Mille non corre -- Riparato!

[Testarossa]

Need a wiser head (or two).

My '89 Mille was running strong. Stopped for a light. Idling normally at 1000 rpm. Light turns green. Pulled clutch, snicked into first gear, released clutch, engine died. On restart, one cylinder fired then quit and starter motor continued turning with no fire. Trucked it home to find:

Good spark both sides from Dyna III ignition. Plugs look a bit rich. It's not the kill switch.

Static timing is good and the advance weights function smoothly. It's not the dizzy.

Fuel in both float bowls and fuel lines, full tank. Couldn't be instant blockage in both carbs at once.

12.47v on a new-this-spring battery.

Compression 150 and 145psi (at 5700 feet elevation). Not a valve-adjustment issue.

All electrics work.

What am I missing? What else could cause this engine to quit suddenly, with no fuel-starvation warnings, and refuse to fire both sides while cranking smoothly?

Baffled for now.

[fotoguzzi]

I'm not wiser but isn't there some funky wiring on that vintage where everything goes through the ignition switch?

[RinkRat II]

       Try shooting some starting fluid in and see if it's ignition or not. My $.02

       Paul B

[Groover]

water in the tank/bowls?

[John A]

Ignition switch contacts could cause that

[Don G]

Ignition wiring circuit perhaps, power is fed through the kill switch too?  DonG

[Sye]

Sidestand switch?

[Testarossa]

Not to be snarky, guys, but you may not have understood my first post. To repeat:

There's nothing wrong with the ignition: I have fat spark on both sides, timed correctly.

Therefore it's not the ignition switch. The sidestand switch was bypassed by a PO.

I know the difference between gasoline and water -- and checking the float bowls, it ain't water in there. Besides, the bike ran fine for 40 miles before this happened.

I will try starting fluid.

More ideas solicited.

[TOMB]

Yours wouldn't be the first one the ground strap to the frame is loose and covered with crap.

See if you can move it with little effort.

Happened with my Eldo with sidecar . Intermittent running them cut out .

Shook the handlebars and it would run perfectly.

Give it a try.

TOMB

[bmc5733946]

Spark plugs spark very differently under compression pressure than in open air. I would suspect the dyna although you don't. I won't use one anymore after seeing things like this repeatedly.  YMMV!

Brian

[Testarossa]

Spark plugs spark very differently under compression pressure than in open air. I would suspect the dyna although you don't. I won't use one anymore after seeing things like this repeatedly.  YMMV!

This is a good point and would explain the sudden simultaneous failure. I'll query Dyna about how to text their unit. This one has only 500 miles on it. My 850T has gone 3500 miles on its Dyna III. If it turns out the Dyna has failed, I'm back to points for both bikes.

[centauro]

Your situation is identical to what I experienced some years ago with my '84 SP, which was also equipped with the Dyna III.
I went through the same usual checks you did on your Mille, and came up empty handed.

I finally found the culprit to be the 4-wire molex connector that leads to the engine start /kill switches on the right bar.
The molex terminals were extremely corroded and had mostly melted the molex block.
 I snipped off both sides of the connector, stripped the wires, and reconnected them individually with new male and female bullet connectors. If your wires are color coded the same as mine, the white wire in that block feeds the + ive side of the coils. It runs through the big harness under the tank, out by the rear brake master cylinder, into another conduct behind the battery, and out to the coils. No idea if your coil location is same as mine, though.

What I found was that the severe corrosion in the molex block terminals was creating a high resistance in the wire, which means that the coils (mine were also Dyna) would not get all the amps they needed. That white wire insulation was partially melted until half way to the coils! I replaced the entire wire with a higher gage, 14 awg, and, with the new connections at the molex block all was fine again.
Good luck.

[centauro]

This is a good point and would explain the sudden simultaneous failure. I'll query Dyna about how to text their unit. This one has only 500 miles on it. My 850T has gone 3500 miles on its Dyna III. If it turns out the Dyna has failed, I'm back to points for both bikes.

BTW, the Dyna III and coils setup, with all its good  (and bad) reputation, needs a solid 6-8 amps to operate correctly.
Eventually, as a final improvement, I set up the power feed to the Dyna III and coils via a dedicated relay, fed by a fused (10 A) 14 gage wire direct from the battery. The kill switch would now only serve as the trigger to that relay. This eliminates all the high resistance from the junction/fuse box to the ignition switch to the kill switch to the coils, in that order. As a bonus, you get a fuse-protected feed circuit to to the coils and Dyna, which Guzzi does not originally have, since the points don't really need that protection, being mechanical in design. Other people on this forum have done the same.

[Testarossa]

BTW, the Dyna III and coils setup, with all its good  (and bad) reputation, needs a solid 6-8 amps to operate correctly.
Eventually, as a final improvement, I set up the power feed to the Dyna III and coils via a dedicated relay, fed by a fused (10 A) 14 gage wire direct from the battery. The kill switch would now only serve as the trigger to that relay. This eliminates all the high resistance from the junction/fuse box to the ignition switch to the kill switch to the coils, in that order. As a bonus, you get a fuse-protected feed circuit to to the coils and Dyna, which Guzzi does not originally have, since the points don't really need that protection, being mechanical in design. Other people on this forum have done the same.

