Ignition advance/retard
Posted: 24 Sep 2017 19:35
Hi Folks,
Been working on the other Morini, 1979 3 1/2 Sport, red pickup, blue transducers. Going great but...
Checked the timing, spot on, wait a minute, how come it's only about 6mm behind the ANT mark at tickover,?. Change the pickup for my spare red one, slightly better but the same really, about maybe 8mm retarded from the ANT (full advance)mark at tickover (1200 rpm or less), when revved goes to the ANT mark, place a diode in line at each transducer, lo and behold, retarding I guess to maybe 12 to 15 degrees advance at tickover, that's around 25 to 28mm from the ANT mark at tickover (toward the TDC mark). I wonder if the diodes in both the red pickups have gone?. My spare one is from my orange bike, which I had ignition advance problems too.
As I have a strobe from way back in the last century, without any advance feature, I wondered if what I have just described sounds like I've got it right?, I doubt it should be ticking over at aprox 28 degrees advanced? (guesstimate). It was starting first kick, hot or cold, not kicking back, but was slightly flat mid range, and when giving it A tutto gas, it would eventually start popping and banging until I laid off the throttle, then run fine, running too hot because it's not retarding enough after revving?.
I suppose riding it would tell a lot, but I just saw an Ark floating down the middle of road with some old geezer with a beard at the helm!
Any constructive comments gratefully received.
PS
Further to this, I said resistor instead of diode, senior moment. And when I max the screen on Sorens video it looks like at 1200 rpm it should be around 21 or 22 degrees advance. The riding of the bike should tell.
Thanks
Alan.
Been working on the other Morini, 1979 3 1/2 Sport, red pickup, blue transducers. Going great but...
Checked the timing, spot on, wait a minute, how come it's only about 6mm behind the ANT mark at tickover,?. Change the pickup for my spare red one, slightly better but the same really, about maybe 8mm retarded from the ANT (full advance)mark at tickover (1200 rpm or less), when revved goes to the ANT mark, place a diode in line at each transducer, lo and behold, retarding I guess to maybe 12 to 15 degrees advance at tickover, that's around 25 to 28mm from the ANT mark at tickover (toward the TDC mark). I wonder if the diodes in both the red pickups have gone?. My spare one is from my orange bike, which I had ignition advance problems too.
As I have a strobe from way back in the last century, without any advance feature, I wondered if what I have just described sounds like I've got it right?, I doubt it should be ticking over at aprox 28 degrees advanced? (guesstimate). It was starting first kick, hot or cold, not kicking back, but was slightly flat mid range, and when giving it A tutto gas, it would eventually start popping and banging until I laid off the throttle, then run fine, running too hot because it's not retarding enough after revving?.
I suppose riding it would tell a lot, but I just saw an Ark floating down the middle of road with some old geezer with a beard at the helm!
Any constructive comments gratefully received.
PS
Further to this, I said resistor instead of diode, senior moment. And when I max the screen on Sorens video it looks like at 1200 rpm it should be around 21 or 22 degrees advance. The riding of the bike should tell.
Thanks
Alan.