Topic: 2 & 3 cylinders cold

[KrombopulosRyan]

I've been having issues with my newly purchased 76 CB550. It has a MotoGP Werks 4-1 exhaust, and came with pod filters, it would run but would stumble pretty bad above 5k rpm. Every once in a while it would bog out and die unless i was giving it a little gas, that to me said it I've got a carb issue.

I managed a carb rebuild this weekend and discovered that the carbs were still jetted for a 550K instead of a 550F and the float heights were set 4-5mm too low. With the new jetting the bike ran like a dream for the first day, no problems starting or idling, pulled all the way up to 80 no problem on the highway.

Problem is, today I go to start it and it sounds like it's bogging out again. I can get it to idle pretty steadily at 1K but it doesn't sound right. I touch the exhaust at the headers and find my #2 & 3 cylinders are cold. I was on my way to work so I couldn't do much beyond look at the spark plugs and they looked good, slightly tan, potentially a hair lean. Had to just take the girlfriend's car and get my ass to work.

The bogging "condition" has only happened a handful of times since getting the bike, and when it did it seemed to happen when the bike had been running a little while; and would return to normal after turning it off and giving it some time to cool down. This time the bike was cold.

I tested the ignition coils last week and I saw all the resistances I was supposed too, hence why I focused my attention on the carbs.

I take it I'm going to have to verify whether or not I have spark on those cylinders?

[Deltarider]

Yep. Plugs 2 & 3 are in a difficult spot, so careful. Best to use is the plugwrench that came with the bike. Have a look at the plugs noses. You can then connect them again to their caps, ly them against the engine and see if they spark when engine is cranked. Please report back.

[Jerry Rxman Griffin aka MuthaF'er]

Assuming you have points it could be the points or condensor for 2 & 3. Wiring/connectors? Swap coils around. 

[TwoTired]

Are your spark plugs sooting up?  Look at the spark plug deposits on the electrode insulators.

The stock F carb set up is for the stock High pressure exhaust.  Aftermarket exhaust usually have much less restriction and generally work better with the K set up settings.

However, there are some that drill the jets instead of getting new ones in the correct orifice diameter.  Check for that.
Also the needle taper profile is different for the F carb set ups.
Aftermarket carb kits sometimes have brass parts that don't conform to Honda dimensions.  If you have he carbs apart, try to determine if you have Keihin part installed in the carbs.


The float bowl fuel height is rather important.  Again aftermarket parts can change this, even though they are mechanically measured proper.  The little spring pin stiffness differences make the actual fuel height change.   So, use the clear tube method to know for sure what fuel level you actually have.

Done a carb vacuum sync yet?

Finally, it's rather silly to fine adjust carbs if the routine 3000 miles tune up checklist isn't completed first.

Cheers,

[KrombopulosRyan]

I plan on checking for spark on the # 2 & 3 cylinders after work, I only took one picture of the #2 cylinder's spark plug after I pulled it.

I did quite of bit of googling and asking around about the exhaust setup I have and it appears that going from a 100 stock main jet to 105 is all that usually needs to be done. The rest of the bike is completely stock, the frame even has all of it's tabs!

I'm basically just standing on the shoulders of enthusiasts that have come before me here in Southern California and copied the jetting of members (that TwoTired helped) from years passed I found on an old thread. I did verify the rebuild kit I ordered has the Keihin stamp versus the Mikuni stamp on them.

I know the jetting is closer to correct because the plugs went from bone white, to having a slight tan to them.

I did vacuum sync the carbs, the first time I was close but when I would let off the throttle the rpms would gradually fall back down to idle during my first test ride. After syncing again, and really dialing them in best I could, the bike rode like a dream (for a day).

When I first got the bike (2 months ago), I checked the following:

Compression,
Valve clearances,
Timing,
Ignition cables,
Coils

I'll report back in a few hours after I've tested for spark.

[KrombopulosRyan]

Got home, had to push it about a mile home, and I got the spark plugs out, capped, and ready for a spark test.

Then I right before I hit the start button something tells me to check the battery voltage before I do.

Measures 12.56V which is just below the 12.6V minimum for Yuasa batteries. Thinking I would see weak or no spark on # 2 & 3, I push the start button and see strong blue spark on each plug. That makes me wonder, what if i put the plugs back in and crank the motor? It started right up and idled like a clock at 1k... This problem has been intermittent so this isn't actually surprising that it worked.