This is GREAT info and I'll try that. On my 850T I built my own wire harness with direct power feed to the coils from the fuse box and direct power from the ignition switch to the fuse box -- NO intermediate connectors at all. Will take 20 minutes to rig up something similar for the Mille. Will report back.

[Antietam Classic Cycle]

BTW, the Dyna III and coils setup, with all its good  (and bad) reputation, needs a solid 6-8 amps to operate correctly.
Eventually, as a final improvement, I set up the power feed to the Dyna III and coils via a dedicated relay, fed by a fused (10 A) 14 gage wire direct from the battery. The kill switch would now only serve as the trigger to that relay. This eliminates all the high resistance from the junction/fuse box to the ignition switch to the kill switch to the coils, in that order. As a bonus, you get a fuse-protected feed circuit to to the coils and Dyna, which Guzzi does not originally have, since the points don't really need that protection, being mechanical in design. Other people on this forum have done the same.

  Did that on a customer's V65SP after it melted the (aftermarket K&S) kill switch. Not a bad idea no matter what coils or whether it has points/e.i.

[John A]

I re read the original post, I had  thought maybe the ignition switch momentarily lost contact but now I think I suspect the Dyna. I always carried a points plate and left the condensers on the dizzy when I was far from home. I had to use it once but it was on a Dyna S on a small block 100 miles from home an a seriously hot Sunday.

[bmc5733946]

Electronic ignitions are wonderful things when they are working properly. The Dyna's seem to posses a mind of their own. It seems to me that that is the case for many small companies that make a relatively small number of units to cover a very small market segment. Guzzi points, when you get good ones, are very reliable and work just fine, I think I have adjusted mine once in more than 20yrs of ownership. I do check the timing occasionally but it hasn't moved since I installed a Valtek tensioner quite some time ago. I think a lot of people put a timing light on and see the timing jumping all over and believe it to be a points problem when really it's just sloppy timing from a loose timing chain causing the camshaft to not drive the distributor accurately and smoothly. I am sure that now I have expressed my confidence in my ignition system,  it will fail me in fairly short order!

Brian

[redrider90]

I've had 1 dyna module fail and 3 coils failed. One time I had a coil intermittently fail and the module for the other side fail. It took me awhile to 1. get home and 2. figure out what I had going on. The 3 coils I had fail  all worked intermittently and then failed whenever. The box just died on one side. That you had one side running momentarily says that the wiring to the ignition system was working.
It starting fluid doesn't start it send the coils and box back to Dyna and have them tested. I too will put points back on mine if I have another failure on Dyna. New non Dyna coils and points ignition.
This reminds me of what the late great Joe Eish said to me when I wanted to buy a dizzy for my Mille. He asked said what are you doing? I said Dyna and he said don't do it. He said the last time he had set his points was 75,000 miles ago. Joe continued they are bullet proof. RIP Joe.

[ozarquebus]

I called Dyna a while back for an intermittent problem with my Dyna equipped SPII and they did not offer a testing service or online assistance other than to tell me they do not fail intermittently.
I bought a full Dyna Kit just to eliminate ignition potential problem. That wasn't it, so now I am pursuing carb demon for the right side gas fouling.

[pete mcgee]

I have never had an issue with the dyna 3.
I have had 3 piranha electronic ignitions die on me, which is why the points plate and points live in the bag. Always on 100 deg days 100 + miles from home.
The dynas been in there 21 years and 130,000 miles.
But obviously YMMV.
Cheers

[redrider90]

I have never had an issue with the dyna 3.
I have had 3 piranha electronic ignitions die on me, which is why the points plate and points live in the bag. Always on 100 deg days 100 + miles from home.
The dynas been in there 21 years and 130,000 miles.
But obviously YMMV.
Cheers

There is always one Dyna lover who ruins any anti dyna thread I have read. 

[centauro]

There is always one Dyna lover who ruins any anti dyna thread I have read. 

I have also had bad luck with the Dyna III and their coils. My SP came with these from the previous owner.
Years ago, in slow traffic and on a hot day, the left Dyna coil cracked open and I had to limp home on one cylinder.

Even after changing both 3 Ohm coils to 5 Ohm ones, according to well known advice, I still had no spark on left side. I called Larry at Dynatek, who had me send the Dyna module to them. It turned out to be bad, and they offered to replace it at 1/2 price. I accepted that, and also found out that the "widely respected" NGK plug cap on the left side was also bad, as in no-continuity.
I came to the theory that a chain reaction had happened: the bad NGK cap had caused the coil to overheat and fail, followed by the left side of the Dyna module. Larry at Dynatek agreed with my assessment, and even suggested to change the caps to non-resistance ones.

