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Howdy all: Last week I took a trip to Oshkosh WI for the fly-in. While heading up US 41 I got behind a dump truck. My 1000K6 began to wobble slightly until I pulled out and passed the truck. I run with a Cee Bailey screen and Madstad bracket. The windscreen is mounted on the lowest setting and tilted all the way back.

Now wind turbulence behind trucks (or even pickups and minivans) in nothing new, but this wobble was. Anyone else experience such?? Is there a way to "fix" the issue?? or should I just use a bit more throttle??
 

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I am running the standard screen and bracket. However, I am adding the madstad tonight.

I just finished a 1400 mile trip on the DL650. I would get a little wobble behind trucks some times. I was running speeds up to 95MPH.

First, the wobble is slight. All I would do if I felt it would be to get out of the trucks burble. (the area of turbulence behind the truck).

To reduce the wobble, I would also hug the tank with my knees and duck my head a little. Also, a little increase/change in speed and no more wobble.

The main thing is don't just sit there. Change position, speed up or slow down and it will go away.
 

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Seems like if I relax on the grips a little it helps.
 

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Don't run behind trucks! :D Just tell the cop it's a safety issue. :D
 

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In general, lowering the front of the bike/raising the fork tubes about half an inch or so can help with the way the bike is affected when passing trucks. I don't know if it would solve your particular issue with that combination of windscreen, etc but it does make my bike feel better in this type of situation.

..Tom
 

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A fork brace helps a lot for this and cross winds. Also lowering the fork tubes helps. I've done both and really like the results. Now I hope to add Sonic springs and see what improvement that makes.
 

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In general, lowering the front of the bike/raising the fork tubes about half an inch or so can help with the way the bike is affected when passing trucks. I don't know if it would solve your particular issue with that combination of windscreen, etc but it does make my bike feel better in this type of situation.

..Tom

Absolutely Right Tom!! I got my bike about a month ago and I had read on this forum about raising the fork tubes. It seemd that a LOT of the guys do it but I put it off. I finally got around to doing it last Saturday and the difference is unbelievable! My bike used to be a slug in turns and it took a concerted effort to drive with any speed at all going around corners. It's like a different bike now though. I raised mine exactly 3/4" and was very, very careful to be sure that they were both exactly even. It's a lot more stable now and doesn't try to remain tracking straight when I turn it. 3/4" might speed up the steering a little too much for some but given my past roadracing experience, I'm a lot more comfortable with a quicker steering bike then a slower one. I bought it to take on trips and certianly not to race around or I would have bought something else but it sure is a lot more enjoyable for me to ride now. I'm recomend to anyone who has a Vee to raise those tubes and you won't be disappointed.

Jeff
 

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I tried for exactly half an inch but my forks kept wanting to settle at .54 of an inch. After fighting with it for half and hour I gave in and tightened it at .54".

..Tom

..I raised mine exactly 3/4" and was very, very careful to be sure that they were both exactly even.

Jeff
 

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In general, lowering the front of the bike/raising the fork tubes about half an inch or so can help with the way the bike is affected when passing trucks.
+1 for that. It helps a ton. As also mentioned, a fork brace makes a world of difference.
 

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Good suggestions all. One of the biggest items I've found to make a difference is... TIRES!! I had some real scares with my K5 650 on the original rubber. I made it better with the forks raised, and I have a Givi and Madstad, which helped, AND I run tank panniers sometimes which seems to help as well. I ran ME880 Metzlers for about 12k miles, (biased ply) and the stability was MUCH improved in dirty or side wind. I've put on Distanzia's recently, and although I like the tires, they are just a bit .... "touchy"?... behind trucks. Not near as stable as the ME880's, that's for sure.

I'm not sure what will be my next tire as these have less than 1000 miles on these. Who knows, it might be time for a different bike before they wear out anyway.

Anyway, the point I'm trying to make is that the tires are probably the biggest factor, but not the ONLY factor.
 

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The turbulance behind a large truck effects everything, especially bikes since they are so light weight. I feel turbulance it in a full size van.

Does adjusting the fork really going to help since it's a short time you want to be in that position. Since raising the forks quickens the steering, isn't that effecting it worse v. being at a more stable longer rake setting.

I'm still waiting for my Super Brace. Race Tech Suspension and springs are next. Yes they have fork springs now. Probably shock springs as well.

Best to just get-out-the-way.
 

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Just raised forks 1/2"

I have just got through test driving my DL650K6 on the interstate at speeds up to 90mph after just having raised the forks 1/2". Here are my thoughts.

The bike is more stable at high speeds. The reason, I believe, is because the tri-collar's 'grab' on the forks is at a lower lever, thus eliminating some of the bend and consequential resonance that occurs when the front-end recovers from bumps. It's similar to the effect that a superbrace has. This is not to say that it would cause the same improvement as a superbrace, but it is noticable, and I now do not intend to buy a superbrace. It's more stable on rough roads at lower speeds, and for the same reasons. My front end pre-load is set at 3 disk showing and the rear pre-load is set at 3 also as this Article recommends.

As for steering responsiveness, the greatest difference I noticed was when doing a tight U-turn into a parking lot. The steering responded more quickly, which makes sense since the rake has been reduced. Anyone who has ever ridden a chopper should be able to understand why a larger and longer rake makes the steering less responsive. The front wheel has to track a longer arc in its relationship to the frame to turn the bike. Overall, I think the bike handled better, but not a huge difference.

For me, the most desirable improvement is the improvement in the front suspensions responsiveness to rough terrain at low speed and increased stablility at high speed. I was surprised that only a 1/2" raising of the forks would make any noticable difference, but it did. I intend to leave it this way. Here is a link to some good step-by-step instructions with photos if you want to try it. Didn't take but about 1/2 hour and that includes dragging my tools out and putting them back.
 
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