72 Eldo wont run anymore

[DodgeBoy]

Hey everyone,

I am a little bit desperate right now and looking for some input regarding a problem with my 1972 Eldorado 850. Sorry for the long text in advance.

When I bought the machine last spring it ran quite well through the season but it had some work to be done to it which I allready know when I bought it. So what else to do during the cold winter days than working on an old bike, right?

It was a completely stock setup but with a very tinkered wiring harness. What has been done for now:
- heads refurbished by HMB-Guzzi with new seats for unleaded fuel, new exhaust manifold nuts
- completely new harness by Greg Bender
- new electrics (new Marelli-coil, new Bosch electronic voltage regulator (9 190 040 099 E), new NGK BP6ES spark plugs, new spark plug wires with 5kΩ boots
- new distributor cap, new condenser, new points, new rotor (note I have never removed the distributor itself but i cleaned it from inside)
- new petcocks + fuel lines
- new oil breather box
- carbs (Del'Orto VHB-29) were professionally ultrasonic cleaned, new needles, new jets but everything stock sizes.

After we had done all that I once checked compression before firing the Guzzi up the first time (cold both zylinders 10,5 bar/152 psi). Checked valve clearance and gaps as well.
When we finished everything up it was late in the evening but we gave it a try. The Guzzi fired up without any problems, was very responsive and I was happy. We let it idle (very steady) for about 5-10 minutes and called it a day.

The next day I wanted to take the machine out for a short spin in the city to warm it up. Plan was to synchronize the carbs after that and then retorque the heads after another ride but thats were the problems started...

First the Eldo did not start as well as the evening before but it ran - maybe a bit rougher but okayish. After it warmed up it startet to rev up while idling so i thought its the mixture. I went home after about 15 minutes on the street. After that the machine had very hard times to start again until it wont start anyways. We tinkered around, recharged the battery (old one) and managed to get it back starting. From then on until now I was not abled to bring the bike back on the street by no means.
It runs super rough and unstable on both cylinders. When I disconnect one cylinder it will run between 500-800 rpm, sometimes with ignition fails. With both cylinders running as soon as I touch the gas I will immediatly die or nearly stall. It will react very different on the choke.

Sometimes it wont run with choke, sometimes it only runs with half open choke.

I allready tried to get in touch with two local Guzzi shops but they refused..
The carbs have been sonic cleaned a second time now but still same problem.




There are a few things that causing me headaches:

- First I was so dumb and changed the mixture screws on the carbs and threw the old/factory one in the bin (the heads were very worn). Now I have the ones installed that for example MG Cycle sells but they have slightly shorter tips at the end. The german guys told me not to wonder it wont work with these mixture screws because they dont have the same shape as the factory ones in general. BUT:
a) the bike ran perfectly with these for 10 minutes at least.
b) MG Cycle told me these aftermarket mixture screws are used on VHB-29 without problems from their knowledge.
c) Guzzitech users told me that this style srews were basically used by the US-modells from factory at a certain point but I dont know if thats true.
Anyway I am still annoyed about myself for binning the old srews so I cant swap back to check and there is no way to find these old ones without buying a complete carb.

___________________ ___________________ ___________________ ___________________ ___

When I cleaned the distributor out I checked the two tiny advance (return) springs and the shorter one looks a bit loose. I dont know if that can cause any missbehavior like that on static idle?

___________________ ___________________ ___________________ ___________________ ___

The new oil breather is an aftermarked one from Stein-Dinse. What symptoms would accure if that oil breather would be faulty/clogged?

___________________ ___________________ ___________________ ___________________ ___

I bought 2 new distributor rotors. One did not fit correctly and caused the dist. cap to move while rotating. The now installed one looks similar to the factory one but I am not sure if a slightly different upper contact could cause that? But again, the Guzzi ran well for a short time.

___________________ ___________________ ___________________ ___________________ ___

The wire on the new condenser ist very thin. Which behavior would a faulty condenser result in?





Any thoughts would be highly appreciated.

