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[mtc]

or is this some kind of mysterious secret?

old days with mechanical advances, change springs, faster sooner

now what?

[Pat Conlon]

The timing curve in the FJ ignitions are hard coded and are shown in the Genuine Factory Service Manual.
Here’s an example



If you want a custom programmable timing curve the new Dyna ignitions will do that via your laptop.
The old Dyna ignition boxes had a selector switch for choosing timing curves.

[mtc]

The timing curve in the FJ ignitions are hard coded in and are shown in the Genuine Factory Service Manual.
Here’s an example



If you want a custom programmable timing curve the new Dyna ignitions will do that via your laptop.
The old Dyna ignition boxes had a selector switch for choosing timing curves.

looks like this is applicable for my 85

why the 2 lines with differing pressures? sea level vs? other elevation?

have an old  dyna now with a selector, i choosing curve #1( appropriate) 20 degree span max out at 2500rpm ( stock 4 valve motor) if there is an increase in compression, it comes later


the dyna have more advance at idle at 15 degrees vs stock a 5 for a total of 35, programmable to 40, keeping the 20 degree span, making the initial 20 degrees

the second line goes to 50 degrees? that is a lot at 6500 rpm am i reading it wrong?



and get 38 close to 4000rpm

the vacuum is irrelevant correct, it only activates when shutting off to clean plugs?

if i choose selector #2 ( so stock is in between #1 and #2) reaches max at 4500 rpm, so i could switch to #2 and do a seat of pants comparison

[Pat Conlon]

I saw this question coming...the two advance curves.
The lower curve (at low vacuum) is the normal advance curve.
The upper curve (at high vacuum) is the advance curve when the throttle plates are closed. This advance flash burns off any unburned hydrocarbons in your cylinders upon deceleration.
This is an emissions feature....not a performance feature.
This is why your plugs are white.

Read all about it: http://www.fjowners.com/index.php?topic=11690.0

On my bike I use the stock 84/85 TCI with a 5* advance rotor so all my advance values are increased 5* from the lower curve on the graph. I have disconnected the TCI vacuum advance function.
Makes reading my plugs more accurate.

[mtc]

I saw this question coming...the two advance curves.
The lower curve (at low vacuum) is the normal advance curve.
The upper curve (at high vacuum) is the advance curve when the throttle plates are closed. This advance flash burns off any unburned hydrocarbons in your cylinders upon deceleration.
This is an emissions feature....not a performance feature.
This is why your plugs are white.

Read all about it: http://www.fjowners.com/index.php?topic=11690.0

On my bike I use the stock 84/85 TCI with a 5* advance rotor so all my advance values are increased 5* from the lower curve on the graph. I have disconnected the TCI vacuum advance function.
Makes reading my plugs more accurate.

39 at 3500
idle at 10
you got a big motor, high compression, maybe a few degrees here or there is overrated

thanks for the link and info Pat

[FJ1200W]

The timing curve in the FJ ignitions are hard coded and are shown in the Genuine Factory Service Manual.
Here’s an example



If you want a custom programmable timing curve the new Dyna ignitions will do that via your laptop.
The old Dyna ignition boxes had a selector switch for choosing timing curves.

You could also use the Vance and Hines PowerPak but it's been disconnected for decades and there is little to no support.....

I've got one, probably sticking with the stock ignition, it's not bad.