Hi everyone, I have a Yamaha XV 1000 TR1. When I start the bike and give it some throttle, it begins to backfire.

What I’ve already checked:
     •      Spark plugs
     •      Plug wires
     •      Ground connections

The bike has been modified – the carbs were drilled, and it doesn’t have the original air filter.

Question: How can I check if the TCI unit (ignition module) might be the issue?
Has anyone experienced similar symptoms with this model or setup?

Thank you!

Quote:

The bike has been modified – the carbs were drilled, and it doesn’t have the original air filter.

Perhaps thats the reason...


Quote:

How can I check if the TCI unit (ignition module) might be the issue?

Try another one.

Hey There Audrius92,
Are the Ignition Coils connectet to the correct cylinder?

You can check the firing range at the left Crankcase cover, with a lighting Pistol
Use Cylinder #1, the rear, and the Fly Wheel Marking "F" . The "F" for Firing shows you a gab of a few degrees in wihich your Igniion shall operate.ß
See Maintenance Manual , https://www.tr1.de/pages/technics_manual.php?key=XV750se&lng=eng&flg=0&pge=2021

Notice:
do not change anything on the Carbs, only to renew Parts with original Parts or similar.
To get a sadisfieng solution with "tuned" Carbs is highly risky. To adjust such Carbs take time and need a lot of passion.

Try to get an other set of Carbs. If the engine is running proper with them, keep them installed.
The TR1 was never a speed wonder, but a relaiable Tourer, with good punch, if well maintained.

Kind Regards
Anja

Hi Audrius,

easiest ways to check whether your TCI works (unless you have a known good one available to you):
* check for spark on both cylinders. Take a spare spark plug put it in the boot and hold the spark plug firmly to the cylinder so the metal section, but not the electrode, and it should spark
* check if your tach works. In a lot of the TCI boxes I repair the tach was very jumpy, because it was leaking voltage inside the box. (Unfortunately the tachs aren't overly reliable, so that's not the best test.)
* last but not least swap the two connectors that come down from the loom and  go into the coils in the headstock area.



Anja-D wrote:

To get a sadisfieng solution with "tuned" Carbs is highly risky. To adjust such Carbs take time and need a lot of passion.

Let's not turn a mouse into an elephant, it's not that hard. Just requires a bit of dedication and methodical work.


Anja-D wrote:

The TR1 was never a speed wonder, but a relaiable Tourer, with good punch, if well maintained.

Mumbles then name "Sepp" ;-) - actually the TR1 has a lot of potential, it's just being locked up very well in stock form. :-)

Cheers,
Greg

Thank you for trying to help me.

I’ve been struggling with this bike for 3 years. It’s been to 3 mechanics, and none of them can find the problem—or maybe they don’t want to, I don’t know. So, I decided to take things into my own hands, even though I have zero experience with motorcycles 😁

Anyway, I’ve checked the timing. The rear cylinder is aligned, but I’m not sure about the front one.
Also, the spark plug from the front spark plug is black compared to the rear one.

https://www.directupload.eu/delfile/SkdScnJXQUZ5aFVTVDA3ZHpXZit6dz09/

https://www.directupload.eu/delfile/REZ1KzRIZm91K3QyOTVIQytYbGtOZz09/

Hey Audrius,
well, ok, before turning the "big Wheel":
Do you have renewed the Spark plug connector and the Spark Plugs it self? or the Ignition Wires?
Does the Ignition Cables are sitting proper on both Sides
a. in  the ignition Coil and
b. in the park plug connector
c. does the Ends of Ignition Cable are in got shape (all wires are present? not good are only a few of them, perhaps)
If not all wires ae visible, cut off a pice of the ignition Cable to solve)

Regards Anja