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Shaking over 50MPH?

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I searched quite a bit but couldn't find anything so I was hoping one of you guys might have the answer to this. I just bought this bike (02 400s) so I don't know much about when any sort of services have been done but here is what I am experiencing.

The bike has Kenda 270s on it when I rode it, I noticed the front end would start to shake when I got over 40MPH or so. It's not shaking like a head shake (side to side) but more like up and down (like I was holding a jackhammer). I noticed that these wheels have rim locks on them and there were no weights so I stuck the wheel on the balancing stand and got it balanced pretty good (not perfect but pretty close). The shake is still there after balancing. Between that and tightening the front suspension up a little, its better, but still starts to get pretty noticeable at about 50 MPH now and much worse as you speed up.

I also stuck a dial indicator on the rim and spun it - it is straight as an arrow. To the eye, it seems like the tire itself has a bit of a wobble when i put the front end in the air and spin the tire but maybe my eyes are deceiving me. I don't feel any play in the neck bearings and the suspension doesn't seem sloppy so I'm thinking its the tires even though they look fairly new. If I thought for sure it was the tires I might have some different ones put on but I'm just not sure.

Oh, and this is my first DS.

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OK, I'll do it the way Eddie recommends from now on. Just to make it clear to me and everyone else, I should:

- push in the axle all the way

- tighten the right pinch bolts (the ones by the speedo gizmo)

- tighten the axle nut fully (31.5 lb/ft)

- tighten the left pinch bolts (the ones by the brake disc)

Is this correct?

yes,the full clamp force will be applied to the spacer and drive.it wont be able to move.

^ installed like this? many posts on head shake, front vibration about speedo position/front wheel installation.

without spending to much $, assuming tire is good, pressure is good, front end is good, since it sounds like you've done what should have "fixed" it, try removing rim loc's and putting in a new tube, re-balance, test ride.

MT21 front on mine, no rim loc's, no issues, way past 50mph ...

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Hmmm. Not Exactly. I went by the manual so i will have to try that. I put the wheel on the balancing stand and gave it a good spin and I can see a pretty good wobble so I think something is up with the tire. I will run it by the dealer in the morning and get it checked out.

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Hmmm. Not Exactly. I went by the manual so i will have to try that. I put the wheel on the balancing stand and gave it a good spin and I can see a pretty good wobble so I think something is up with the tire. I will run it by the dealer in the morning and get it checked out.

Is it beaded on the rim properly?

If not, let it down, put some super slippery soapy water round the bead and re inflate.

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Is it beaded on the rim properly?

If not, let it down, put some super slippery soapy water round the bead and re inflate.

My buddy had a Kenda 776 rear that had a broken bead, and it ran exactly like you describe. It was, however, very easy to see with the eye, the bead would just not seat on the rim fully.

Not saying that's what your situation is, and there could be a million other variables, running from the front tire to the forks being clapped out or adjusted all wrong (and consequently there not being any damping, leading to the pogo stick feel).

Good luck

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Well, I had a local shop true the rim, reseat the tire, and balance it and it's still there. I took the head apart to check the bearings and they seem OK. I tightened them up a tad but it didn't make a difference. I have not yet balanced the rear tire - could that have any effect on the feel of the front one?

I wish I knew someone local with a drz. I would like to throw a different wheel/tire on and see how it behaves. Barring that, I will probably buy a pirelli mt21 to put on and see what happens. If it's still there after that I guess I am looking at a fork/swingarm disassembly.

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The idea I'm getting in my mind is that the tire is misshapen after riding it when the wheel was out of balance.

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I hadn't thought of that. These were on the bike when I bought it and there were no weights. I don't know how long the PO rode on them but they appear relatively new. I will try to get some video of it spinning on the balancing stand.

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I tried to take a video with my iphone but the 'wobble' just didn't come across very well. I am fairly certain something is up with the tire. Here is a picture of it so you can see it's condition. You can also see my homemade weight to offset the rim lock. The shop used that in addition to some lead weights to balance it.

be65a00c.jpg

Doing the 'wire against the rim' process to check the runout, the rim looks pretty spot on (the shop checked this too). If I move the wire up by the lugs of the tire I get difference of probably 1/8" from the closest to nearest lug so it's like the tire is shifted but the bead itself around the rim doesn't show a variance like this.

Here are a couple pictures of the wire by the lugs:

Farthest:

e960414e.jpg

Nearest:

b9dda0e1.jpg

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you should ditch the rim lock and try it again. the rim lock is for off road using a knobby.

yep, ditch the rim loc.

something funky with the tire from your pics also, imo. maybe caused by the loc's, looks like about 3/16 difference or more? that can't be good.

Edited by topaz250
remove front rim loc only

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Possibly but pics a little vague. In the first pic the right fork tube bottom looks like it has a little rash possibly????? If you can lift the front end off the ground spin the wheel and turn the handlebars from lock to lock, if the wheel abruptly stops or slows down significantly it could mean the forks are either missalligned or bent. Could be where your variance is coming from. Could also be a bent rim but both are possibilities.

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It sounds like your bike may have sat on a flat tire fo a long time. i would put on a new tire . had the same problem with my e model . tire fixed it.

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Balance both wheels. I recomend running the rear rim lock...especially if you like to wheelie. I ripped my valve stem off at 55MPH on the highway after frequent wheelies and no rim lock. It was a scary ride. Glad it happend on a straight stretch and not on a curve.

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