I picked up a rear shock from a Raptor 125 ATV for $30 shipped. It’ll barely fit in the space available, but the Raptor 125 weighs about 300 lbs, (which is right around where I expect this bike to end up) and from what I read online, can handle a 200+ lb. adult rider quite well. It has about 2″ of travel, which should also work nicely. Of course, all this might be totally wrong once I get it together, but anything short of a $500 custom-calibrated Ohlins monoshock is a total crapshoot. At the very least, this one’s basically brand new and not total crap to start with. Given my bargain-basement strategy for this bike, it’s probably the best I can expect to find.
“…then Goldilocks said, ‘this one’s juuust right!'”
The Raptor 125 shock flanked by the XR100 and ZX-7 shocks purchased previously. The Raptor shock is actually longer eye-to-eye than the ZX-7’s, but the diameter is smaller and it doesn’t have that huge reservoir sticking out from it…not to mention spring and damping rates more in the ballpark for a lightweight roadster. (The spring retainer has already been removed from the Raptor shock.)
My no-buck spring compressor. Since the shock eye was actually bolted through the jack arm and I was using two separate Ancra tie-down straps, I figured it was a reasonably safe way to do it.
The shock position mocked up w/ front patterns of HDPE and rear arms made from aluminum channel. Of course, neither of the two shock linkages from production bikes that I’ve purchased to use there will work — one’s too short and one is too long. I have to work out just the right length; there’s a very narrow window between the shock hitting the swingarm and hitting the frame at some point within the range of suspension travel. I haven’t had a chance to play with the dogbone links from the rear eye to the swingarm, but I’m considering some sort of turnbuckle linkages so I can adjust ride height after it’s all together.
The dogbones (or turnbuckles) will have to attach outboard of the swingarm mounts, since the Raptor spring is just narrow enough to fit between the two sides of the swingarm.