1 cylinder not firing

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I've searched the archives, and while I found similar, nothing seems to fit this situation-

Bike was running good. But did not seem to be running 100% on the right side. This bike has all new wiring last year, new coils last year, new battery, Pazon ignition, twin amal carbs. Changing plugs, ran good at idle, on road really missing, came home and cylinder not running at all, or if (I do get a puff of smoke occasionally) running very sporadically.

I've done this:

1) double checked timing with strobe- off a tad, now as close as I can get it.
2) replaced plugs, wires and caps with good copper core wires and NGK resistor caps, new NGK plugs
3) switched wires, plugs
4) took lead at plug, and switched to other plug leaving the coils the same

No change. Bikes starts 1st kick, but same problem. pulling right lead off plug while running- no change. Pull left while running, immediate kill.

I had compression, at least enough to run as a thumb pressed firmly over spark plug hole cannot be held in place with even a mild kick through,
and the gas the sprayed out, indicates it is getting gas.

A check of spark at the right lead, shows good spark.

things I haven't done yet:
1) I have not load tested battery- but have a bright light off, and running so should be enough.
2) Haven't checked valve settings, but no clatter and good compression , and since I set them early season, should be close enough to fire but will recheck as a next step
3) have not checked coils

I feel I can rule out gas, compression, and timing- which just leaves elec. Yet I'm getting a good spark. I do understand that a plug can spark good when not under pressure and fail when under load, but changing plugs did nothing. Can it be a coil- have 2 newish coils (under a year and 1000 miles)- thats breaking down under load? Yet, running the opposite coil to right side is no change.

I'm now at a loss. Any help appreciated.
 
"and the gas the sprayed out, indicates it is getting gas."

Gas sprayed out? Sounds like way too much fuel is going into the bad cylinder
 
the instructions for the pazon recommends the caps- wasn't running them, just regular caps with copper wires and autolites- changed the wires/caps yesterday and the new ngk plugs- And using the ngks recommended- also have new champions but don't think its the plug

if gas going into cylinder and its not firing, wouldn't there then be excess gas?
 
Take a look at the plug cap where it is screwed on to the HT lead. Sometimes worth cutting 1/2" off the cable and screwing the plug cap back onto the lead. And / or replace the plug cap.
 
"twin amal carbs."

To clarify, are those carbs new? Take the RH carb apart, inspect.
Swap sides with coils.
Report back.
 
the instructions for the pazon recommends the caps
Regardless you only need 5K ohms of resistance to protect a digital electronic ignition from HT interference, the instructions probably assume you have the original spec non resistor plugs as per the handbook and manual. As NGK plugs are now 100% 5K ohm resistance the cap does not need to be a resistance cap adding another 5k ohms. Resistors do fail leaving you with no spark so best to only have 2 not 4.
 
I've searched the archives, and while I found similar, nothing seems to fit this situation-

Bike was running good. But did not seem to be running 100% on the right side. This bike has all new wiring last year, new coils last year, new battery, Pazon ignition, twin amal carbs. Changing plugs, ran good at idle, on road really missing, came home and cylinder not running at all, or if (I do get a puff of smoke occasionally) running very sporadically.

I've done this:

1) double checked timing with strobe- off a tad, now as close as I can get it.
2) replaced plugs, wires and caps with good copper core wires and NGK resistor caps, new NGK plugs
3) switched wires, plugs
4) took lead at plug, and switched to other plug leaving the coils the same

No change. Bikes starts 1st kick, but same problem. pulling right lead off plug while running- no change. Pull left while running, immediate kill.

I had compression, at least enough to run as a thumb pressed firmly over spark plug hole cannot be held in place with even a mild kick through,
and the gas the sprayed out, indicates it is getting gas.

A check of spark at the right lead, shows good spark.

things I haven't done yet:
1) I have not load tested battery- but have a bright light off, and running so should be enough.
2) Haven't checked valve settings, but no clatter and good compression , and since I set them early season, should be close enough to fire but will recheck as a next step
3) have not checked coils

I feel I can rule out gas, compression, and timing- which just leaves elec. Yet I'm getting a good spark. I do understand that a plug can spark good when not under pressure and fail when under load, but changing plugs did nothing. Can it be a coil- have 2 newish coils (under a year and 1000 miles)- thats breaking down under load? Yet, running the opposite coil to right side is no change.

I'm now at a loss. Any help appreciated.
Having completed checks 1 thru 4 with no change doesn't leave much other than the right carb .. Personally , i would focus my attention there . Time to drop the carb .. Float issue ...main jet loose ..... needle ??
 
Having completed checks 1 thru 4 with no change doesn't leave much other than the right carb .. Personally , i would focus my attention there . Time to drop the carb .. Float issue ...main jet loose ..... needle ??
I think you are right. Am I correct in assuming that if I change leads to the plugs from the coils,with no change (left coil going to right plug, right coil to left plug) the both coils are good, and its not some funky magic stuff having 2 6 volt in series to 12? But then, again assuming, that if either coil was bad, switching would show that. Or would I have to switch the black/yellow etc ignition wires as well? Or doesn't that matter either way? I'd like to at least 99% eliminate and ignition/electric possibilities before taking off carb. Not that its that hard to do, more a PIA.
 
Am I correct in assuming that if I change leads to the plugs from the coils,with no change (left coil going to right plug, right coil to left plug) the both coils are good,

Just the leads assuming they will reach.

pulling right lead off plug while running-

It's usually not recommended to pull plug leads off when the engine is running as it can damage electronic ignition.
 
