Earlier this year I bought a '78 Strada to satisfy a long term itch. It had had a high number of owners and had been a 'project' prior to my purchasing it. It ran, albeit not too happily, but with the arrogance of a number of rebuilds behind me, I knew I could sort it...
It had been fitted with a Sachse ignition, replacement coils and Denso Iridium plugs by the previous owner. My first job was to get it warm, set up the carbs and see what improvement I could easily get. The answer was nothing; ie it failed to run after the first few minutes and just as the carbs were close to being set up. All I could achieve was viscious kick back or sullen silence.
Over the next weeks (months!) I checked everything and I do mean everything, three times at least, ultrasonically cleaned the carbs and checked all jets and passages (Strada standard carbs and jetting throughout), checked compressions, varied the static ignition timing, checked TDC, plotted advance curves, checked all the wiring, coil resistance checks, HT system resistances, plugs by (multiple) substitution, even used a degree disk to measure the camshaft timing. All the Sachse end to end checks were perfect (plugs firing at correct point). All I had found was that the coil wiring was reversed (which I corrected early on) and that I had an L5 camshaft... The plugs sparked in free air but I didn't get a pulse on my inductive strobe, but then, would it flash when just kicking over?
The coils were of a non-specific make but checked out perfectly electrically, however my suspicion lay with them as the strobe check was the only failure.
I splashed out and bought two PVL coils and genuine NGK BP7ES plugs (having read about fakes being common), fitted it all and... it ran! A few moments of carb fettling and selection of curve 5 on the Sachse system and it ran very nicely!
Conclusions: Either the coils were faulty from new or damaged by being incorrectly wired when originally fitted. Lesson learned: Don't trust anything electrical (I am a mech eng!) even when it gives good results on the meter.
In retrospect, the spark generated by the PVL coils was far stronger than that from the originals and the new plugs had a lower and identical resistance, suggesting that ageing plugs do begin to fail.
My sincere thanks must go to mbmm on here for his patient assistance and helpful suggestions and to Morini Tom for confirming that my measurements proved I had a non standard L5 cam.
The bike runs fine, though I now need to fiddle with the bottom end jetting to make it perfect... and maybe that 'S' on the cases means I really do have a modified Sport engine fitted! Does anyone know the history of EYA 101T?