What about the battery, could this be causing my problem? The starter turns over I didn't need to jump it this morning.

Any ideas?

[KrombopulosRyan]

Okay so after updating with that last post I went outside for a test ride and it happened as I started it again. Only firing on two cylinders, got the jumper cables out and tried it again.

Presto! Firing on all cylinders, I'm leaning towards faulty battery at the moment.

That makes me wonder what changed the condition of the battery and drained it? The bike has gotten daily use for 2 months with the bogging out condition only happening a handful of times while riding on the highway, never while starting the bike. Should I be chasing a leak, or looking at my charging system? The battery doesn't look too old, but how old it is, is anybody's guess.

Just would prefer to do some more testing and verifying before I go throwing money at the problem.

[scottly]

Just would prefer to do some more testing and verifying before I go throwing money at the problem.

Yes, you do need to do some more testing; 12.56V at rest is not necessarily an indication of a bad battery. First thing I would do is remove the points cover and see what's hiding there. Your intermittent symptoms sound like a common occurrence with a certain electronic ignition.    

[KrombopulosRyan]

Stock points and condenser setup.

I did notice that the gasket at the bottom of the points cover was spent, there wasn't any dirt or gunk on the anything under the cover. Needs replacing though.

[BobR]

No expert but I doubt its a battery issue. Does 2 and 3 share the same coil and/or points? If so it could narrow down the search. (FWIW I was looking at the info on this bike we have on this site shows electronic ignition?) ...I'd be looking at anything that might be loose/poor connection or possibly a bad coil , loose points, if its shared with 2 and 3.

[KrombopulosRyan]

Cylinders 2 & 3 share the left coil. I was actually thinking I'd let the bike sit and see if I can get the problem to happen again so I can tap the condenser that goes to the left coil.

Wait?..

Can't I test this stuff? Google just produced the attached .pdf for me, it says 750, but does the information still apply?

[scottly]

You have Diachi points, and probably condensers as well. Look at the bottom of the condensers for a three bladed propeller logo like on the points. These are known to be problematic.

[BobR]

Cylinders 2 & 3 share the left coil. I was actually thinking I'd let the bike sit and see if I can get the problem to happen again so I can tap the condenser that goes to the left coil.

Wait?..

Can't I test this stuff? Google just produced the attached .pdf for me, it says 750, but does the information still apply?

 Not sure on the values but you can compare the 2/3 values to the 1/4 coil values. I found this bit to be of interest.

"One other thing to remember is that the coils do get hot with use. It is possible for a coil to test good, but once it gets hot, the insulation inside starts to get gooey and breakdown. If it starts to misfire after it is hot, let it warm up until it happens and check the coil while it is hot. This can be tricky because it still needs to be disconnected first."

[scottly]

If your condensers have this logo, they are the most likely suspect.

[KrombopulosRyan]

Scottly you were right, Daiichi.

Any recommendations on where I should get a replacement from?

From what I've read taking ohm readings on those are pretty useless. Condensers are cheap, and if they are a known sub quality brand I'd rather get something good in there.

[Deltarider]

Diagnosis can't be made by just blaiming a brand. Some people have no problems with Daiichi. You could look for possible arcing at the points. At the breakerpoints a tiny bit of sparking is normal, excessive sparking is not good and indicates a bad condenser. See

Left condensor (1+4) is bad, right condensor (2+3) is good.
Another thing to be aware of is that the forked connectors at the back of the breakerpoints are not intermittently (because of vibrations) grounding. When installing make sure these forked connectors do not touch the baseplate (especially 2+3 can touch easily!).

[Deltarider]

See reply #5... Stop wasting time looking for a problem that exists in the most likely place 

2/3 cylinder are on the same coil, fed by the same points, and the same condenser. Its not a battery issue, its an ignition issue. Points and condensers, changed, done, ride on!

Could you be a more specific than replace just all? Not everybody here is addicted to buying stuff and opening parcels. Narrowing the diagnosis step by step, that's a real investment. And we all learn in the process.

[jlh3rd]

Oswald, I’m just curious..do you use the electric start and does it turn the bike over normally?...and is the bike charging as it should....you questioned your battery condition and rightfully so.....I’d just make sure the battery and charging system is working ,then I’d hit the other components.
     The 70’s Honda’s I owned back in the day and the one I have now do not like weak batteries.....

