1981 XS1100 Midnight Special Slow restoration

[bikerphil]

The first picture in post #36 shows where the P/U coil connections are, make sure there is no broken solder joint there. There is a red circle identifying the 4 connections.

[Medumdum]

Finally got a new battery in a few days ago, trickle charged it overnight and still the same, still only spark on 1-4, even when switching coils, pickups. Did a oil change and ngk plugs while I was waiting for the battery, so those are fresh. I’m pretty sure it’s the TCI by now, but I have no idea what I’d need to do to repair it. I’ve done soldering plenty before, but only when someone/something is telling me what to test/solder. I can’t seem to find a guide to repairing the XS1100 TCI specifically. I’m probably going to try and actually open it up now to look at the board, since it looked like I have to desolder the pins to actually get it out of the box.

I’m picking up a parts bike that the PO of this bike offered, no tank or plastics just frame, bad engine and electrical, but hoping the TCI is still good, and it won’t hurt to have spares. Won’t be able to pick it up till next Sunday, so if I can fix the TCI in the interim all the better.

[bikerphil]

Yes, and make sure the battery voltage is up to snuff or the TCI won't fire properly.

[Medumdum]

This is how.

Interesting, I’ll check out the voltages on the TCI make sure they’re good.

[Medumdum]

You mean it may be the ignition coil, you were just testing the pickup coils. Another place to look is the solder joints inside the TCI, sometimes they crack where the 4 pin connector attached.

Ah, thought it just tested the wiring and there was a chance the pickup itself wasn’t picking up the signal from the rotor. When I swapped the coils both sparked, and resistances were all in spec, so I think those both have to be good. I took a quick look at the TCI and nothing looked obviously broken but I’ll try and test those pins.

[DEEBS11]

This is the area.

[bikerphil]

You mean it may be the ignition coil, you were just testing the pickup coils. Another place to look is the solder joints inside the TCI, sometimes they crack where the 4 pin connector attached.

[DEEBS11]

This is how.

[Medumdum]

Unplug the 4 pin connector on the TCI and check for 720 ohms between pairs while jiggling the wires down at the ignition plate. They usually break internally where they are clamped. That video you posted is for a 750, 3 cylinder which is different.

Tried it, jiggled the hell out of all the wiring on the pickup coils and both connections read a constant 730-740 ohms. Even cranked the bike, resistances changed a bit but never went over 1k or dropped below 600. I even checked the resistances of the ground wire to ground on the battery while jiggling the cable, got about 50-60 ohms on both as well. So at this point I’m assuming it’s the pickup coil, but would there be any other way to test the pickup coil itself?

[bikerphil]

I can't recall a triple with YICS. Looks more like a small Maxim or Seca to me. Not that it is important

Yep, you're right Mathh, it is an XJ small 4 cyl.

[Mathh]

I can't recall a triple with YICS. Looks more like a small Maxim or Seca to me. Not that it is important

[bikerphil]

Unplug the 4 pin connector on the TCI and check for 720 ohms between pairs while jiggling the wires down at the ignition plate. They usually break internally where they are clamped. That video you posted is for a 750, 3 cylinder which is different.

[Medumdum]

I just wasn’t googling hard enough I guess, I finally found this video and it showed me what I needed. I just gotta plug my multimeter leads into the connector from the pickup at the TCI and measure the resistance between the ground pin and the orange/grey pins, then jiggle the wire to see if the resistance changes or if there’s a break all together. Sadly I’m at work now so I’ll have to wait till tomorrow to test it properly.

[Medumdum]

More on your spark problem

https://xs11.club/forum/idle-talk-fo...ver-the-winter

Looked at the forum, haven’t finished it but the guy there had no spark at all, so it’s talking about stuff that isn’t really relevant. I do have spark, but only on 1-4. Bike will run, just on 2 cylinders, middle exhaust pipes stayed cold, outer two got hot, no spark on cylinders 2-3. I swapped the pins on the TCI connector that comes from the pickups, still only got spark on 1-4, leading me to believe I have an issue in the wiring of the 2-3 pickup to the TCI or the pickup itself.

I’m just looking for a way to get the wiring off the pickup to test continuity/resistance between there and the TCI to see if I just need to fix the wiring or find a new pickup.

I did test continuity from the TCI plug to the ignition coil connector and both the grey and orange pins do have continuity, so shouldn’t be an issue in that wiring.

edit: to clarify, coils are also both good, swapped them around and both have good spark, but would only spark when connected to the circuit connected to the 1-4 pickup, even when switching the pickup input pins on the TCI connector.

[DEEBS11]

More on your spark problem

https://xs11.club/forum/idle-talk-forum/xs11-xj11-discussion/874809-lost-my-spark-over-the-winter