Doing a single shock mod works great if you understand the geometry and overall suspension characteristics that you are looking for. I've seen may guys with single shocks that look great but were not very well thought out.
There are several things to take in to consideration when doing this mod.
(1) What type of riding are you doing
(2) Leverage ratio
(2) Overall travel
(3) Shock length
(4 ) Shock spring rate
(5) Shaft travel of the shock
(6) Mounting points
(7) Suspension geometry
(8) Rider weight
The major manufacturers have spent years and a tons of R&D to get to a point where everything works together.
If you use a donor shock and swing arm try and keep the leverage ratios the same for optimal performance.
Finding a swing arm that would fit for me took some research and asking people on E-bay to give me specific measurements. For example I found a XT550 swing arm had the same pivot bolt diameter and the width at the pivot was close, but the center line of the swing arm was sightly offset so I had to compensate for that. An XT550 shock was to long and outdated so I used a Buell XB12 Shock. I had to move the mounting point on the swing arm to get the correct leverage ratio so it would function as it was intended to.
It can be a little complicated ,but can work really well if you understand some basics.
What wheel are you using? Do you know what swing arm length you want? How do you want your shock mounted? (vertical.. horizontal.. angled..?) I'll be glad to help if I can , Let me know.