Check the needle in the side that isn’t running. I had the same problem once . When I put the slide back in the carb I unknowingly bumped the needle out of position causing overly rich condition.
 
Assuming you moved the plug end of the HT leads left for right etc., (such that the left coil now firing right side) then you can now rule out the coils and leads as the cause.

At this point I'd suspect fueling, likely way too rich (flooded) leading to no bang from that side. Float needle valve not sealing the bowl? Carb needle not held correctly in the little clip?
Also possible there is an air leak past the carb on that side, leading to overly weak mix and little to no bang. One way to help find leaks...with engine idling, hold a propane torch nearby with a rubber hose of the end...open the torch and position hose right up along each carb to manifold and manifod to head sealing surface. Any idle change indicates air/propane entering at that point.
 
Assuming you moved the plug end of the HT leads left for right etc., (such that the left coil now firing right side) then you can now rule out the coils and leads as the cause.

At this point I'd suspect fueling, likely way too rich (flooded) leading to no bang from that side. Float needle valve not sealing the bowl? Carb needle not held correctly in the little clip?
Also possible there is an air leak past the carb on that side, leading to overly weak mix and little to no bang. One way to help find leaks...with engine idling, hold a propane torch nearby with a rubber hose of the end...open the torch and position hose right up along each carb to manifold and manifod to head sealing surface. Any idle change indicates air/propane entering at that point.

"Assuming you moved the plug end of the HT leads left for right etc., (such that the left coil now firing right side) then you can now rule out the coils and leads as the cause."

yes, so ruled out.

not an air leak- but I do think that it might be as you and Richard have suggested. Everything else has been eliminated. It has been fouling plugs on that side. I'll try to find time to pull the carb in next day or two- busy with work and time in short supply. But I'll report back my findings for sure.
 
won't know till get a chance to look- hopefully later today- but if not it won't be for a few days.

Plug looks like a new plug, since it isn't firing.

Carbs not new, but were thoroughly cleaned and inspected late last summer, and the bike put on 700 or so miles before winter. The bike seemed fine then. BUT- when I put the turn signals back on, or actually the tank, we bound the throttle cable so when turned, stayed so perhaps that did something- when we took the tank off and redid the cable, it seemed fine, and have put on 2 good rides of 250 or so miles each, and no concerns. But the next ride we didn't get out of town because of the missing/non firing- thats when I retimed and did new plugs and wires. But maybe that was the source, and yes, I won't know til I look.

Be nice if when I do take it off, its something obvious where I say ahh- thats the problem.
 
won't know till get a chance to look- hopefully later today- but if not it won't be for a few days.

Plug looks like a new plug, since it isn't firing.

Carbs not new, but were thoroughly cleaned and inspected late last summer, and the bike put on 700 or so miles before winter. The bike seemed fine then. BUT- when I put the turn signals back on, or actually the tank, we bound the throttle cable so when turned, stayed so perhaps that did something- when we took the tank off and redid the cable, it seemed fine, and have put on 2 good rides of 250 or so miles each, and no concerns. But the next ride we didn't get out of town because of the missing/non firing- thats when I retimed and did new plugs and wires. But maybe that was the source, and yes, I won't know til I look.

Be nice if when I do take it off, its something obvious where I say ahh- thats the problem.
The plot thickens...
 
took the RH carb off. disassembled and recleaned everything, although it looked very clean. Took out slide, double checked smothness and checked for any abnormalities & found none.

Needle secure in middle notch. Jet tight.

Did seem to be excess amount of gas at air cleaner throat when removing.

Only thing it might be, and I stress might because not sure if it was or not- was the possibility of the clip being caught in the spring. But if it was, I could see that causing the flooding conditions, in any case, operating normal now.

Nothing jumped out- float, float needle etc are ok (and new last year)...and if it was float, etc- then wouldn't it constant drip out of tickler? In any case, no float leaks and nothing out of place.

got carb back on bike, but need to get some stuff done- hopefully can get it buttoned up and fired up tonight yet.

Any thoughts?
 
took the RH carb off. disassembled and recleaned everything, although it looked very clean. Took out slide, double checked smothness and checked for any abnormalities & found none.

Needle secure in middle notch. Jet tight.

Did seem to be excess amount of gas at air cleaner throat when removing.

Only thing it might be, and I stress might because not sure if it was or not- was the possibility of the clip being caught in the spring. But if it was, I could see that causing the flooding conditions, in any case, operating normal now.

Nothing jumped out- float, float needle etc are ok (and new last year)...and if it was float, etc- then wouldn't it constant drip out of tickler? In any case, no float leaks and nothing out of place.

got carb back on bike, but need to get some stuff done- hopefully can get it buttoned up and fired up tonight yet.

Any thoughts?
Did you verify flow through EVERY passage using aerosol solvent, like brake cleaner?
Did you verify choke slides do what they supposed to?

Next, take an extra spark plug, put the RH lead on it, lay it on the cylinder head. Start the engine (on the left cyl) rev it, watch for spark. Easy 2 minute test. Report back.
 
I had a similar problem ..... not firing on right cylinder.
Problem due to excessively rich mixture. After disassembly of carb for third time, I noticed the jet block gasket seemed worn. New gaskets both sides solved the problem. This was with Monobloc carb. I diagnosed a similar problem with concentric carb that turned out to be a loose pilot jet.
Good luck with it.

Slick
 
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A remote possibility but a quick and easy one to check is the engine earth. If this is compromised but still just about connected then you only get enough current for only one spark and it always seems to favour one side. Connect a wire directly from the head to the battery earth terminal and see if the right side chimes in.
 
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