When are you getting this wheel hop? My friend had wheel hop on his Harley and that was sitting at idle the damn front end would jump off the ground at idle, now I know this isn't happening on your KLX. Is it at 30-50 60 75mph?, sure helps in the diagnosis, also can you drive out of it say it hops at 40mph does it go away at say 55mph, usually a sign of out of balance.

 

The wheel hop gets worse with speed up to a point. At ~25 MPH it's a mild "rumble" and at ~50 it's getting about an inch and half of fork travel, faster is about the same.

 

Is it your rimlock? Just askin'!

 

The wheel hop gets worse with speed up to a point. At ~25 MPH it's a mild "rumble" and at ~50 it's getting about an inch and half of fork travel, faster is about the same

sounds the same as my rear wheel after I fitted the rim lock but before I had the wheel balanced

 

No rimlocks or slime in the wheel itself. It has a heavy duty tube inside the Dunlop 606. I don't remember the wheel hop when the tire was new but, it was really squirrelly until I figured out the air pressure it needed.

I run 20PSI front and rear. The rear is okay at 22PSI. Any more air pressure and it's like the tires are on ice or a road after the first rain when all the road oil is lifted out of the asphalt. Under 18PSI and it feels like I'm running on a flat with plenty of sidewall flex.

Keep the ideas coming! You have provided a lot of good advice and thoughts so far. This weekend I'm going to see about getting my ride on a stand using the coat hanger trick to see if the wheel is out of round.