My Son got his learners licence for the bike recently and I've been out riding around with him a bit and noticed he his bike tended to wobble disconcertingly once in a while, I chalked it up to him being a new rider, but today I took his bike for a good ride and notice the front end seemed to want to wobble on me to if I gave the handle bar a little nudge at high speed. He has a 2006 KLXs, and I have 2009 KLXs, both have the same tires, but his are are a little more worn then mine.
My bike has a much more stable feel than his, it doesn't have that wobble when you nudge the handlebar at high speed.
Both tires are Dunlop D603F.
Do you think it's the tires or could it be something else?

Here are a few pics
His is the green.

2006 front tire

My tire 2009

 

I had this tendency to wooble two years ago, the fix in my case was to loosen the triple clamp, shake the front end side to side, then tighten it. My guess is that the wheel was not straight (not inline with rear) after a few falloffs.

 

I'd check for play in the wheel bearings & steering head bearings in the older bike.

 

Let a little air out of the front tire, if you have it topped off the bike rides on the center ***** too much.

 

I think most DS bikes wobble a little bit, and the amount of wobble is often eased or aggravated by tire tread patterns, suspension settings, spring rates, where you sit on the bike, aftermarket handlebars, headlight fairing/front fender design, higher center of gravity, inherently designed dirt bike geometry, and on and on and on. The deal between the OP's bikes may just be the slightly taller suspension between the two models of KLX...10" vs. 11". Unless something is actually wrong with the given DS bike, I don't them to be dangerous in this aspect...just a little disconcerting to newer riders or at least riders used to riding a more normal, rock solid feeling motorcycle...like a road bike.

 

Hmmmm a few years ago I have a weave....no not the hair kind, the front wanted to go back and forth. Ended up being a bad steering bearing that was dry and my nut was lose.....that just sounds wrong, Anyway I don't think that's what you got going on there. Hey side note, are you sure the green bike isn't a 2007?

 

Usually it's nut behind the wheel (handlebar) that is the problem!

 

Good eye, you are right. Little brain fart there.

I was wondering if maybe the slightly different suspension and taller profile might have something to do with it.

Anyway, thanks for the replies, I'll be looking at all these things a little closer today. I might try swapping the front tires on the bikes to see if that changes anything.
The wobble isn't real bad, and I probably wouldn't have thought anything about it if I didn't have the other bike right there to compare it too.
Still, I'd rather have my novice son riding the more stable bike on the highway if that's the way it has to be.

 

is the wobble at higher speeds?...i had speed wobble problems when the suspension was set too soft for my weight...

 

Would the front wheel being unbalanced cause the bike to wobble?