TCI system worth replacing?

[abert]

Hey all, I'm new to the forum and have been reading a bunch and don't see much about the TCI ignition system in particular.

I just picked up a 1980 xs that has been mostly stripped and caffe'd. It ran well when I got it, carbs recently cleaned, and I have been riding it for about a month.

It started backfiring more and more when heavy throttle was applied, then on one ride it died when put under load at a stop light. It would not start again until the next day and would only idle, then backfire and die out when put into gear.

From what I found, it seemed to be the symptoms of a failing coil that would completely cut out when hot. I have since checked all the connections and tested the coil, which seems to be okay at 2.5 ohms and 12.5k ohms. The coil, however, is a replacement off of a CB (aw82-tri coil).

Ive only worked on points bikes so I'm not familiar with the TCI system.. Is it worth it to keep the TCI system and buy a new stock coil, or should I fork up the cash and redo the whole ignition system with an advance assembly? Any other experience or recommendations about the TCI system would be great too. Thanks!

 

[jpdevol]

IMO the TCI is worth keeping unless you want to fork out $700 for a VAPE (have both). Any Honda style MP08 coil is a worthy replacement, but yours test good. As with any transistorized ignition, the TCI needs good voltage (good battery and connections with minimal voltage drop).

Attached are some other tests for your TCI system

 

[nj1639]

Not much goes wrong with the TCI, but when something does it's repairable - so far - and there's a lot of gray matter that has been invested to find replacement or alternative parts and pieces from other sources. I'd stick with it, fact I've converted my '77 from points to TCI......one of many instances of where parts bikes are invaluable......

 

[jetmechmarty]

I've been riding my TCI bike for 40 years and 65,000 miles. The charging rotor had to be rewound about 20 years ago. I had a pickup coil failure that happened before MMM owned 650 Central and I bought a used one from whoever it was who acquired it from Johnny Zelna. That's been a long time. About 4 years ago, the TCI box failed. The bike limped home. I sent it off and had it repaired. (not expensive) My ignition coil is original. I've got a '79 bike going together as TCI. I'm of the opinion that the OEM parts are of better quality than most of what's available aftermarket. If it ain't broke, don't fix it!

 

[Wirenutt]

Have you checked valve lash? Tight valves will act similarly to what you describe.

 

[gggGary]

Do you have a voltmeter you can see while riding? My first suspect is a charging system that isn't.

 

[JJames]

Do you have a voltmeter you can see while riding? My first suspect is a charging system that isn't.

Yup...

 

[gggGary]

I happen to know a guy near you can do a diagnosis. He'll be indisposed for the next few days but then maybe?
@Jim

 

[Jan_P]

Do you have a voltmeter you can see while riding? My first suspect is a charging system that isn't.

If voltage is OK I would check what is going into Coils and TCI box and service downstream to ground also

 

[abert]

Hey everyone, thank you for the great responses! Went back through it all. Voltage while running was 14v, coil seemed fine, traced back to a bad connection between the fuse block and the TCI block. It must have rattled loose causing a weak intermittent spark.

 

[nj1639]

Hey everyone, thank you for the great responses! Went back through it all. Voltage while running was 14v, coil seemed fine, traced back to a bad connection between the fuse block and the TCI block. It must have rattled loose causing a weak intermittent spark.

I've learned soldering mostly because of things like that........

 

[sparky4123]

I have converted 3 older bikes to the TCI ignition from the 80+ (Along with building a simplified wiring harness) and all three have run flawlessly. They start easier than my other bike with an aftermarket electronic upgrade.