What did you do to get the spark back? I have pretty much the same problem with my XBR which has stood for 18 months and I'm struggling. The resistance readings I'm getting are different to the manual ( may be my multimeter) and I don't seem to have any voltage going into the HT coil. I'm slowly working my way through so any hints would be much appreciated!!
The answer is simple. We think we always had one! We just weren't kicking hard enough! Plus the spark is "thin" so not easy to see, especially against the aluminium head and the fact that each kick moves the bike a lot.
Basically we started undoing every bit of sheathing on the original loom and started to build our own very much simplified loom. When we got enough wires in place to theoretically provide an ignition switch, fuses and an ignition circuit we tried for a spark. Because we thought we weren't getting one we tested for voltage at the coil and found virtually nothing so assumed that by leaving out all the circuit for the starter motor and all the various "safety" devices, that we'd inadvertently shorted the coil or something.
My bro has another xbr in standard ish trim, with a starter motor, so we tested that for a spark using the starter motor. We got a spark albeit a slightly "thin" looking one. We then tried the kick start and at first the spark seemed to have gone AWOL. But as we'd had a spark by the starter motor only minutes earlier we looked more closely. And realised there was a weakish looking one after all.
We then disconnected all the connectors associated with the bits we don't want on his (my bro's) cafe racer bike to prove that the ignition will still operate. It did. So we realised that all along we'd probably just not been looking hard enough. At this stage the lack of "static" voltage at the coil was still a mystery.
We took our home brewed, half finished loom off the project bike and transferred the loom from the standard bike. We soon were able to produce a spark.
We then tried to actually start the project bike, but to no avail. We gave up after an hour or so of trying, both kicking and bumping. The best we got got was a couple of backfires in the exhaust.
Now that I have a bit more info on how the spark is produced, we can explore further. The carb is a new mikuni slide jobbie so I need to check that is set up right. Then we'll have to check the timing as the engine was sent to a professional builder, who specialises in motocross. We need to satisfy ourselves that the timing is ok and not somehow completely out of sync. We have a spark, but we don't know if it is produced at the right time!
If we can provide anymore info Steve, just ask and I'll try my best! Likewise if you have a eureka moment, please let us know!
Best of luck.