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Eldorado 850 running on one cyl

Terrorshark

Just got it firing!
Joined
Oct 9, 2018
Messages
6
Location
Denver
electronic ignition. Timing is good.
Has great compression.
Valves adjusted to spec.
Sparking in both sides.
Dellorto carbs recently put on.
New distributor springs.
Cleaned distributor.

Bike runs on the right cyl no problem.
At idle it won't fire on the left side but at higher rpm it will fire just pops a bit.

After distributor rebuild, it will only run on right side and doesn't want to get above 3-4K rpm.

Any ideas??
 
Recent carb change is my guess. If both sides spark, then it has to be fuel. Have you verified valve adjustment?
 
Left side plug is wet. Definitely running a little rich but nothing that shouldn't run. Valves are adjusted and in spec
 
I had that once on my Eldo. I had inadvertently reversed the points/coil/plug wiring.
Spark, fuel, etc on both sides.

Alex
 
Ooops that was on a dual point G5.
Yer electronic ign... is it possible to reverse the plugs?

Alex
 
Left side plug is wet. Definitely running a little rich but nothing that shouldn't run. Valves are adjusted and in spec

Are you still running the cap and rotor? If plug is wet and not running it suggests no spark, but you say you have spark on both sides.
 
You posted: "At idle it won't fire on the left side but at higher rpm it will fire just pops a bit".

By "not firing" do you mean no spark?
It would be odd to have no spark at idle but have spark at higher RPM.

Are you running a single coil & the old cap & rotor system or did the electronic ignition do away with that?
If single coil & cap/rotor system then a bad/cracked cap +/or bad plug wire would keep it from firing on that side.

If by "not firing" you mean that at low speed/idle the cylinder is not running but you do have spark then it would more than likely be a fuel issue.
If plug is wet then I would look at the choke/fuel enrichment circuit.

I would also replace that wet plug with a new one.
I have seen plugs that got wet & would fire outside the cylinder but when installed they would not work.

I used to have a machine that tested plugs under pressure, it used an air compressor to simulate compression.
It had a sight glass so you could observe the plug.
I used it to pick the best plugs for racing engines.
 
Little update on the bike.
New plugs.
New boots.
Spark on both sides.
Left cyl will not ignite at low rpm.
Above around 3-4K will start firing.
 
OK. You didn't answer/clarify some of the questions posted previously so lets try a different approach.

Go to parts store & buy a can of carb cleaner.

If you haven't done it already then pull the rubber boot that goes between carb & air filter box.
Start the bike.
Spray a short shot of carb cleaner into the throat of the left side carb.
Does the bike "fire" on the left cylinder now?

Do this & report results.
 
Can anyone tell me what degree I should be static timing on? I think the marks on this rotor are off
 
5 degrees before TDC. Timing marks are on the crankshaft pulley and timing case. It can be off depending on how the pulley was assembled when adjusting the generator belt tension. It can be wrong in two positions.
 
A little update.
Bike is timed using a degree wheel and timing at 5 degrees before tdc then static timed with a test light.
It will idle and run but still seems to be misfiring on the left side.
Opening the choke seems to help. i have pilot jets at #50
Mains at #125
Choke jet at #65
Right side seems to be running great but the left side sputters and pops unless the choke is on which of course ups the idle as well.

Again I have an electronic ignition.
Valves lash adjusted to spec.
Seems to be timed properly.
Great compression in both cylinders.
New plug boots
New plug wires
New coil
New plugs
 
I'm just going to post this again:
OK. You didn't answer/clarify some of the questions posted previously so lets try a different approach.
Questions not answered:
John Asked:
Are you still running the cap and rotor? If plug is wet and not running it suggests no spark, but you say you have spark on both sides.
Trout Asked: Are you running a single coil & the old cap & rotor system or did the electronic ignition do away with that?
If single coil & cap/rotor system then a bad/cracked cap +/or bad plug wire would keep it from firing on that side.

TRY THIS: If you haven't done it already then pull the rubber boot that goes between carb & air filter box.
Start the bike.
Spray a short shot of carb cleaner into the throat of the left side carb.
Does the bike "fire" on the left cylinder now?
Do this & report results.

Seriously, you have to determine if it is fuel or spark before fixing the issue.
 
Where are your idle mixture screws set at? If it runs on left w/choke on but not at idle w/choke off I would start by backing out the idle mixture screw 1/2 turn. That IS the circuit the gas goes through for idle. It's the little screw on the side of the carb.
 
Similar issue on Cali 2 turned out to be float on 1 carb was slightly high, causing over rich condition at idle but ran smooth off idle. Adjusted float minutely, now idles fine. Poor wire or gap will allow for weak spark at idle also. Make sure jets are clean it's usually something that simple.
 
Last edited:
Update.

After timing again with a degree wheel. Bike seems to be running great. Thank you so much for all your help
 
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