That seems to be the way with this project. Seamus came over to do his magic with the chain tensioner, and we got the cam timing figured out. (I hadn't accounted for chain stretch when I was lining up the timing marks.) He also helped with a few other pieces of the puzzle that I was scratching my head about, so I finally got the engine buttoned up and exhaust mounted. I installed a fresh spark plug, topped off the oil, and gave it a few kicks. Nothing. I sprayed some ether and tried it again, nothing. I checked for spark at the plug and it was weak. My KTM was in the garage too, and it needed my attention because we had a Thursday Night Trail ride coming up, so I pushed the XR250 back in the garage and gave it a rest.
My next shot at the XR250 yielded no spark at all. I convinced Seamus to stop by and help me out again, since he's much better with a multi-meter than I am, and together we tested the coil and CDI. Nothing wrong with either, but he did find that the kill switch was hooked up incorrectly. Spark was found. A push start later, combustion ensued. In fact it ran really well with a decent amount of torque off idle and smooth power, though I didn't push it too high in rpm. Clutch and tranny felt good too.
The next day I adjusted the idle air screw a bit and kick started the bike and ran it up to temperature. It runs quite well, but still has a hard time at idle so I might have to change the pilot jet.
But before I can get into that I have to replace the clutch cover gasket. It was leaking at a pretty steady drip, more than I could ignore, so now it's back into that job. When I replaced the cover the first time I'd missed a thrust washer hiding in the old cover, so I had to take it apart again and I don't think the sealant bonded very well the second time.
I've got a new seat cover coming, and new fork seals and bushings as well as new steering head bearings. We'll see how it goes after that, but I'm cautiously optimistic that this will have been worth it.