TCI Replacement 2020 It Works

It's 91 degrees in my office right now so not in the mood to stay in there long but I bet if I were to superimpose a degree wheel on the photo of the tci rotor the magnet is offset from being 180 degrees across from the timing mark is 180-35 35 being the full advance. In other words the magnet passes the pickup at the point of full advance and the the igniter box waits x microseconds before ungrounding the coil to cause the spark x being determined by rpm.
Whew that was a long sentence to explain a quick thought.
 
Wild speculation follows, possible rabbit hole embedded here.


Looking at the stator cover, the hole in the cover above the brushes may be big enough to mount a second pickup for a 277 engine. I know little about the re-phased engines but if the trailing piston fires 83 degrees after the leading piston I think it would work. Would take a little tinkering to get it all the angles lined out.

Re-phased setup
modified stator cover for second pickup.
Magnet in rotor if not a TCI rotor.
2 Gonzo igniters
2 stock 70-79 stock coils or 2 3+ohm aftermarket coils

Comments welcome.

Edit Thinking about wasted spark won't work with one magnet. This would require a separate magnet for each cylinder.

Perhaps a magnet in the stripe between the brush tracks.
 
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Wild speculation follows, possible rabbit hole embedded here.


Looking at the stator cover, the hole in the cover above the brushes may be big enough to mount a second pickup for a 277 engine. I know little about the re-phased engines but if the trailing piston fires 83 degrees after the leading piston I think it would work. Would take a little tinkering to get it all the angles lined out.

Re-phased setup
modified stator cover for second pickup.
Magnet in rotor if not a TCI rotor.
2 Gonzo igniters
2 stock 70-79 stock coils or 2 3+ohm aftermarket coils

Comments welcome.
I've been ponderin' that. Looks doable.. but would need a second magnet in a different orbit from the first so each trigger has it's own magnet. Might have to modify the stator some, but I think it's workable.

big view.jpg
 
Could the center of the magnet be easily defined by scribing two arcs from the centers of two screw heads. Possibly the two screws at approximately 120 degrees from the position of the magnet?? It would require digging some epoxy out to expose the heads.
 
Is the fact that the original magnet is embedded into a copper extension tab from the outer slip ring of any significance?
I've wondered the same thing. I think we are gonna find out soon.I suspect the copper surround is to suppress electrical noise in the pickup coil.
Yes, the copper blocks some of the magnetic field of the coil. I found that out during my rotor rewinding experiments. These magnets I've got have a lot more magnetism than the TCI magnet. I'm hoping we can have the sensor further away so it's far enough out of the alternators magnetic field.
Worst case, I've sourced some .010" copper sheet.... but that would mean removing the slip ring plate. That means a rotor rebuild, so I hope that we don't have to go to that extreme. We'll see.
Look towards the end of this video. It clearly shows the rotors magnetic field being blocked by the copper. Starts about 1:50

 
So for those of you keeping score, the magnet looks to be right at 150° from the timing mark.


150 deg.jpg



Rotor's rebuilt and ready to be modded. I'm waiting for a 1/4" end mill bit to show up to do it. Supposed to be here Sat.


rewound rotor.jpg
 
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Jim, maybe a little lathe project.
1/4" plate,
Drill a 1/2" hole in the center,
Bolt thru that hole, chuck it up, turn the OD to match dia of rotor plate,
Switch over to OD jaws, chuck it up,
Bore the 1/2" hole to 24mm, or whatever the rotor nose dia is,
Locate and drill the 1/4" hole where the magnet goes,
Clamp it (using rotor puller) to a rotor, lining up the magnet and hole,
Scribe or notch aligned with timing mark.

Presto, a drill guide for magnets...
 
Jim, maybe a little lathe project.
1/4" plate,
Drill a 1/2" hole in the center,
Bolt thru that hole, chuck it up, turn the OD to match dia of rotor plate,
Switch over to OD jaws, chuck it up,
Bore the 1/2" hole to 24mm, or whatever the rotor nose dia is,
Locate and drill the 1/4" hole where the magnet goes,
Clamp it (using rotor puller) to a rotor, lining up the magnet and hole,
Scribe or notch aligned with timing mark.

Presto, a drill guide for magnets...
Yeah... thought about doing that... 2 of 'em maybe, one for me and one as a loaner tool.
 
This is incredibly promising. At the risk of coming across as a skeptic, does anyone actually have the DR250 ignition fully installed and running well on their XS yet? I'm really curious how it'll perform with the advance in a real world running scenario.
 
No. Still in the development stage. It's been in the mid to high 90's the last couple of days. I hope to go in a little while and finish mounting it up and getting it wired in permanently. Do hope to get is started and running again. Old Brown is still aways from riding down the block to test it out. Jim has a running bike to put it on so we should know something soon. Trust me, I'm skeptical too but all the results so far have been right where they needed to be.
 
No. Still in the development stage. It's been in the mid to high 90's the last couple of days. I hope to go in a little while and finish mounting it up and getting it wired in permanently. Do hope to get is started and running again. Old Brown is still aways from riding down the block to test it out. Jim has a running bike to put it on so we should know something soon. Trust me, I'm skeptical too but all the results so far have been right where they needed to be.
My box is supposed to be here next week. I'll temporarily put it on the SG and see what happens. If it works, I'll order the connectors for the pigtail and put some miles on it for some first impressions.
 
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