Diagnostics: Ohm reading for TCI pick up coils

[Pat Conlon]

Thanks Guys...!

Hooli, yep, when I put the Dyna cables on I had to convert over to the screw on plug tips,,,I made sure those puppies where tight.

Thanks Mark, I'll disassemble the kill switch and clean it...it's been several years since I've done this...good reminder. 


....to be continued

[Flynt]

Sometimes (most of the time) it can be the simplest of things....wouldn't that be something?

Wizard needed a strong dose of Techron and new plugs at 10K...  at least that was the first interval with the 1350.  I talked to Randy suspecting something bigger as it was not acting normal...  down on top end power with a "lean feeling" (studder?) at higher RPMs.  I'm at about 17K now, so we'll see if it comes back soon enough.

Frank

[ct7088]

Does the stutter occur at a constant RPM or only when accelerating hard? The things i suspect on a miss under a high RPM load are the coils, plug resisters or plugs.

[Pat Conlon]

Thanks Frank, that's good to know about the Wizard. Did the plugs look abnormal?

Chris, the ignition studder is momentary and clears quickly as the RPM's continue to rise, around 7.7~8k range. I also notice a fluctuation in the tach needle when this happens.
If it was a fuel delivery issue the tach needle would stay constant.
Definitely ignition, no doubt in my mind.

We shall see with new plugs.

[ribbert]

I also notice a fluctuation in the tach needle when this happens.

At last, a clue. If the tacho needle is bouncing in synch with the miss, it's getting an electrical interruption to the power supply and I would start by hunting around some of the primary wiring.

With motor running, push, pull, tug, drag etc all the wiring you can access and see if disturbing it causes the miss at idle.

Electrical problems: 2 days to find, 2 minutes to fix.

Noel

[Flynt]

Did the plugs look abnormal?

Pretty much...  even color across the 4, slightly more carbon than you'd want (FCR accelerator pumps I suspect) but nothing that would make me change them.  I did the tune-up as first step of diagnostics and the issue went away immediately.  The Techron booster (I normally run Chevron fuel, but I added the concentrate as well) was added to ~1/2 tank and I rode ~5mi to top off the tank.  I then rode about 150miles and Wiz was back to normal ferocity by the end of it.

I had the jumpy tach needle issue pre-rebuild and never really found the cause.  During the build we made sure the coil ground was done right and the tach has been happy since...  maybe coil grounding could be your issue?

Frank

[fj1289]

I also notice a fluctuation in the tach needle when this happens.

At last, a clue. If the tacho needle is bouncing in synch with the miss, it's getting an electrical interruption to the power supply and I would start by hunting around some of the primary wiring.

With motor running, push, pull, tug, drag etc all the wiring you can access and see if disturbing it causes the miss at idle.

Electrical problems: 2 days to find, 2 minutes to fix.

Noel

Pat - I'd consider temporarily taking the coil relay mod off and doing a test run.  Or - replacing with another relay.  The mechanical points could be reacting to the vibration at that particular RPM range -- especially if the relay has been in for a while.

Also - what carbs?  CV's?

edit -- OOPS - see where Hooli went there already!

[Pat Conlon]

Thanks Noel, yep that is the drill, yes, partial connections are tricky to find..
You really need a ohm reading to show up...a continuity light or buzzer won't cut it.

Frank, that was first on my list to rule out, the ground. All connections are scrubbed and clean.
There is a dedicated ground (along with power) home run back to the battery when the coil relay mod was done.

Chris, yes, still on the CV 36's.
Randy is working on re-spacing a set of GSXR750 Slingshot 38CV's I will experiment with this summer after the WCR and Central Rally.

I'll plug in a fresh relay, just because I have it....(same 30a relay as my headlight mod, I always keep a couple of spares)

[fj1289]

Pat - asked about the carbs - wondering if something is causing one or more slides to "flutter" at that point (creating a lean stumble) and then pulls through it?  Also, how's the battery?  I've had one start to go bad that would cause an ignition miss before it showed any other signs. 

Chris

[Pat Conlon]

Carbs are good. Clean. Diaphragms good, slides move freely and drop equally.
Battery is 2 years old. Starts fine. Hot starts fine (XJR starter) Battery voltage good.

[Mark Olson]

Pat,

It is 10am now , haven't you changed the plugs yet?

[Pat Conlon]

Had to work (kind of) yesterday..

So this morning, fresh plugs, recleaned the 2 TCI plugs and the 2 connectors to the coils, new coil relay and cleaned the handlebar run/stop switch....the bike starts and purrs like a kitten, a 15 mile warm up then a Kookaloo blast down my favorite deserted desert road and....the studder is still there...barely.

Very slight studder at 7200 then pulls cleanly thru that all the way to 10k. Still the bike runs very strong.

So to recap, since the start of  the symptom:
1) new Dyna 3 ohm coils wires boots and plugs.
2) ohm checked the pickup coils. Ok at 160 ohms (thanks again Coop, Randy) Values in Clymer/Haynes wrong.
3) swapped in a different TCI
4) new coil relay.
5) cleaned run/stop switch, 2 TCI and 2 coil connector plugs. Ohm checked and wiggled coil signal wires from TCI to coils.

Next on my list is to pull the tank again (sigh) and disconnect the tach leads at the coils. Perhaps something goofy is going on with the tach?

Either way it is a very very slight studder, not really a big deal but still...its ttthere...and gone in a flash.
I don't spend a lot of time riding at 7200 rpm.


The search continues...

[aviationfred]

A thought here, 

Install a known good set of OEM coils and make no other changes, take it for another romp through the canyons.



Fred

[ct7088]

Pat, the bouncing tach could mean a voltage supply problem. I followed Aviation Fred's link and purchased a 84/85 wiring diagram that shows the harness connectors but that will take a week to arrive. Probably a harmonic from the engine vibration at 7.2K.
Chris 

[Pat Conlon]

Fred, the oem coils I took off tested fine...I had the Dyna greens laying around the work shop for 5 years so I figured, what the heck...

Chris, no bouncing of the tach needle, nothing big like that.. just a little flutter at 7.2k then normal readings as the bike flat boogies to 10k.
I think you may be on to something re: harmonics. It happens exactly at (according to the tach)  7.2, not 7.1 or below...or 7.3 and above.
After I disconnect the tach to what happens...my next move is to remove the fairing and start pulling plugs apart.
If the coil relay was the culprit or the (ignition switch) power supply to the relay coil, the power interruption would be dramatic...both coils would be affected. This is not the case.

The next move after that, will be running 2 new coil signal wires from the TCI to the coils....and after that, replacing the coil pick ups with my back up set.

I want to do this one step at a time to see what brings the desired results.... As Noel said, 10 days to find the problem, 10 minutes to fix.