Topic: A sputtering CB550 needs a BAND-AID.....

[thebeekeeper]

Howdy. I'm sorry this is long winded. I know of no other way in my youth.

I mainly posting this because:
A.) I like you guys and I read the forum often without participating. Now's a good time to start.
B.) I think troubleshooting is fun and sometimes my talking/typing things out helps the process.
C.) I know next-to-nothing compared to 99% of the people who frequent this forum and I would hate to waste (for my purposes) an unbelievable resource by not asking questions.

I was riding the other day (maybe 40 degree F) after a spring carb clean that I did for the fun of it (even though the bike was running fine). So, here I am scootin' up some forgettable hill and just as the bike is starting to warm up enough to upgrade from 'scootin' status to rootin+tootin+scootin status it begins to sputter out on me. The bike faithfully brought me home on the one condition that if I be gentle with her, she'd bring me back at her own pace since any throttle at all would practically kill the engine. Because I would ask, yes, the tank had fuel-a-plenty. Being it that I just did the carb dance, I went straight back into the carbs to make sure I didn't pull the ol' 'Doctor dropped his scissors during the operation and now patient Phil Dwith Regret has to explain himself every time he goes through airport security' routine. Because one can never be sure, I did that twice when the first attempt didn't fix the sputtering/cutting out at any RPM above 2K. I could eat off of those carbs and, if I were tiny, I could crawl through all critical passageways/jets etc without needing a pickaxe.

Then, I try the bike again and find that I can run it through the RPM range with, say, 85% choke. Sounds like carbs, right? Well, that's what I figured so I cleaned em' again. Fired it up, same same. Plugs looked good. Fuel in the tank. Carbs are clean. All 4 headers hot. Then, checked spark... 1-4 looked noticeably weaker than 2-3 and even somewhat intermittent. Points are new as of a couple months ago (and remain properly gapped), and that's also the last time I checked the timing.

Well that was today. The bike is being stored at my parents garage and I won't be able to get to it again for a while so I figured I would come up with as many ideas from you guys as possible so I'm ready when I get back to it. Here's what I can come up with to check after scrounging through the forum:

1.) The 1-4 Coil, need to check the primary and secondary resistance for values that escape me now but exist in a post somewhere on here. I've never changed these in the 1.5 yrs I have had the bike.
2.) Condensor, someone somewhere said something about having an issue where his condensor would work until it heated up and then would being to fail. Also, not touched since I became owner.
3.) Valve clearances, also checked a couple months ago.

What the else could it be? Please lend me your knowledge!

Some info on the bike... 1975 CB550F. Uni pods and open 4-1 headers (ive spent an ungodly amount of time adjusting the carbs to compensate for this "lean-ing" condition and have had it running great for a year straight now). 115 mains with needle up one notch richer than stock. 1981 CB650 "63HP" cam.

I'm hoping people actually read this and respond despite it being waaayy too long for what could have been a small question.

Best,
Joshua

[dave500]

go over the ignition fully,and be sure its spot on before you tinker with carbs,you say you really opened it up?not excessivelly of course,it should handle high revs,pull the plugs ,check the cap resistance and the coils resistance.

[vames]

If it's running fine with the choke on, you might want to make sure that all your carb-to-engine boots aren't leaking. You can idle and spray some wd40 all over them. If the idle slows when you spray one, chances are you're sucking air.

[thebeekeeper]

Thank you, kindly, for your responses guys.

I started her up today and she sounded worse than ever. I spray WD40 around and noticed no change. Eventually I found that plug wire #1 had broken inside of its sheath and was causing the intermittent spark issue. So, that makes sense.

What doesn't make sense is that the bike would stop sputtering if I choke it. Anyone have an idea here? Is related to temperature in the cylinder due to inconsistent firing. Ive run on 3 cylinders before and it doesnt sputter/kill my bike like it did a couple days ago. Do I have multiple problems or are they related?

I'm gonna hit up some auto shop tomorrow and try to splice new wires onto my coils. I checked their resistances and they seemed great. Although, I will say that the spark looked rather weak all across the board. I pull the coils off an 1100 Goldwing in non-running condition in my parents garage and got fantastic spark out of those. Unfortunately the coils are huge and I couldnt see a way to fit them on the CB.

Thanks again for a help.

Josh

[bryanj]

DON'T fit the Wing coils they are not 12volt as the Wing runs a resistor in the primary circuit that is cut out when starting

[dave500]

What doesn't make sense is that the bike would stop sputtering if I choke it. Anyone have an idea here? Is related to temperature in the cylinder due to inconsistent firing. Ive run on 3 cylinders before and it doesnt sputter/kill my bike like it did a couple days ago. Do I have multiple problems or are they related?

a lean mixture is harder to light off than a rich one,if the spark is a little weak itll be even harder,with one wire down you in effect have two plugs out on these systems,the goldwing coils will show a hotter spark on full 12 volts,lots of cars have 12 volts to the coils on crank,but about 9 once you release the key to the run position,its done via a ballast resistor,this gives a hot spark to start but then relaxes the load on the coil once running as its really a 9 volt coil,this is done to allow for the voltage drop when the starter motor is used,the big wing engine takes a bit of current to crank so this system was used,if a 12 volt coil is used with 9 volts the spark is feeble and as soon as you nail it you get misfire or hesitation,if you use a 9 volt coil like the goldwings for running itll burn out,as itll be seeing 12 volts all the time.

[bryanj]

Check the state of your battery and if the bike is charging properly as what you describe is typical of a not charging properly 500/550