Its been a while since I've posted, but I searched the forum and I couldn't find these topics posted previously. Anyway...
1. On my single seat buggy, I have a swingarm rear suspension and I love it. Does some things that the IRS can't do, but I digress. I have my engine mounted to the swingarm (see photo), which obviously adds some significant weight to the swingarm. I have noticed that most, if not all, swingarm buggy's have the engine mounted to the swingarm. I am weighing the pros/cons of mounting the engine to the buggy frame and allowing the swingarm to pivot below and free of the engine. I know this will add weight to the rear of the buggy and I will need a jackshaft in line with the swingarm pivot. Anyone have any other pros/cons? Why is the engine always mounted to the swingarm, simplicity?
2. On my 2 seat buggy, I have short front A-arms, approx. 10" long (see photo). I did this on purpose to maximize cockpit space and minimize overall width. I currently have approx. 5" of travel on the front end (mostly limited by the shocks). I have debated over modifying the front suspension to increase the length of the A-arms, (I am still researching shock replacements). Are there any advantages to longer A-arms other than travel?

A arms, longer increases comfort over rougher terain, as for the swing arm....how will you transfer the energy from a stationary jackshaft to a floating staight/live axle........would require a gear box and half shafts, would it not? Just my thoughts....
Tim

My plan for the swing arm is to mount the engine as high as possible under the rear 'rack'. I will have a total of 2 jackshafts: 1 for the driven clutch of the torque converter, and the other will be centered between the 2 swing arm pivot mounting points. This way, the center of the second jack shaft will be directly in line with the swing arm pivot points (similar to the engine sprocket location of some ATV's eliminating the need for a chain tensioner). The jackshafts will be connected via chain and then I will have a chain from the second jack shaft to my axle. This can also greatly increase my possibilities of gearing options (if I ever get so inclined to mess with that enough). It will be lots of additional work, but I think it will greatly increase the functionality of my suspension. Besides, when we build a buggy, are we ever really 'done'?

If you keep the output going to your axle plum with your hinge for your swing arm then you want have any problems with keeping your chain tight with a tensioner. A arm length you need to experiment with length of your buggy has a lot to do with it to short rough ride to long and the nose will dive in the corners. I used the a-arms lengths off a 4 wheeler with the same deminsions as my buggy.