Need Help Identifying Iginition

JCE

XS650 Enthusiast
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I picked up a 1980 xs650 project bike a couple months ago and have been working through the bike to get it running/tuned. I'm just now trying to get familiar with the ignition systems on these bikes but after looking through threads/pics in the tech section here I'm not sure what to make of the ignition system that came on this bike. Here's what I have under both cam end covers, alternator cover, and pic of my coil. Also, the other ignition components consist of R/R, Ignition Unit, and battery. Any help ID what I have would be very appreciated.

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That appears to be a TCI (Transistor Controlled Ignition) setup. Follow the wiring around there should be a black plastic box somewhere with the control unit in it.
 
Yes, stock factory TCI, as used on the 1980 and later models. The coil looks like a newer replacement, probably an aftermarket copy of the original. I'm not crazy about those in-line crimp-on splices on a bike. Bikes, especially this one, vibrate too much.
 
The TCI black box is located underneath the battery box. It can be accessed from the right side by squeezing in past the rear wheel after removing the black plastic section of the rear fender which is held in with 3 bolts. The multi-connector from TCI to the harness will be on the left side behind the side cover alongside the rectifier/regulator multi-connector.

In the alternator photo the black box contains the pick-up coils to trigger the ignition. This pick-up usually never needs to be moved, this is why it does not have conventional screws holding it in place. The 81 version could be unscrewed but again this is usually never required. Once the timing is set it was assumed to be set for life. On the alternator rotor by the two copper rings is an embedded magnet for triggering the pick-up coils. This magnetic will be very weak now so if you get trouble with the ignition come back to the forum and you will be able to find out how to test for a weak magnet and how to replace it.

The timing plate on the alternator has two regions: The right most line with a "T" to its left is TDC. The sort of U shaped mark to the left side is where the ignition should fire at an idle of 1200 rpm. There is no full advance mark because the TCI automatically takes care of the ignition advance based on where the timing at idle is set.

I must say someone has put a lot of work into your bike and engine - Very smart looking!
 
Yes, stock factory TCI, as used on the 1980 and later models. The coil looks like a newer replacement, probably an aftermarket copy of the original. I'm not crazy about those in-line crimp-on splices on a bike. Bikes, especially this one, vibrate too much.

The entire (re)wiring on this bike was done by some real monkeys for sure. After getting the bike tuned to where I'm happy I plan to build my own marine grade harness. For now I just cringe.:laugh:
 
The TCI black box is located underneath the battery box. It can be accessed from the right side by squeezing in past the rear wheel after removing the black plastic section of the rear fender which is held in with 3 bolts. The multi-connector from TCI to the harness will be on the left side behind the side cover alongside the rectifier/regulator multi-connector.

In the alternator photo the black box contains the pick-up coils to trigger the ignition. This pick-up usually never needs to be moved, this is why it does not have conventional screws holding it in place. The 81 version could be unscrewed but again this is usually never required. Once the timing is set it was assumed to be set for life. On the alternator rotor by the two copper rings is an embedded magnet for triggering the pick-up coils. This magnetic will be very weak now so if you get trouble with the ignition come back to the forum and you will be able to find out how to test for a weak magnet and how to replace it.

The timing plate on the alternator has two regions: The right most line with a "T" to its left is TDC. The sort of U shaped mark to the left side is where the ignition should fire at an idle of 1200 rpm. There is no full advance mark because the TCI automatically takes care of the ignition advance based on where the timing at idle is set.

I must say someone has put a lot of work into your bike and engine - Very smart looking!

Really good info, thank you!!
I'm trouble shooting a miss at low rpms that I suspect is ignition related. I've already tuned the carbs and actually had the bike running perfect for a couple rides through the entire throttle range, then during the latest ride the bike decided to miss/stumble just off idle to about 2k rpm before it stayed lit and pulled hard. Need to test each ignition component to gain confidence in what I have before I go any further.
 
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