Just picked up an '05 DR-Z400S with 6k miles on it. First ride I notice a mild/moderate pulsating/oscillating shudder or vibration from the front end/front wheel that comes and goes every second or two, increasing with speed, not noticable at low speed/less than 30 MPH. Has well worn original deathwings on it. It's not dramatic but it is enough to shake the handlebars/instrument cluster a bit. I'm used to pure street bikes and pure dirt bikes (V-Strom and WR450) and haven't experienced anything like this on those bikes. Is this the way these bikes are at highway speeds or is this an out of round wheel, an inblanaced tire, or something else?

Edited by eyesurgeon, 16 June 2012 - 12:49 PM.

tire condition , tire pressure , a wheel balance should answer your questions .

if it was used as a stunt bike by the PO would not be of any benefit to you

Funny you should post this.  I had the same condition about a week ago.  Yours may turn out differently, but on mine It turned out to be a bad front wheel bearing.  I only just discovered the true cause today as I am tearing the front end down for a fork rebuild.

Before I took the front wheel off I instinctively pushed the wheel from side to side.  It had a lot of play. When I pulled the front wheel off bearing balls were hitting the shed floor.  Glad it didn't lock up on me while I was riding it.

Interesting, I hope that's not my problem.

This is the shelled bearing that I found.

man ... that's nasty

Another vote for wheel bearings. My DR350 had the same symptoms...new bearings and all better.

Had a similar issue since I owned my bike, just started using it to communte and needed this fixed, it was AWFUL at freeway speed. Need to make sure both front and rear wheels are balanced, I thought it was my front that was causing the problem, but balancing and having the wheel rebuilt did not help, rear needed to be balanced, took over 4oz of weight to balance against rear Rim-Lock even with bran spankin new rim, using  Dunlop 606 Tires.

Basic troubleshooting is needed here.

First thing that sticks out is "still on well worn original Deathwings."

On to troubleshooting: First off, get the bike into the air and spin a wheel.
-Is the wheel true? Are there any bent or broken spokes? Is the rim bent or out of round in any way? Any notchiness from the front wheel bearing?
-Is the tire balanced?
-Are the tires properly inflated?
-Are the tires in good condition? (as noted, they are not)
-Is there any notchiness in your steering stem bearings?
-Where are the settings at on your front suspension?

While the bike is in the air, how is your back wheel? Chain and sprockets? Is your rear wheel aligned?

Good luck, hope you sort it out!

Thanks for the suggestions guys. I've got some new tires on order and I'll report back.