So why not recommend running the bike with the condensers installed but disconnected then Mark? if your little box failed just reconnect the existing blue/yellow wires and the condensers and good to go again. Seems a waste to risk the condensers for no real reason.
Up to a point, I do: the mechanical realities of the spark advancer, though, need some help to work with the extremely-fast transistors. The silicon can switch millions of times faster than the points can from ON to OFF (or vice-versa) and the points cams have looseness between them and their pivot post in these 50-year-old machines. This can, in the worst cases, make for multiple-opening events of the point on the cam's opening ramp when the cam, swung to its outer loose measurement by centrifugal force, bounces back against the post as the foot of the points pushes against it while opening them. This is REAL bad in the CB350/450 bikes, to where one must go in and shim re-create the now-missing plastic shims under those points cams (they were plastic in the 1970s, now long gone), such that the bikes will be hard to start when my box is added: shimming them back to the spec'd 0.002"-0.006" clearance between the end of the points cam and its retaining washer on the end of the engine's cam will fix it instantly. In the SOHC4 bikes I occasionally see a spark advancer so worn that it happens, resulting in a noticeable power surge at about 2500 RPM when the points cam finally quits bouncing around, as the Transistor Ignition will faithfully follow that erratic spark.
The condensors will change the opening event of the points to a ramp instead of a [chattering] step in current, and then the transistors switch at 0.60 volt. If the condensors are leaking then the current is up-down-up-down very erratically, the Transistor Ignition faithfully follows those moves (making it a Multi-Spark like MSD?) which makes the engine run very rough as the spark timing changes for each cylinder when the condensors make the sawtooth-like waveforms from leakage.
It's interesting to watch on an oscilloscope, but a major annoyance to try to ride with.
So: if the condensors are good, leave them connected to help the worn mechanical parts out and smooth the engine.
If the condensors are bad, just disconnect them (like mine) and enjoy the snappy low-end RPM below full spark-advance: it will feel more 'crisp', but if your advancer is badly worn it may feel 'stumbly' below full-advance when hot, instead.
