Help with 850 Eldorado

[bassa99]

I have 1974 Eldorado that has been giving me ignition problems I believe. I bought the bike and had engine restored due to chrome flaking cylinders.  I checked timing both static and advance with timing light, all checked out properly and bike ran fine for awhile. It then started to run rough and die, some backfiring would occur before it would die. I have since replaced coil, condenser and points. It ran fine for about 50 miles and problem returned. The curious thing for me is that when engine was rebuilt by shop the distributor was not in same position relative to where it was for the first 50k miles of its life. The distributor is set with the arc with bolt to tighten to the left of arc where it had been more to the right judging from mark where bolt had been previous to rebuild. I wonder if distributor was set back off one tooth if possible. Hope this is clear as to what I suspect problem to be. I only sent engine to shop for rebuild and did the work to install engine in bike myself so shop did not run engine.

Thanks in advance

Allan

[Antietam Classic Cycle]

One tooth off won't hurt a thing as long as there is still "arc" available for timing adjustment.

Since the engine is a fresh rebuild, have you retorqued the heads? The head and base gaskets "sack", valve clearances close up and this could cause the symptoms you report. In the first 500 miles with a freshly rebuild engine, I retorque four times (at least).

Make sure the gas cap is venting properly as well.

[rodekyll]

One tooth is about 30*.  So it's possible to be a tooth out and still rotate the dizzy to time it.  If the static timing is correct this isn't your problem.

If the engine was gotten into, were the timing gears removed?  I saw a case a few years back where the eldo would go for a while and mysteriously die.  We rebuilt the distributor, tweaked the points plate, changed filters and coils and about everything else we could think of to no effect whatsoever.  The owner finally tore into the engine and discovered the cam gear nut was missing.  It had run perfectly for years without it until one day it didn't.

[bassa99]

Heads have been retorqued, valves set once since rebuild. Gas cap vent is clear also have opened cap when problem presents. Work was done in respectable Guzzi shop with longtime mechanic doing work.

[John A]

Does the distributor rotor spin when you spin the engine with the starter?

[Idontwantapickle]

Unplug the tach. See if it runs better.
Also check the ignition switch and wiring.

Hunter

[Markcarovilli]

Coil kill switch could be flaking out on you....

Mark

[Idontwantapickle]

Coil kill switch could be flaking out on you....

Mark

Yes, on a police model that could be.

[John A]

Unplug the tach. See if it runs better.
Also check the ignition switch and wiring.

Hunter

That's right the electronic tach on those can cause ignition problems. Don't remember exactly why

[craigclu]

I had some flaky behavior like this on a '73 Eldo after a tune-up and new points/plugs/wires/cap, etc.  Tore my hair out and in desperation, finally put the original distributor cap back on and everything magically worked.  I could not see a thing wrong with the new cap, even measuring all the dimensions.  It was the last thing I would have suspected....

[bassa99]

The bike is a civilian police model so no tach, I to have been tearing my hair out looking for old rotor and distributor cap. I will take a look at coil kill switch and key switch.

[Tom H]

The already mentioned are good places to start. But... have you checked the carbs for blockages? Especially the filters at the fuel inlets? When the problem happens, can you let it sit for a few minutes and then all is well for another few miles? Could be the filters? Also you might check the filters on the fuel valves and the valves themselves. Not all bikes had the filters I think.

Also, a new coil can be bad. I have had coils that don't want to work when hot. Fine at first start, but after getting heated up, stop working right.

Good luck,
Tom

[bassa99]

fuel system has been gone thru. Carbs rebuilt, petcocks out of tank to check for blockage. I am going to retorque heads again to see if I get it to run properly. Next step will be GULP open my wallet and let a pro have a go. Need to get this up and running as it is the most fun I can have with my clothes on.

[John A]

You could remove the wire and run a jumper to the coil + from the battery and bypass the rest of the harness for troubleshooting. I wonder if you have a pinched wire someplace .

[tetarabra]

Smells like rotten condenser 

You tested another one .
 Was it the same ? Coming from the same place ?
Nothing wroten on them ?

For information ,we faced a batch of very unreliable condensers , sometimes not working from new .

[normzone]

Smells like rotten condenser 

You tested another one .
 Was it the same ? Coming from the same place ?
Nothing wroten on them ?

For information ,we faced a batch of very unreliable condensers , sometimes not working from new .

You beat me to it - I've had some very strange problems occur but disappear when I dropped in a new condenser.

[smdl]

You beat me to it - I've had some very strange problems occur but disappear when I dropped in a new condenser.

Agreed, and a number of people have seen failures in new condensers.  If you have the old one still, put it back in and see what happens.

Cheers,
Shaun