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Absolutely. The recommended timing from SnS was about 3 degrees too far advanced. Next time on the dyno the motor ran more consistently..
BTW didn't know that people were running cow farts for fuel.. I suspect that you mean Methanol.
I've got a buddy that runs Land speed car. Shooting for the record for four wheels.. He runs methanol without any water-jackets on the block. The methanol cools the motor..
Yeah cow farts... Lol... Or should I say Brain Farts.... Thanks..
Been doing my shovels like that for decades. I use a degree wheel to accurately mark the rotor and the primary cover in 5 degree intervals and to make sure the flywheel marks are true. Have been off on occasion.
This is what I do. Take the inspection plate off the primary ( where you adjust the primary chain ), I've marked the rotor and a corresponding mark directly across from it on the primary chain adjuster. This was marked with white paint and corresponded to top dead center on the flywheel. Then using my timing light with the advance dial set to your bikes specs, check the timing and adjust the timing plate as necessary. This bike has the Dyna 2000i ignition.
This is a very accurate way to check the timing, but you still get a bit of oil splashed out when you are running the bike. As long as you don't have a need to remove the rotor off the stator, you can continue to use the marks.
This is what I do. Take the inspection plate off the primary ( where you adjust the primary chain ), I've marked the rotor and a corresponding mark directly across from it on the primary chain adjuster. This was marked with white paint and corresponded to top dead center on the flywheel. Then using my timing light with the advance dial set to your bikes specs, check the timing and adjust the timing plate as necessary. This bike has the Dyna 2000i ignition.
This is a very accurate way to check the timing, but you still get a bit of oil splashed out when you are running the bike. As long as you don't have a need to remove the rotor off the stator, you can continue to use the marks.
With a good digital ignition module, you really don't need to do dynamic timing with a strobe light.. The good thing about digital is that there isn't any mechanism to wear out..
On my 113 SnS motor, with a 2000i, it needed curve 4 with the static timing TDC set to the far left of the hole.. Set in the center, it didn't ping but successive runs on a dyno lost power as the motor got hotter and hotter.
Originally Posted by 98hotrodfatboy
It would lose power, as heat is the enemy... This is why with E85 and Methane you can give it more timing to make more power because it doesn't create as much heat.. Bigger motors can't take timing advance like a small block .
Sometimes when this happens I literally go up a intermediate jet and leave the timing, readjust the carb.. I find fuel is in some ways a cooling for the motor. There is a balance in tuning and sometimes that last hp or two can be had in more than one way. Comes down to is it running better with more advance slightly rich, or retarded slightly lean. Also I find fancy ignition systems that make a great spark don’t continue to hold or keep up when the engine is under a load. In other words, I found a way to keep timing not go too rich but increase my spark to compensate. Folks make fun of the dynaS but if you play with the weights.. I’ve never found the new hot ignitions to compete with the dynaS and a stock late model evo coil. I gap between 48 and 55 thou, indexed.
the give away is at near the end of the traps, or when really staying in gear on the street it starts to cut up a bit… it’s the ignition. You can close the spark plug gaps and the cutting out stops but then there is detonations. The Dyna S … no cut out. I’ve used the 2000i, hi4, Mallory and a few others. I’ve tried dual fire single plug, dual fire dual plug, single fire dual plug, single fire single plug.. at the end of the day, single plug with Dyna S and an over the counter late model evo coil have proved to be the ticket.
Last edited by Rains2much; Nov 22, 2022 at 06:14 AM.