[Don G]

A faulty condenser will result in a weak spark. Check the spark at the plugs, does it have a robust blue spark? Or is it orangish? Keep in mind although the spark seems ok it will be different under compression with a rich fuel mixture. I would inspect the condition of the ignition components first, also check voltage to the coil, also check the spark leads and resistor caps with an ohm meter to see if they are in range. These are simple machines with simple problems, if everything is in correct operating parameters we would not be having this conversation. So go back to basics verify compression, valve clearance, spark delivery, correct voltage etc.  DonG

[Antietam Classic Cycle]

There are a few things that causing me headaches:

- First I was so dumb and changed the mixture screws on the carbs and threw the old/factory one in the bin (the heads were very worn). Now I have the ones installed that for example MG Cycle sells but they have slightly shorter tips at the end. The german guys told me not to wonder it wont work with these mixture screws because they dont have the same shape as the factory ones in general. BUT:
a) the bike ran perfectly with these for 10 minutes at least.
b) MG Cycle told me these aftermarket mixture screws are used on VHB-29 without problems from their knowledge.
c) Guzzitech users told me that this style srews were basically used by the US-modells from factory at a certain point but I dont know if thats true.
Anyway I am still annoyed about myself for binning the old srews so I cant swap back to check and there is no way to find these old ones without buying a complete carb.

___________________ ___________________ ___________________ ___________________ ___

When I cleaned the distributor out I checked the two tiny advance (return) springs and the shorter one looks a bit loose. I dont know if that can cause any missbehavior like that on static idle?

___________________ ___________________ ___________________ ___________________ ___

The new oil breather is an aftermarked one from Stein-Dinse. What symptoms would accure if that oil breather would be faulty/clogged?

___________________ ___________________ ___________________ ___________________ ___

I bought 2 new distributor rotors. One did not fit correctly and caused the dist. cap to move while rotating. The now installed one looks similar to the factory one but I am not sure if a slightly different upper contact could cause that? But again, the Guzzi ran well for a short time.

___________________ ___________________ ___________________ ___________________ ___

The wire on the new condenser ist very thin. Which behavior would a faulty condenser result in?





Any thoughts would be highly appreciated.

As I have written several times, the short tipped mixture screws are what came in VHBs. Anyway, they would not contribute to a "no start" issue.

One advance spring will fit a bit loose, that's the way it's designed. Wouldn't effect starting.

The oil breather would make no difference either.

Quality of the commonly available rotors and caps is poor. Perhaps the improperly fitting rotor damaged the cap. If you have the original rotor and cap, try those.

Try a different condenser - the original if you have it.

Try different plugs (a brand other than NGK). My V50 III would only start and run on one cylinder with brand-new, properly gapped, NGK plugs. Installed Denso plugs and it started and ran perfectly.

[Vecchio Lupo]

great advice so far. The only thing I might add is double check the points, they may have closed up a bit in the initial run and completely on the second. Please keep us posted.

FWIW: this smells like timing/ignition , many times electrical issues feel fuel related at first.

[Canuck750]

A faulty condenser will result in a weak spark. Check the spark at the plugs, does it have a robust blue spark? Or is it orangish? Keep in mind although the spark seems ok it will be different under compression with a rich fuel mixture. I would inspect the condition of the ignition components first, also check voltage to the coil, also check the spark leads and resistor caps with an ohm meter to see if they are in range. These are simple machines with simple problems, if everything is in correct operating parameters we would not be having this conversation. So go back to basics verify compression, valve clearance, spark delivery, correct voltage etc.  DonG

What Don said!

Last year at a vintage rally my 72 Eldorado ran very rough, no power, could not get up to 50 km/hr right after filling up. I thought it was bad fuel but after a lot of fiddling in the campground (Don was there) it turned out to be a bad condenser and poor fitting high tension leads into the distributor cap, the brass ends on the high tension leads were not seating all the way into the distributor cap, arcing was visible outside the cap as daylight faded.

The consensus is the arcing caused the condenser to fail, I fitted proper brass tips onto the high tension leads, got the high tension leads to fit all the way into the cap and installed a new condenser. The Eldorado ran great thereafter.

[moto-uno]

   The only thing that has ever left my custom Guzzi (with single point distributor) stranded was a condenser that made it very
hard to start and within 2 kilometers it stopped dead and required a tow . New condenser, started instantly and has run great for years .
The only part of a points ignition I hold in contempt . (Guess what's in the saddlebag :) ). Peter

[DodgeBoy]

Thank you all at first for your help!

yesterday I ordered a new condenser and some different spark plugs (Bosch W6DC) just to try them out. I think I will order another, different condenser today just in case and keep my fingers crossed.
If that new consender which is installed right now turns out to be faulty allready I have to think about packing a hand full of those in the bike Seems they are very delicate...

