TCI Replacement 2020 It Works

[thuban]

I'm not convinced. The pickup is a hall effect switch operating in a magnetic field. It does not see the field. No current is induced in the hall effect switch by the magnetic field of the alternator. The switch is running blind and smooth until it approaches and runs across the copper shielding and hits the magnet. The magnet is a "bump in the road". That bump induces a voltage/current read by the box. The screw heads would be a hole in the road possibly N. . Magnet should be south pole facing out as most switches of this type work on the South pole. I don't know, I'm just saying.
"....I suspect the magnet is placed so it is opposite the magnetic field of the rotor." I'm betting your right!
I'll almost bet money, that when we think the magnet has lost it's strength it's really the pickup winding degraded. By putting in/on a stronger magnet gives the degraded pickup a new lease on life. Quickest way I know of to kill a magnet is hit it or drop it. But I'm not a one-wire, so I don't know.

 

[Team Junk]

I'm not convinced that these pickups involve a hall effect device. I think it is a simple coil of fine wire wrapped around a armature. And the scope captures don't look like a hall device.
Hall effect devices are polarity sensitive and these aren't and the stock one is the same way.

 

[gggGary]

Hey found a pic of the brain trust working this out.

 

[Team Junk]

These guys were firing 1 ton projectiles 24 miles and hitting somewhere close enough to keep the Chinese at bay. I'll take that as a complement.
Maybe not the way I would word it face to face.

 

[nj1639]

Subscribed.

 

[MacMcMacmac]

The pickup is referred to as a coil in the manual, fwiw. I am assuming the output is used as a gate voltage to trigger the tranistorized ignitor output on/off. Would the polarity of the magnet affect the sign of the output voltage? That would be significant depending on whether the transistor was PNP of NPN. Just a WAG.

 

[Team Junk]

Yes on some boxes prefer positive first and some negative pulse first. Gonzo doesn't seem to care. When I first built the simulator I stuck the magnet to the magnet in my tci rotor and glued it (so I thought) in the same orientation and the gonzo fired off of it with the pickup phased ether way it would fire. Only when I hooked the scope on it did I discover the polarity was reversed .

In looking at all the systems for motorcycles looking for a box that would work, the pickup is almost always referred to as a coil with an impedance spec in a lot of cases.

 

[Team Junk]

And I notice the Ebay seller selling the pickups raised his price also.

 

[Team Junk]

thuban
Looks like pretty disturbed weather your way. Keep your head down.

 

[Team Junk]

I'll almost bet money, that when we think the magnet has lost it's strength it's really the pickup winding degraded

I wouldn't take that bet. I think your right. The development by Jim to convert non TCI bikes is that the components of the ignition system that are 40 years old with newer parts. I'm especially concerned about the hi current and heat coils in the rotor and stator.

If I planned on traveling any distance on Old Brown I would

Have Jim rewind the rotor
I guess a repop stator.
Solid state regulator. The alternator on the 650 only puts 2 amps of current through the regulator vs. 10 or more amps a PMA generator deals with.
Repop or oem Honda coil.
Oh and of course new brushes

That would go another 40 years

Sure wish Jim was rewinding stators.

 

[Jim]

Sure wish Jim was rewinding stators.

Not sure why, but these XS stators hardly ever fail.

 

[thuban]

Yep, TJ, rain for a week! Yes, I think the magnet induces a current in the coil of the pickup to the gate of the SCR triggering firing. I wonder what the reading would be by sweeping a magnet over a pickup? It would show on the O-scope.

 

[Team Junk]

 

[Team Junk]

Wired into Old Brown just pushing the kick starter through to a compresson stroke will fire the box. 39 year old magnet and dual tci pickup.

 

[thuban]

The pickup looks like it's dual but three wires? One ground, one power and one signal? ( I read that one of the "Pips" on the pickup was for figuring advance, the other for firing.) Looks like both "pips" may be energized at the same time and the TCI box knows ( when the magnet passes under) when to fire at the first "pip" and the time ( rotational speed) between "pips" to figure advance. ( Unless the case is ground, one power and two signals.) My moneys on the former. Old Brown is a good one! This is looking better and better!

 

[Team Junk]

Two coils center tapped. I'm at a disadvantage because I have never had a stock tci box so I don't know what it acts like when advancing. It appears it switches from the idle pickup to the advanced pickup . Don't know how it works. I have no idea if advances smoothly or jumps. It was one of the first TCI boxes and they improved rapidly from there.

 

[thuban]

I don't have a TCI either. I have an 81 engine as a spare. It's supposed to run. Compression is good.
I have to think it fires at the first "pip" then measures the time to the second "pip" and schedules advance based on that time. RPM increases and the time between "pips" decreases. Probably a smooth advance. I don't know but it makes the most sense to me. I'm looking for a cheaper TCI box but they are high.

 

[gggGary]

Hey jim etal I have thought of this a bit before.... yah know...
you have a rotating assembly (shaft nut washer that stick up above the stator frame your new pickups are set for side fire would not be very hard to design, build a reluctor that was clamped to the shaft by the nut. A drilled hole in the XS650 rotor to key it for timing?

Since the radian is a 4 cylinder you get an extra pickup AND the TCI has a complete extra ignition circuit..... It's a more advanced TCI with a single Fire magnet..
Downside: These are NOT as common as the Zooky but that motor was used in 4 or 5 Yamahas of that era as 550 and 600 4 cylinder.
Part #2 rotor, pick ups, and ignitor box were used in 600 FJ, FZ and the YX Radians 84-88

 

[Jim]

build a reluctor that was clamped to the shaft by the nut. A drilled hole in the XS650 rotor to key it for timing?

Might be doable... but there's very little room 'tween the nut and the brush holder.

 

[nj1639]

It's great to see the gray matter trust at work. I've wondered where things may go since mr. Rigg's posted about the automobile ignition and the need to retard it on startup iirc. That got the wheels turning about mounting the pickup with a spring setup which might be doable, but then the need of another cable and actuated. The '82 and '83 Heritage model chokes come to mind as I type.