The first way involves reworking the swingarm to function with the existing linkages of the RG 500. I wasn't particularly fond of this idea because of the money that I had just spent importing a swingarm so I examined Jerry Kirshnir's bike (as seen on this site) and decide to modify the frame to suit the swingarm. *** note you must modify your exhaust system to work with the new additions to the frame *** note #2 if you are terribly concerned about your pristine stock Gamma as a long term collectors item you should not do this modification!!
The easiest way to make the necessary modifications is with a bare frame so that there is plenty of room for you welder to work around (it also makes flipping the bike up-side-down a lot easier!!). The first item of business is to determine what needs to be welded to the frame so that you can attach the shock and bell crank linkages.
A piece of square stock (T6061 or 7071) should be welded between the upper frame rails just before they meet the swingarm pivot castings. This location will allow for a complete bead to be applied around the stock for optimum strength. (the round cross tube should be removed to allow for pipe routing and any lateral strength loss will be offset by the new cross member).
A piece of flat stock must also be welded to the cross-member that sits at the base of the swingarm casting. This will act as a good mounting position for the shock linkage bell crank mount.
Now is a really good time to become friends with a very nice machinist because your going to need him a fair bit. The first item that needs to be fabricated is the bell crank mount. This consists of a forked mount, similar to an RGV top shock mount but without the holes.
Some people "hog out" the existing swingarm pivot holes but, unless you have a proper jig and locking mechanism to isolate the frame, it is incredibly difficult to maintain accuracy. I personally prefer to use swingarm bushings (2) that have an 8 mm thick face to take up the slack of the narrower swingarm.
As the swingarm floats around loosely you will now need to fabricate two new swingarm connecting rods (an inappropriate term seeing as how they are made of flat stock) to link the swingarm to the bell crank. Depending on the amount of ride height and shock length that you want the increased length should be 10 to 15 mm longer that an existing RGV pieces. See accompanying illustration
The link arms need to be made in conjunction with the length of shock in mind. Here is a picture of a stock Suzuki late model shock that I have used as a place holder. It will eventually be replaced with a Fox or Ohlins unit with the appropriate sping rate.
You may recall from the introduction, I had mentiond that the exhaust routing would need to be modified due to the placement of the new cross member. With the stock exhausts, the top shock mount is located directly in the path of the exhaust routing, but this really wasn't a concern seein as how I was having a set of chambers custom made. The pipes are made from Pete Gibson specs for his "road" tuned pipe dimensions and were made by a local pipe builder named Jaws Performance. He is doing some new research with a double resonance pipe on his ski-doos and finding exceptional mid-range gains but for the time being I'll be sticking with the taraditional style of pipe.
Here's the finished installed swingarm on my bike. The pipes in this pic haven't been finished as of yet and chain alignment still has to be dealt with, but that shouldn't be to much of a problem. This system has not been raod tested yet so I haven't worked out all of the bugs, but this will give you a basic idea of how to install a super trick looking swingarm on your own RG
Cheers Revvin Kevin Kernohan
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