New TCI module?

[Mickey85]

OK, I've gotten the carbs fixed, and discovered that the problem with one cylinder not running is an electrical issue.

Doing some ham-fisted testing, the coil will build a spark about 1/2" long from the end of the wire to the cylinder, and if you hold the plug wire a bit off the plug, it'll spark, as the spark is built off the end of the plug and not within the plug. I've swapped plugs, replaced plugs, and that's not the issue.

Doing research, I've seen that a single-cylinder misfire and occasional firing can be caused by a bad TCI, but I've also seen that there isn't really a place for new TCI's. I haven't pulled mine out or tried to reflow the solder yet, but a quick search on Ebay has led me to this...

http://www.ebay.com/itm/REGULATOR-R...NEW-/290798826230?hash=item43b4f5f2f6&vxp=mtr

Is this a real thing???? If it would work, that'd be a $35 I'd be willing to spend just to eliminate that as a potential problem area.

And, before it's mentioned, of course I plan on testing the coils as much as possible to eliminate them. If they're not getting a solid signal though, they would give a bad reading, and I'd rather not spend $100 for two coils and a TCI when I can drop $35 for just the TCI and fix the problem.

 

[xschris]

That's not it. http://www.ebay.com/itm/1981-Yamaha...02C-/351243910725?hash=item51c7c4be45&vxp=mtr This is a TCI box. The other is for the charging system. If you have spark on both plugs then I would look at a weak coils. Test the coils and get new wires and caps.

 

[Mickey85]

Well poop.

Also, it decided to run on both cylinders today...on a related note, I think I went too rich for the main jets, as the fuel supplied by my rebuilt dead peacock (which just dumps fuel no matter the setting) will drown the right cylinder and cause it to stop firing. Pull the fuel line and let it run off the float bowls and it picks back up. I'll probably jet down again once I make sure the electricalsystem is not an issue.

 

[Wolfe_11B]

Check your connecter coming from the coil. Clean the contacts, check the wires, etc

 

[BBS360]

as the fuel supplied by my rebuilt dead peacock (which just dumps fuel no matter the setting)

The bike should still run ok with the petcock dumping fuel as it's the carbs that regulate fuel.
The jets could be overly large but if the carb float bowls are overfilling you might want to check float height and verify that the needle valves are sealing well.

If they're not getting a solid signal though, they would give a bad reading,

Just in case there's a misconception here, coil tests are resistance tests done when all bike power is off. As the bike is off there is no "signal" that would artificially produce false bad readings in the coils.
As long as you have an accurate meter you should be able to do accurate tests of the coils.

 

[Mickey85]

Ok.
A. How does one seat the needles? I pulled the needles and the tubes they go into (can't remember the name offhand), and cleaned both, ensuring they're both clean, tarnish free, and appearing to do their job.

B. I'll check the floats

C. There's nothing wrong then with running rich jets, assuming everything else is ok?

D. I have a CSM, but it's from a bike with points. Is the coil test the same as described in my CSM?



I've named this thing "lil bastard" already.

 

[BBS360]

Ok.
A. How does one seat the needles? I pulled the needles and the tubes they go into (can't remember the name offhand), and cleaned both, ensuring they're both clean, tarnish free, and appearing to do their job.

That's about all you can do short of replacing them. The o-ring or gasket around the needle valve seat should be in good condition.
My non-scientific test was to blow through mine while applying only slight pressure to the needle and couldn't get any air through.

C. There's nothing wrong then with running rich jets, assuming everything else is ok?

I haven't properly tuned my carbs and jets yet so I'm sure someone can give a better answer but an overly rich mixture will affect fuel economy, idling, foul plugs, and generally keep the bike from running most efficiently.

D. I have a CSM, but it's from a bike with points. Is the coil test the same as described in my CSM?

I believe the procedure is the same but I don't know whether the specced values are the same. They must have been posted on here at some point. Try the search tool. Might even be a manual to download for TCI bikes with the values.