I have a pristine condition 1982 yamaha xt200 with few miles that has been pickled and warehoused for nearly 20 years. 3 years ago it was uncrated, cleaned up and ran perfectly. I was parked for abotu a year. Since then it has run erratically or not at all. If it starts, it will run. But then cut out or just simply fail to start. Fuel supply is checked good, carb checked good, valves, compression all OK. The spark as tested on several new, clean plugs is weak or almost undetectable. I have chcked all switches and wiring. I suspect a failure inthe ignitions system, either the pulse coil or CDI unit. What are the test steps for verifying these components? Is there an aftermarket bolt on replacement ignition or sources of used parts? Factory parts if I have to just replace everything make this incredibly clean, low mileage bike uneconomically repairable. Note, teh selection box did not include the XT200 as a choice