Hello and Welcome jmms!
First, let me say I think it's cool that you are still riding
While raked cups are common and popular in the chopper and ccustom cruiser scene, I don't think they are easy to find for street bikes other than maybe drag racers.
The approach to change the rake in order to make steering easier requires careful planning. The trail is actually the dimension that is responsible for steering effort and the shorter the trail, the easier (and sometimes more quirky) is the steering. Usually, for any three-wheeler set-up it is desirable to have a
longer trail in order to increase straight line stability. Otherwise, you have to apply constant pressure on either side handlebar in order to make your rig go straight and you will get tired and sore rather quick. So, there is a trade-off and it is important to find the right compromise. I raced sidecars in the 70s and the front-end geometry was key to track performance and handling depending on how long a race was and how curvy the track.
The picture below should help you understand how rake and trail play with each other and how a rake change will affect the trail. Personally, if you have to have something made, I would propose to change the "offset" in the triple tree by having a custom triple tree set made, which anyone with a decent machining set-up working in billet aluminum can do. As you see in the drawing, an increased offset will move the forks forward, thus decreasing the trail. This will be more efficient than using "raked cups", which in most cases only change the lower or upper cup to "off-center" and will achieve only a limited change.
See what you think. I am interested in talking about this a little more.
