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geo46er said:
You read the part about how points performance can vary greatly? Even the worse EI is going to be at least consistant. :mrgreen:
Commando Timing Advance Curves Compiled
- Thread starter rick in seattle
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You read the part about how points performance can vary greatly? Even the worse EI is going to be at least consistant. :mrgreen:
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- Jan 1, 2009
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I've got to go with Dave on this one. At 2000 rpm, the AAU, depending on unit, could produce 8 degrees advance or 20 degrees. No modern bikes use mechanical advance units. Regardless of which vendor you pick (ok, let's exclude the analog Boyer), you're better off with an EI. The EI may have its warts, but they're the same warts every time, every unit.
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- May 7, 2005
- Messages
- 7,166
Been having problems with pinking on my Victor, only between 2K and 3K. Got it reduced by moving needle upwards and uping main jet but could not totally get rid of it except by retarding the Boyer Analogue from 28 to 25. Did an experiment yesterday by swaping the box for a Boyer microdigital, kept the stator and rotor same as they are the same parts.
1. Just changing the box retarded the fully advanced timing enough to have to reset the rotor on the cam.
2. When retimed to 28 fully advanced the pinking has completely dissappeared. So the curve must be starting at a more retarded point and advancing steeper.
3. When reducing the tickover using the throttle stop you get this zone where it makes no difference. This must be the idle stabilisation kicking in.
4. As Debby noted, throttle stabilisation or not the tickover varies, it didn't with the boyer analogue.
As the Victor is twin plugged next experiment is to go for 30/31 fully advanced.
1. Just changing the box retarded the fully advanced timing enough to have to reset the rotor on the cam.
2. When retimed to 28 fully advanced the pinking has completely dissappeared. So the curve must be starting at a more retarded point and advancing steeper.
3. When reducing the tickover using the throttle stop you get this zone where it makes no difference. This must be the idle stabilisation kicking in.
4. As Debby noted, throttle stabilisation or not the tickover varies, it didn't with the boyer analogue.
As the Victor is twin plugged next experiment is to go for 30/31 fully advanced.
A couple of comments, for what they're worth, relative to RickinSeattle's chart of curves;
After looking at Dave Comeau's Boyer analog chart it appears that the curve shown by Rick was the worst case of the 4 different curves shown. The curves shown by Dave are not variations of a single unit but measurements taken on 4 different units. The indication by Dave was that apparently the 4 units were within Boyer's specs, so depending on the luck of the draw you could have a unit that gave +/- 8 deg advance at 1000 rpm or +/- 14 deg advance at 1000 rpm. This probably explains why some people have had good success with a Boyer and others not so good. Still the big issue with the Boyer regardless of advance curve is the susceptibility of erratic timing at low voltages. Well to be fair it is analog and a fairly old design but it did offer a big step forward from the mechanical points and advance that was a pain to set and maintain. BTW the Pazon curve was higher than the lowest Boyer curve at 1000 rpm and the Trispark was about the same as the lowest Boyer curve at 1000 rpm, interesting.
That said, I put my money into a Trispark, since my MK III will eventually get a working starter, but only time will tell if it can hold up to the Tropical heat of South Florida. If I had a non-E start Commando I wouldn't be too worried about using a Boyer and taking the money I saved over the Trispark to buy a battery tender and an AGM battery. Oh yeah I would check the Boyer's timing at idle to see if I got lucky and got a good one or not.
Scooter
(God willing eventually I'll get the beast running again)
After looking at Dave Comeau's Boyer analog chart it appears that the curve shown by Rick was the worst case of the 4 different curves shown. The curves shown by Dave are not variations of a single unit but measurements taken on 4 different units. The indication by Dave was that apparently the 4 units were within Boyer's specs, so depending on the luck of the draw you could have a unit that gave +/- 8 deg advance at 1000 rpm or +/- 14 deg advance at 1000 rpm. This probably explains why some people have had good success with a Boyer and others not so good. Still the big issue with the Boyer regardless of advance curve is the susceptibility of erratic timing at low voltages. Well to be fair it is analog and a fairly old design but it did offer a big step forward from the mechanical points and advance that was a pain to set and maintain. BTW the Pazon curve was higher than the lowest Boyer curve at 1000 rpm and the Trispark was about the same as the lowest Boyer curve at 1000 rpm, interesting.
That said, I put my money into a Trispark, since my MK III will eventually get a working starter, but only time will tell if it can hold up to the Tropical heat of South Florida. If I had a non-E start Commando I wouldn't be too worried about using a Boyer and taking the money I saved over the Trispark to buy a battery tender and an AGM battery. Oh yeah I would check the Boyer's timing at idle to see if I got lucky and got a good one or not.
