I'd had 'strange' tach issues for two years, where the tach would briefly go to 0 and the engine would run sluggish, then return to normal along with the tach. About 3 weeks back, the tach went to 0 and stayed there and the engine was clearly running on a single cylinder. This lasted for about a minute then the engine ran normally. Same thing happened the next two times I rode the bike. I swapped in a spare TCI, which replaced the problem with similar ones.
I purchased a non-programmable TCI from Ingnitech, installed it, and have had no problems since. Performance is the same as it was with the OEM units.
I think my 40 year old TCI and similarly old backup are past their useful ives. But the new one seems to be working great.
That is reassuring news! An 'ace in the hole', so to speak. So many original parts are no longer available from Yamaha, so it is reassuring to have access to the IGNITECH.
Yes reassuring and I am hopeful that the unit installed will turn out to have 'fixed' the problems I was experiencing. Not enough time on the bike yet to say for certain, and given that it's now raining in Seattle for the foreseeable future, it may be a while before I can claim victory. But good so far. Ignitech was easy to work with. Not cheap at about $170 including shipping from Czech Republic. And it took a few weeks. The unit is a different size and shape but was easy enough to zip-tie in place behind the cover.
Hoping this will help others!
I'm glad you tried the Ignitech. I've long believed it would work and would have gotten one when my stocker failed, and it will.
"Raining in Seattle" !! I wish it were raining here in northern California. However, our weather is just gorgeous now! Warm enough to wear a T shirt, and cool enough to wear long sleeves comfortably. You can be comfortable wearing a heavy jacket for riding as Summer has gone now. This is Autumn, and Winter will be here very soon.
I celebrated my 78 birthday with some dear friends/inlaws, had a great lunch at the Auburn airport Wings cafe. They have reliably good food, but are only Breakfast and lunch, no dinner. (day light hours)
Current update:
I have not had a recurrence of the problems experienced before installing the new TCI unit. I had a different problem once as follows:
Bike warming up in the driveway in the normal fashion, then tach dropped to 0 and engine ran on one cylinder. I turned it off, let it sit for 5-10 minutes, and re-started it. Problem was gone and has not returned. While tis is similar to the problem that led me to buy and install the new TCI, it is definitely not the same. Maybe I've got a coil problem? The rev limiter circuit was cut when I got the bike, so I don't think that is causing this.
Possible issues: plug wires/caps, wire connections on offending coil, . . . . . ummmm . . .it's gotta be something. Can you tell which cylinder is misfiring?
It has not happened again, but if it does, or I guess when it does, I will check the exhaust to see if there is a difference between the two sides. I recently replaced the mufflers with a stock set that is cosmetically better and did some scoping. The mufflers are more complex than I figured: The exhaust from the two cylinders is not combined in the crossover. The front cylinder exits through the right pipe, the rear cylinder exits through the left pipe.
FYI, I had the same symptoms (no tach, one cylinder) and installed the Ignitech unit and it has worked perfectly for over a year.
Checking the exhaust out of the mufflers won't really tell you anything as the 2 cylinders merge in the collector. You will have to take a squirt bottle and spray water on the pipes out of the cylinder head. Sizzle is good. You should see a difference.
I think someone will have to cut open a set of mufflers to verify this, but from my borescope investigation, it appears that the the exhaust from the front and rear cylinders do not merge at the crossover.
I have seen a cutaway view of the chamber where the front and rear cyl exhaust go into and there is not a separation between front and rear cyl. They both dump into the chamber and exit out both mufflers. I think it was in the service manual that I saw that.
Had the same problem with tach dropping to zero and running on one cylinder. New spark plug caps cured it. Also I've cut open an exhaust. Rear head pipe runs into left muffler.
So I pushed an electrical cable down the rear cylinder inlet to the crossover, & got it to exit on both the left & right hand sides.
That's not what mine looked like at all. I cut it into pieces as I was building an exhaust system for it which is still on it. It had a pipe from the Y pipe connection that ran well up into the left muffler. From there it could communicate with the collector as that area was quite spacious and open. I was mainly interested in the apparent shortness of the rear head pipe which turned out to be longer than was apparent. Should have taken pictures, but this was pre cell phone so not so convenient then.