Sometimes when this happens I literally go up a intermediate jet and leave the timing, readjust the carb.. I find fuel is in some ways a cooling for the motor. There is a balance in tuning and sometimes that last hp or two can be had in more than one way. Comes down to is it running better with more advance slightly rich, or retarded slightly lean. Also I find fancy ignition systems that make a great spark don’t continue to hold or keep up when the engine is under a load. In other words, I found a way to keep timing not go too rich but increase my spark to compensate. Folks make fun of the dynaS but if you play with the weights.. I’ve never found the new hot ignitions to compete with the dynaS and a stock late model evo coil. I gap between 48 and 55 thou, indexed.
the give away is at near the end of the traps, or when really staying in gear on the street it starts to cut up a bit… it’s the ignition. You can close the spark plug gaps and the cutting out stops but then there is detonations. The Dyna S … no cut out. I’ve used the 2000i, hi4, Mallory and a few others. I’ve tried dual fire single plug, dual fire dual plug, single fire dual plug, single fire single plug.. at the end of the day, single plug with Dyna S and an over the counter late model evo coil have proved to be the ticket.
This is interesting stuff. My read is a little different. Not saying I'm right but I have a different theory.
I suspect that what you found is that the spark with the Dyna S actually got weaker as the Rs went up.. It slowed the burning in the combustion chamber at higher Rs and staved off the detonation. The Dyna S is likely a simple solid state mechanism without a microprocessor to set the advance. An advance mechanism is needed. In this case the coil dwell is set by position of the rotor and is a percentage of the rotation. As RPMs go up, dwell time goes down, coil saturates less and spark weakens. Now the later ignitions likely have longer dwell times to keep the spark hot.. The fact that you closed the gap and saw detonation says too much timing.
So why were you faster with the Dyna S?
I'd say it's because of the retarded burn at RPMs. By the end of the track, chambers are hot, and they like the slower burn. What you could do is program in a retard in a newer programable ignition but I also suspect that programming in a retard as going down the track would help. I remember back in the 70s guys were typically using ignitions that would back off on the timing at shift points.
The newer EFI stuff on street bikes (delphi , speed density) actually predict timing and feuling based on head temp and engine load..
i run an open primary on my Shovel & to stop any oil mess when timing I had a degree wheel sticker made & installed it on the front pully, really made timing easy & fast, I also use glass pushrod covers so finding front compression stroke is also an oil free process as ya dont disturb the seals,
could this help if fitted to the Compensator Sprocket on your Evo ??
This is interesting stuff. My read is a little different. Not saying I'm right but I have a different theory.
I suspect that what you found is that the spark with the Dyna S actually got weaker as the Rs went up.. It slowed the burning in the combustion chamber at higher Rs and staved off the detonation. The Dyna S is likely a simple solid state mechanism without a microprocessor to set the advance. An advance mechanism is needed. In this case the coil dwell is set by position of the rotor and is a percentage of the rotation. As RPMs go up, dwell time goes down, coil saturates less and spark weakens. Now the later ignitions likely have longer dwell times to keep the spark hot.. The fact that you closed the gap and saw detonation says too much timing.
So why were you faster with the Dyna S?
I'd say it's because of the retarded burn at RPMs. By the end of the track, chambers are hot, and they like the slower burn. What you could do is program in a retard in a newer programable ignition but I also suspect that programming in a retard as going down the track would help. I remember back in the 70s guys were typically using ignitions that would back off on the timing at shift points.
The newer EFI stuff on street bikes (delphi , speed density) actually predict timing and feuling based on head temp and engine load..
I always felt that lower the timing at shifts actually created more torque which would aide in quicker times and when setting the timing curve with a PowerVision this is automatic.. As for head temps and timing, I agree on timing set back to Cool things down a little. However with todays tuners one can block the head temp/retard function if they desire but why??? The really neat thing about these tuners is that you can keep different tunes loaded in the tuner for changes in atmospheric conditions.. Love that function... I'm currently running my bike in open loop.. I don't have wide band..
Been doing my shovels like that for decades. I use a degree wheel to accurately mark the rotor and the primary cover in 5 degree intervals and to make sure the flywheel marks are true. Have been off on occasion.
They been selling a bolt in gadget forever too.
I had one of these 30 years ago on a shovelhead with an open belt primary. Worked great.