Scooter
(God willing eventually I'll get the beast running again)
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- Oct 29, 2006
- Messages
- 1,075
"Well to be fair it is analog and a fairly old design but it did offer a big step forward from the mechanical points and advance that was a pain to set and maintain. "
What the analog boyer did was provide a system that didn't require periodic adjustment BUT, at the same time (IMO) it's bad characteristics (not enough advance at midrange, too much advance at kickstart speed, needs too much power) outweighed the good one. I pulled the Boyer shortly after buying my Commando and went to the oem points/AAU for better performance in every way. OK, yeah, you have to check/adjust them periodically. I had no intention of ever bothering with an E ignition. But the Trispark's data/reports convinced me that it was a realistic replacement for the oem ignition. I bought one and I think it's great.
I have to admit that I still find myself concerned about the unit being in the timing case as far as heat/vibration but I have not heard of any issues and I did a lot of research on that before buying it. It get's pretty hot Down Under from what I understand...
What the analog boyer did was provide a system that didn't require periodic adjustment BUT, at the same time (IMO) it's bad characteristics (not enough advance at midrange, too much advance at kickstart speed, needs too much power) outweighed the good one. I pulled the Boyer shortly after buying my Commando and went to the oem points/AAU for better performance in every way. OK, yeah, you have to check/adjust them periodically. I had no intention of ever bothering with an E ignition. But the Trispark's data/reports convinced me that it was a realistic replacement for the oem ignition. I bought one and I think it's great.
I have to admit that I still find myself concerned about the unit being in the timing case as far as heat/vibration but I have not heard of any issues and I did a lot of research on that before buying it. It get's pretty hot Down Under from what I understand...
- Joined
- Oct 19, 2005
- Messages
- 18,978
There is a comprise solution that really appeals to me now for
anything but maxed out rpm and power attempts,
old points system with transistor gizmo interface that takes
the current off the points. Too bad mech. adv. unit are not
being made anymore, but good ones still exist if you keep
hunting and talking novices out of them.
To me nothing beats a basic factory Norton, dual Amals on points
for basic daily use and zings into many sane thrills off 1st time
every time kick starts no matter time set up on low or no battery.
My 1st bike was wining P!! dragster barely made legal, too
low to turn by leans but instant off idle response to spin
tire to aim any way ya liked then left off throttle till
tire hooked up and leap on out of there. 1st kick starts
if not broken foot on 11+:1 CR, idled 600 rpm and
easy street or deep sand creeping on the torque and light flywheel.
Would not stall down off idle hi throttle twists, wonderful.
Almost anything replaced with modern gizmos takes
some the response and light operation off pure Norton good ness.
My hope to exceed the stock ignition response and
steady idle and avoid the compromises listed here,
To program it - displays the curve on 'puter screen
and ya just grab the graph line and drag it to any
degree at any rpm your bike likes, plus rev limiter.
3 sparks per stroke to make sure its all lights off.
For cold starts can make 1st spark early so 2nd one
has some vapors to burn and then soon after 3rd spark to
get er going. Much more interesting involvement for
the too easy bored among us.
http://www.powerarc.com/
hobot
anything but maxed out rpm and power attempts,
old points system with transistor gizmo interface that takes
the current off the points. Too bad mech. adv. unit are not
being made anymore, but good ones still exist if you keep
hunting and talking novices out of them.
To me nothing beats a basic factory Norton, dual Amals on points
for basic daily use and zings into many sane thrills off 1st time
every time kick starts no matter time set up on low or no battery.
My 1st bike was wining P!! dragster barely made legal, too
low to turn by leans but instant off idle response to spin
tire to aim any way ya liked then left off throttle till
tire hooked up and leap on out of there. 1st kick starts
if not broken foot on 11+:1 CR, idled 600 rpm and
easy street or deep sand creeping on the torque and light flywheel.
Would not stall down off idle hi throttle twists, wonderful.
Almost anything replaced with modern gizmos takes
some the response and light operation off pure Norton good ness.
My hope to exceed the stock ignition response and
steady idle and avoid the compromises listed here,
To program it - displays the curve on 'puter screen
and ya just grab the graph line and drag it to any
degree at any rpm your bike likes, plus rev limiter.
3 sparks per stroke to make sure its all lights off.
For cold starts can make 1st spark early so 2nd one
has some vapors to burn and then soon after 3rd spark to
get er going. Much more interesting involvement for
the too easy bored among us.
http://www.powerarc.com/
hobot
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