"...also check voltage to the coil... to see if they are in range..."

Yes, thats another thing I had in mind. It would be a bummer if the brand new coil is allready shot. We allready measured through if its shortened but it seems not to be. Otherwhise the bike would not start at all if the coil is shot right?

As I have written several times, the short tipped mixture screws are what came in VHBs. Anyway, they would not contribute to a "no start" issue.
One advance spring will fit a bit loose, that's the way it's designed. Wouldn't effect starting.

Of course I remember we talked about the issue with the mixture screw but it still was a thing in my head. Mainly because the German community is a bit...lets say overcautiously with that and I am still a rookie with that topic.
I see how the springs should work no and the loose one engages later - thanks 

[Dukedesmo]

Whilst I had no issues with them, I did away with the condensers on my LM2.


I fitted a Gammatronix Electronic ignition module. It leaves the points in place but reduces the load on them so they don't deteriorate so quickly due to arcing, gives a stronger spark too.


Seems to work very well and not expensive or complicated to fit and they have a nice LED so you can see when they're firing to help when setting static timing. 


Info here; https://gammatronixltd.com/epages/bae94c71-c5b6-4572-89a1-e89006e78fbe.sf/en_GB/?ObjectPath=/Shops/bae94c71-c5b6-4572-89a1-e89006e78fbe/Products/NewTwinC-12VNEG

[jacksonracingcomau]

Hey everyone,

I am a little bit desperate right now and looking for some input regarding a problem with my 1972 Eldorado 850. Sorry for the long text in advance.


The next day I wanted to take the machine out for a short spin in the city to warm it up. Plan was to synchronize the carbs after that and then retorque the heads after another ride but thats were the problems started...

First the Eldo did not start as well as the evening before but it ran - maybe a bit rougher but okayish.

a) the bike ran perfectly with these for 10 minutes at least.
b




Any thoughts would be highly appreciated.

Plan was good, go ahead with it, retorque and set clearances, report back

Of course any of your new components MIGHT have decided to stop after one heat cycle but sure as eggs are eggs your head gaskets have settled .
Do it again after 500 miles and clearances should stay good for ever

Re condensors — the originals almost never failed, modern repros can last seconds— refit the original
Same with button and cap, if not physically worn/ broken use Marelli gen (original parts)
My 67 V700 has all original electrical bits and I’ll bet they outlive me

[tris]

.......
I bought 2 new distributor rotors. One did not fit correctly and caused the dist. cap to move while rotating. The now installed one looks similar to the factory one but I am not sure if a slightly different upper contact could cause that? But again, the Guzzi ran well for a short time.
......

This might be important. Did it stress the cap and after the heat cycle caused a crack or something similar

[DodgeBoy]

This might be important. Did it stress the cap and after the heat cycle caused a crack or something similar

Hmmm I don't think so... both caps look fine I would say but as soon as the spare parts arrive I will try interchanging the parts - both caps as well.

[Tkelly]

I once had a t3 with very high miles whe I bought it.The points would get out of adjustment afeter a few hundred miles .I think the problem was that the bearings for the distributor were worn.The bike may have ha a couple hundred thousand miles on it.

[DodgeBoy]

Guys!
I am feeling so stupid and grateful the same moment right now!
Honestly I was close putting the Eldo on the wall and forget about it for this season, i was so full of it.
Whilst nearly everyone in the german forums blamed me for tinkering with the carbs and two Guzzi shops denied my help request you guys just came with the solution within one day..

I came home from work today and spotted that old Marelli condenser in the box and thought f* it i wont wait for the other parts but throw that old ratty condenser in right now.

The old bitchy lady responded instantly! Mixture still way too rich but i dont care right now. 
Thanks so much all of you. It seems the brand new condenser died right after the very first ride!!!! Not instantly but start after start.
Some german guys told me before that a faulty condenser wont cause that issues but a too hot spark that will burn the points after hours...and the contacts were clean the whole time!

Its time for a beer now. Tomorrow i will synchronize the carbs and see what the weekend brings.

 

[Chuck in Indiana]

 

[Tom]

  On solving the problem.  Doing the carbs is easy.  Good luck!  Zum Wohl!

[normzone]

I have a policy of not throwing out parts I have replaced unless they are demonstrably broken. I've had similar condenser experiences, including a car that would not start, so I put an old Guzzi condenser on it and it fired right up.

