Motorcycle Repair: Vintage Honda Ct90, honda ct90, rotor stator

Question
About a year ago a buddy and I(both college students) purchased a 1971 honda ct90. The bike worked for about 2 months and then over the course of 3 days started to dog down and then finally died. We had the fuel line replaced, carb cleaned, replaced all of the gaskets(including head)as the bike was not getting compression, replaced one valve and had the other cleaned, replaced the piston rings and had the cylinder honed out, replaced the spark plug, charged the battery, timing seems to be on. We had the compression tested and they said it was fine. The bike feels like it could turn over, but hasn't done so even with a shot of ether. What could be a plausible cause? I have read a lot of other posted questions to get insight...a lot of them talk about stator, coil and switches as being a problem.
Thanks  

Answer
Austin, Get an actual figure on the compression first. Factory readings indicate 170 psi. If you are down 30-40 psi then probably the cam timing is incorrect. If the cam is off a tooth, the ignition timing will be difficult to correct, as well. Point gap should be .014" and they should open on the F mark alignment on the rotor/stator. The point plate should be positioned so that the screws are in the middle of the adjustment slot on the backing plate, when the gap is set correctly and the timing is correct. Note: It is possible to put the point cam on the advancer 180 degrees out. Also, be sure that the advancer is locating on the pin on the end of the camshaft.

It is a battery operated ignition, so battery must be fully charged. Watch the ignition points as you crank the engine over. If they are arcing heavily on each open/close cycle, then the condenser is bad or disconnected from the point circuit.

Assuming that you have all the ingredients: compression, spark (at the right time), air/fuel mixtures it should fire up with a fresh plug that has a nice hot spark coming across the gap.

Honda coils seldom fail, but condensers do. Spark plug caps can get high resistances internally. Look for 5k ohms or so across the cap connections.

If you have been cranking and cranking the engine, trying to start it, you may have fuel fouled the spark plug. Put a new one in the plug cap, lay the plug against the engine to ground the outer shell and kick it over, looking for a nice yellow spark.

Hope that helps you some...
Bill Silver