I've used a hitch hauler quite a bit in the past mounted on a 1/2-ton Dodge Ram pickup to carry 650 dual-sport bikes. Even with that fairly substantial vehicle, I had to add leaf springs on the rear suspension to keep it from sagging too much and to level my headlights. I used that thing a lot, but I never did like it.
I can't imagine using one on a Subaru Forester. Even if you were able to reinforce your hitch/frame mounting and stabilize it with some other materials, you would still have to beef up your suspension with airbags or something of the sort, if that's even possible on such a vehicle. If it is, it would cost a lot to do. If you don't, with all that weight hanging off your back bumper, your headlights will point at the sky and it would probably be detrimental to the handling of the vehicle.
If the weight of the KLR was carried over, or close to, the rear axle, that would be one thing, but when it's hanging off a carrier four or five feet or possibly more behind the rear axle, that's a lot of weight and leverage. A 400-pound KLR effectively turns into a 1,000-pound-+ KLR with that much arm. Now, throw in some bumps and rough roads, having to perform an emergency maneuver with the Forester: see what I'm getting at?
My two cents' worth is that it's a bad idea and not even possible and I wouldn't do it. If you don't have a hitch on your vehicle yet, I would either get whatever you need to work with the Curt tow bar. If you want a 2" receiver, I don't know if you can find a 2" to 1.25" adapter or not. I've never used a tow bar, but if you don't want to get a trailer, it would seem to me that would be your only option.
Have you considered just renting a small, open U-Haul trailer for a one-time use instead of buying one? Just a thought.
Last edited by planalp; 11-17-2011 at 01:12 PM.