[DodgeBoy]

I have a policy of not throwing out parts I have replaced unless they are demonstrably broken. I've had similar condenser experiences, including a car that would not start, so I put an old Guzzi condenser on it and it fired right up.

So these old Marelli condensers will fix everything 

[Don G]

Enjoy!   DonG

[Canuck750]

 

[tris]

I have a policy of not throwing out parts I have replaced unless they are demonstrably broken.......

My Dad had that policy and now I'm in the middle of clearing the house, garage & workshop after his passing I'm finding all the knackered but "useful" stuff

To paraphrase the Jaws movie - "We're going to need a bigger skip" 

Well done DB for sorting it out though

[DodgeBoy]

Well....guys I think my Eldo is cursed or its me.
After it ran now with the old capacitor I did the timing, mixture, idle 1200 rpm and synchronized the carbs yesterday - went like a breeze. I then took the bike out for an evening city stroll - about 4 miles, between 18-31 mph mixed.

At first the bike ran well, maybe a bit lean on acceleration.
Exactly half of the way on the turning point red light came on - oil pressure. Okay I thought thats new for me on that machine as well. I stopped about 2 minutes later for a check and the new! (Stein-Dinse) oil breather spitted out a decent amount fresh engine oil while parking the Guzzi! The rear tire flanks are covered in oil as well yikes.

Immediately headed back whilst the machine started hesistating more and more on acceleration but not stalling. On the last mile I could hear a rumbling or bobbing starting and getting louder seemingly coming from the gearbox area or breather, not exactly sure right now.
Engine pressure red all the way.

When i tracked the way back i saw the breather lost a bigger oil drop every 5 meters and puked a hand full again when i turned the machine off in the drive way.

I am afraid to ask if it could simply be a faulty breather causing the noise or if its something inside the engine/trans now.

 

[czakky82]

How long did you ride with the oil pressure light on?

Did you check your oil level?

[DodgeBoy]

How long did you ride with the oil pressure light on?

Did you check your oil level?

I went straight home when it came on. About 10 Minuten on low city speed.
I changed the oil end last season and you can tell its freh unburnt oil spitting.

[JBU]

How much oil did you put in?  Do not rely on the dipstick.  Put in 3 Liters of oil, then you can mark your dipstick.

[DodgeBoy]

How much oil did you put in?  Do not rely on the dipstick.  Put in 3 Liters of oil, then you can mark your dipstick.

Yes, that was one of the first issues, that i was told that 2.5 liters 2.6 quarts?) would be enough... Hmm

[czakky82]

Does the motorcycle currently have oil on the dipstick?

That would be the first thing I would look at if I had an oil pressure light….

[DodgeBoy]

I checked the oil level today and it was bone dry. It seems i completely lost all the oil during the short test drive.

I removed the oil pan and yes there was nearly nothing left. Luckily there was absolutely no metal in the oil pan.

I refilled the engine with 2.5 liters of the same oil i was using during last season - Motul 20W-50 mineral classic oil - which ist enough for exactly half of the dip stick.

Drove the same tour as the day before but stopping and checking the oil breather athmosphere hose every 3-5 minutes. At first everything was fine but after about 10 minutes the breather started pumping out the oil. Literally pumping like you cut an artery. Huge squirts every 2 seconds repeatedly.
Headed home instantly using the side roads and when i came home I nearly lost 1.5 liters fresh oil!!!!!

Its a new breather from Stein-Dinse
https://www.stein-dinse.com/en/moto-guzzi-oil-condenser-v7-700-spezial-850-gt/item-2-1050679-12155701_.Z.html
The old breather worked fine with that oil.
Is that now the second faulty SD part within days or ist the 20W-50 too thin for that after market breather?? Could it bei that it sucks my whole engine dry even in idle with 1200 rpm!?

[czakky82]

It’s not the oil.

I’m not super familiar with loop breathers. Something is not right. Even with the flap wide open I don’t think it would pump oil that fast. But I don’t know.

[Tom H]

Are you sure that the oil is coming from the breather box outlet hose and not from the seam between the engine and the trans?

Hard to figure out how that much oil is coming out of the breather??

Tom

[normzone]

Well....guys I think my Eldo is cursed or its me.

No, it's not you. I've seen this before - It's a curse.

If you sacrifice a chicken to Nigoth The Worm God sometimes that will help. Roasted or fried, it's all good.

Oh, and listen to whatever these guys tell you.