[PeWe]

Daichii points works but has not as good contact surface when closed as TEC. (Usually)
Not meeting each other exactly. Daichii I have had are often like bent, not using the entire contact surface. Trickier to adjust since the timing will change when tighten the screws holding them due to its body, not really flat.

Sure that the wire for 2-3 is connected all the way?
It might be the connection between point wire and main harness. That has been the case on my bike many times, a 2 problem I always have fixed really quick. First place I should  check. Next if 2-3 coil has 12V to it.
Wire must be correct connected on point plate too where the fiber washers are. Compare with working 1-4.

[evinrude7]

file and clean points.  then gap them correctly.  i'm also thinking condensers.

[KrombopulosRyan]

Calj737 - Something tells me you're going to be right. That was some motorcycle whisperer stuff right there.

Deltarider - You're right too, I'm for troubleshooting it all the way down and learning everything I can. I'll take a look at that video and see if a visual inspection yields anything.

jlh3rd - The electric starter does work, I took a few resistance measurements around the ignition, but I'd really like to go through the charging system and make sure it is doing it job properly. I'm looking for some reading material that can get me started on that.

PeWe - I will check those connections, and make sure that's not the issue. Seems plausible as this has been a very intermittent issue.

evinrude7 - Going through the points is definitely on the agenda today.


All - 4into1 sells condensers for $3.50, I'll order one and see if the problem disappears. If it does then I'll go ahead and get a Pamco ignition as people seem pretty happy with those, I've had a hell of a time finding a place that sells something other than Daiichi points and condensers.
Where do you guys get your replacements? Or do a lot of people on here have Pamco ignitions?

[KrombopulosRyan]

It might bug some, but I ended up ordering a pamco ignition and a new reg/rect combo. I had one on a 360 I owned a few years back and didn't have a single issue with it. I was struggling to find TEC points AND condensers, ebay had some points but nothing with condensers. Need the bike up and running as soon as possible and so why not set and forget.

Earlier when it was running on two cylinders I tapped on the condenser nothing happened. When I connected jumper cables, all four cylinders began firing.

Went to eat dinner, came back and set up my camera to do it again on video, but everytime I crank the engine over all four cylinders would fire. Took it out for a test ride and didn't have any problems.

I'll report back when I put the parts on and get some miles on it. Thanks for the help guys.

[Gene]

Hope it works out. Sometimes the easiest solutions are the best solutions. Didn't read the entire thread, but, yeah, Daichi is, unfortunately, #$%*e. Your points may have been fine. But, good luck.

[scottly]

Diagnosis can't be made by just blaiming a brand. Some people have no problems with Daiichi.

Tell that to FatMatt, and while you're at it, ask him about the Power-arc brand ignitions.

[KrombopulosRyan]

So I got the Pamco ignition and reg/rect that I ordered yesterday!

I started by adjusting my valves to the spec in the manual.

Then I installed the reg/rect.

Before I installed the Pamco ignition I took it out for a quick spin and made sure everything that I had just done was fine.

Good to go. To my disappointment when I get to the step (5, when you start connecting the ignition wires to the bike) that says the bike should start, the starter motor cranks fine but it doesn't start.

So I start poking around to hopefully find an issue with my install. Nothing..
Checked my battery, 12.8V
Jumper cables, no start.
I tried switching the green wires going to the coils.
I made sure the rotor wasn't 180 degrees out. Switched it. Put it back.
Switched the green wires back to their original coils just in case.
There is no pin on the advancer shaft so the rotor sits flush on the the advancer plate.

I've verified that there is no spark by putting the plugs in the boots and laying them against the cylinder head.

Spark plug boots are the NGK 5k resistor type.
I'm using the stock coils that ohm out fine and were functioning earlier in the day on the old points system.
Good connection to the frame on the black wires.
12V verified on the red wires.

The red wires are connected to the G/Y wire going to the rear brake switch.
The black wires are connected to the frame where the battery negative terminal is connected to the frame.
The green wire on the right side of the ignition plate is going to the right coil (1-4)
The green wire on the left side of the ignition plate is going to the left coil (2-3)
Also I'm not IPC certified or anything but have a lot of experience inspecting PCBs, nothing stands out when I look the ignition plate over.

I sent Pete an email last night, and checked the forums for any helpful information, nothing..

Waiting to hear back from Pete, not sure what else can be done.