Tci 180 degrees out???

[Colbycj]

Its an 80 xs650 I turned into a bobber. I've had it running for a few years with zero problem and one day I was out ridding and it just died and started bucking. So I checked out carbs, set valve lash, made sure the cam was in sync with the crank and it was all good. It had spark so I got out the timming light and found out that the timming was 180 degrees out. How the heck does that get out 180 degrees while driving? Any help would be appreciated! Just don't want to start throwing parts at it.


Note some times when I first start cranking it will be right for a few rotations then be out 180.

 

[TwoManyXS1Bs]

Stock TCI ignition?

 

[Colbycj]

Yes it is.

 

[TwoManyXS1Bs]

I guess I'd start testing the usual suspects.

Strength of TCI trigger magnet. Unplug regulator, see if any changes.
Resistance/continuity of pickups.
Connectors and wiring of the ignition system.
Crack open the TCI box, smell and look for burnt things, inspect solder joints.
See if the dog still circles before laying down...

 

[Colbycj]

Do you know what reading you should get when you test the pickup? I'm having trouble finding how to test that. I tried unplugging the regulator and I took a peek in the tci box nothing looked obvious but I don't have much experience with curcit boards.

 

[gggGary]

Pickups; unplug the three wire connector orange then grey to black should both read about 650 to 700 ohms.
Have you done a rotor replacement? How do you know timing is 180 out?
What is your battery voltage both before you try to start it and when running. Are you getting 12 volts to the red wire at the coil?
With the battery charged try unplugging the voltage regulator see if it starts runs..

 

[gggGary]

Any chance the rotor key is missing?

 

[TwoManyXS1Bs]

After doing gggGary's tests, you can also do the forum's "Google custom search" on "test TCI" and "test pickup".

 

[Colbycj]

Awesome! Thanks guys! I'll ohm it out tomorrow and see where I'm at then. I know it's 180 degrees out because when I hook my timming light up it shows the timing mark on the complete other side. I rebuild the top end when I turned it into a bobber but i never took the rotor off.

 

[fredintoon]

Hi Colby,
if you are certain sure the ignition timing is 180º out,
that is, that the spark happens just before BDC instead of just before TDC,
my first thought is that the flywheel key has sheared and the alternator rotor has turned on the crankshaft.

 

[gggGary]

My thought for the day... Does your timing light have an advance setting dial, is it set to zero????? I keep running around the idea that is nearly impossible for the timing to show off with a timing light, no matter where the rotor is in relation to the crankshaft/cam the trigger magnet and timing marks are both ON the rotor!!! Can we see a pic inside the LH round cover please?