I've tried to go on 3 longer rides so far on my "new" '83 KX500.
The first time the bike was alright but it kept trying to grenade itself. The rear fender fell off. I realised the front axle was the wrong one for the bike, and whoever put it in only swapped one bearing to the new ID. So the wheel was free to float around on the brake rotor side. I was able to ride the bike back home.
So I changed the bearings, went all through the carb and re-set all the jetting, cleaned the petcock filter, fixed my rear fender, cleaned my filters and all that fun stuff.
The second time I went out, I got about 20 minutes into the ride before the bolt holding the top of the rear shock in place snapped, but I was able to ride the bike back to an easily accessible area to load it in the truck and take it home. Upon closer inspection I noticed the shock is not original, and someone had jerry rigged a linkage to fit it into the rear end of the bike, and the one bolt that was holding the top of the shock was way too small and the way it was positioned made it very easy to snap the head off. The engine ran great though.
So I took the pivot out, cut off the crazy bracket and fabbed up a much better bracket (with correct geometry for once) to adapt to this mystery shock.
The third time I went out, the bike was better than ever, the "revised" suspension geometry meant that the rear shock was actually working properly instead of just sitting on the bump stop all the time, and I was able to ride the bike a lot harder for it. I got about 30 minutes into the woods before the entire rear shock suffered a rapid disassembly (aka the thing exploded), the damping rod is still MIA. Apparently that shock wasn't meant to work. When the shock came apart over a bigger bump, the rear end collapsed, sending the back tire into my subframe and tearing off the fender in the process. The rear wheel locked itself up and I came to a stop. Fortunately I wasn't going fast and I was on dirt (I had been going ~90mph on gravel earlier in the day). This time I had to drive my truck deep into the woods to load the bike up and get it home (Oh FYI - riding 30 minutes 2-up on a KTM - not so much fun). When I got the bike home I also noticed that I popped a front fork seal, which did a good job of covering the whole front end in fork oil...
But the engine runs great!
So now the bike is back up on my "hoist"... gotta love old machines. I've got a new Millville for the rear and a new Pirelli for the front, and now I just have to find myself a shock on eBay, and fab up another new linkage if need be. I might as well find a set of forks too, cause these old things are crappy anyways. Then I could mount a decent caliper, and a new brake master, and get a new hub... I think new handleabars would be good, too....
Any suggestions which parts I should be buying?