraan
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And it's better to adjust the rear suspension sag properly, than to sit awkwardly. Listen to Potatoho. As an Irishman, I can assure you that potatoes never lie!
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Old 11-04-2007, 01:42 AM   #13
Thraan
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And for your hometown brew bluesman!
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Old 11-04-2007, 04:37 AM   #14
bluesman OP
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Quote:
Originally Posted by Thraan
And for your hometown brew bluesman!
Cheers, I fully agree :) Let me just grab another bottle...
BTW - if any of you guys passing by - welcome, I'll let you taste Hoegaarden from the tap - that's whole lot better than bottled


Thanks for advices on my problem - I will actually try all suggestion starting with changing riding position, perhaps I got too drawn to "offroadeness" of this bike and really overdoing sitting more to front...
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Old 11-04-2007, 05:37 AM   #15
Kommando
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I'd guess it's the weight being too far forward that affects the geometry too. You can actually lengthen the wheelbase of the bike by shifting weight slightly further back.
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