Yachtwin 1964 fires only one cylinder

[luskateer]

Hi,
i have an older 4 h.p. yachtwin......So far i have cleaned up carb, replaced coil pack and points and condensors, and plug wires and plugs. It only fires on one cylinder. I pull the lower plug and no difference. pull the top one and it dies.
what's left. reed valves. faulty flywheel, timing.....
Any help
thanks

 

[Daviet]

Re: Yachtwin 1964 fires only one cylinder

What is the compression like?
Have you checked the spark with a spark checker, what's it like, bright blue?