Replaced both caps, and things were ok with the ignition for a few years. Eventually, even one of the 5 OHM coils became defective, with high resistance on the primary circuit. My final solution was to go back to 3 ohm coils and add a relay and new kill switch to the coils and Dyna circuit. And it remained that way until I sold the bike, not because of all of that, but because it had become too ponderous for me to handle with my back pain.

I am now convinced that the original points system is perfectly fine on these old Guzzis, and really most old bikes, as well. My '73  Honda CB 350F still has the points, runs great, and over my dead body it will ever replace it with a Dyna system which is available for this model, as well.

[bmc5733946]

I'm not a Dyna basher by any means but it seems, as I said earlier, that the smaller production units for smaller markets have issues. I had a Dyna ignition and coils on my Honda CB750F that worked very well for long miles and over many years. I do think that the Guzzi application, maybe because it's a twin, stresses their coils to some extent with long dwell times etc. maybe also stressing their ignition box as well. Electronics is weird stuff, maybe some electronics whiz could explain it to us. I know that collapsing magnetic fields can induce some pretty weird effects/affects where they travel.

Brian

[Testarossa]

Well, there was nothing wrong with the Dyna III, other than that it wasn't getting the amps it needed -- thanks for suggesting that, Centauro.

After spraying DeOxit onto all the switch terminals and into all the Molex connectors -- far too many of them! -- I still couldn't get a cylinder to fire. So I ran a jumper from the battery directly to the coils and bang. That was it.

I've been working without a wiring diagram for this bike from the beginning -- the harness doesn't correspond to any other Guzzi made in '89, which all had electronic ignitions (Motoplat I think). The closest points map I could find was Carl Allison's diagram for the '87 Cali III. That bike puts the coils in parallel with the rear brake light switch. On the Mille, that switch sits behind the coils. So I ran a jumper from the positive terminal of the brake light switch to the coil power terminals -- a four-inch run -- and now have a fused line to the ignition system. I don't know which fuse it is, of course -- no wiring diagram, and no labelling on the four fuses. But the bike runs great on the Dyna III now, so we're happy again.

[ozarquebus]

I have a question about the Dellorto PHF 30s which I think are the same as on the Mille as my SP2.
 
Is there a typical number of miles on the bike that the main diffuser tube that the main needle operates in, gets enlarged and runs rich? 42,000?

[bmc5733946]

So glad you got it fixed! The Cal III is the closest wiring diagram I have found as well, works for most things. Mine doesn't have a sidestand switch but has the relay for one, which I have repurposed, for what I can't remember. I use a Brother label maker and label anything that I identify on my travels through the wiring harness so I know I labeled that relay. Mark Twain said "An honest man doesn't need to remember anything." I say "A man with a label maker doesn't need to remember much." ain't I a smart guy?

Brian

[jwinwi]

Well, there was nothing wrong with the Dyna III, other than that it wasn't getting the amps it needed -- thanks for suggesting that, Charlie.

WOW, imagine that.   

[bmc5733946]

You know that weak amperage thing could be a lot of the failure problem for Dynas that I've seen. I never thought about the amperage just the ability to light a test lamp. Got voltage should work, maybe not. I wonder if the low amperage could even damage the Dyna coils or the unit itself, wouldn't think so but what do I know. A little knowledge can be useless tool. Guilty! Somebody apply Ohm's law for me, low amperage creating heat etc..

Brian

[Don G]

I mentioned in the fifth post that the power circuit to the Dyna should be checked, first things first....  DonG

[centauro]

Well, there was nothing wrong with the Dyna III, other than that it wasn't getting the amps it needed -- thanks for suggesting that, Centauro.

After spraying DeOxit onto all the switch terminals and into all the Molex connectors -- far too many of them! -- I still couldn't get a cylinder to fire. So I ran a jumper from the battery directly to the coils and bang. That was it.

I've been working without a wiring diagram for this bike from the beginning -- the harness doesn't correspond to any other Guzzi made in '89, which all had electronic ignitions (Motoplat I think). The closest points map I could find was Carl Allison's diagram for the '87 Cali III. That bike puts the coils in parallel with the rear brake light switch. On the Mille, that switch sits behind the coils. So I ran a jumper from the positive terminal of the brake light switch to the coil power terminals -- a four-inch run -- and now have a fused line to the ignition system. I don't know which fuse it is, of course -- no wiring diagram, and no labelling on the four fuses. But the bike runs great on the Dyna III now, so we're happy again.

The mod you did by tapping on the rear brake light switch via a short wire is undoubtly nifty and elegant, but you are adding an extra load on that circuit, and its applicable fuse may blow, leaving you stranded. BTW, to find out which fuse protects your new circuit, all you have to do is remove the fuses one at a time while the motor runs; the removed fuse that stops the motor is the one that protects the brake light and the ignition.
What I suggest is to add a dedicated relay powered directly by the battery positive via a 10 amp fuse. This separates the ignition from the rest of the electrical system, and would be easy to diagnose if the the ignition fails.