Spark Unit

[george]

I have problems over the past few years getting my 1981 CB750 FA, which I purchased new, to run consistently. It has a habit of running OK then cutting out and then difficult to start. I have had the carbs serviced proffessionaly and used petseal in the petrol tank. Problems still persisted this year after winter storage and having removed the spark units (ignition amplifier) I noticed that the resin on the face of the units have melted. I have seen on other forums that people have filled them with silicon, but if they have melted, what is the cause? Does it indicate that the rectifier is faulty and needs replaced. If the resin has melted from the spark units are they now useless and need replacing. The units are £75 each (around $90) so I do not want to spend money on them if they can be rescued. Can anyone help?

[LukeM]

With the unit being sealed and all, it makes it hard to diagnose and repair.  There isn't much in that circuit: pickup sensor, ignition unit, coil, wires, plugs.  The cheapest bet would be to find someone with a similar ignition unit, swap it out for a while, and see how it runs.  Then you can go about finding a replacement if the ignition unit IS the problem. EBay, MC junkyards, classifieds.

Not much help, I know.

Luke M