Jumping Tach & Bogging.

[Superfly]

Well, got my 83 carbs working again, Cleaned, synched, and set the air fuel mixture, ran like a champ (not just good, real good!) for 60 miles this morning!!  Then (with a vision, there is always a then!) When I hit city traffic, I noticed that at lower rpm's (and after being ridden for an hour) she would start bogging down, the tach would jump around, and I could hear popping in the pipes.  It seems to be electrical, like a plug going out (it is time to change them) or a bad wire/cap or even a coil.  The charging system is great, she keeps on reading @ 13.9v throughout the whole ordeal (Rev limiter is cut, sidestand is cut) Has anyone had this happen before?

[jasonm.]

if the tach is bouncing like it seems at a low rpm or idle. It could be the ignitor or  the wires to the coil or from the flywheel pickup. I believe the tach is driven from a signal to the rear cylinder. Someone correct me if I am wrong on which cylinder. It is defintely a problem in the ignition somewhere.

[QBS]

Clean your low voltage spark coil connections.  One of them feeds the tach its' signal.  Cheers.

[Superfly]

Thanks for the responses guys.  It did it again this morning.  I replaced the Ignitor last night (got home to late to do anything else!)  I am going to the cycle shop after work and getting some new plugs/wires/caps and swapping out the coils with another set I have, plus I have went 20k plus miles without cleaning/checking any electrical connections by the coils, so it is time.

[Superfly]

Update.

Well, this weekend I have put in new plugs, wires, caps, and swapped out the coils, and swapped out the TCI.? She is really screaming when I am on the open road, but is not fixed yet, still have some major popping in the exhaust (mainly during deceleration, start up, or "engine breaking") and the tach will still jump around.? Stator is fine, and is chargining perfectly.? I have not found the low voltage spark coil connections, because I do not know where they are!? any help would be appreciated.?

I am overdue for a valve job, so I have a feelin' that I am gonna take her off the road and do it. 

The last thing I am thinking it could be is the pickup like jasonm said.? are they available new?

[Lucky]

by low voltage coil connections, he means 'regular' 12V connectors on the coils.

[Superfly]

Oh, I cleaned those connections when I swapped out the coils.  I am about 80k miles deep in this engine, so I guess It is time to just do it... (damn!) I guess I will fix that exhaust bolt while I am at it.