550 Witchcraft

[jryftc]

My CB550 was running well, but with a little bit of boggy acceleration for the last 6 weeks. However, after a "longer" ride the other day, it was having acceleration issues. Thought it was overheating, but I let it cool down and Cylinders 2 and 3 didn't fire. Stalled out twice from stop, and couldn't make it up hills on the way back. At first, I thought it was a carbouration problem because plugs on the bike have fouled out before. I took the carbs off and set them to stock float height (12.5mm) and the air screws to stock setting (1.5 turns). Put it back on and threw in new plugs, and cylinders 2 and 3 still weren't going. All the physical coil wires have spark without boots, but 2 and 3 may have a little bit of weaker spark with boots. Regardless the bike ran fine with the setup in the past. This is what the plugs look like. First plug is from cylinder 1. Just the contact point is black. Second picture is from the second cylinder, which doesn't look like its firing at all. Another weird thing I noticed when I looked for dirty points is that points 1 and 4 have less consistent spark between them than 2 and 3 (see last picture). I don't know if this has anything to do with it, but I feel like this problem may be electrical. I know there's like a firing order, but on my bike I have had all cylinders running as is. Curious as to what it is, maybe a shot coil? My buddy suggested something about valve clearance or something coming lose while riding. I don't know how it could be carbs. I'll also post a youtube link of it running. Just to reiterate one more time, this happen during a ride. Thanks in advanced for any advice, sorry if I said anything wrong. Never have worked on a four cylinder bike.

Joe

PS here's a link of it running on 1 and 4 currently:
https://www.youtube.com/watch?v=al8yXpuuQRo&feature=youtu.be

 

[dualitymike]

I would say it's definitely an electrical problem, either with the points for cylinder 2&3 (the one in the front) or with that coil, since one of the coils fires cylinder 1&4 and the other coil fires cylinder 2&3. It's really hard to test a coil since sometimes it will short out only after it gets hot, but you can at least test the primary leads for resistance. I'll see if I can post a how-top on the subject in my next post.

 

[jryftc]

thanks for the quick reply. I read that 550s and 750s have this problem sometimes, i think 2 and 3 not firing but 1 and 4 going fine in addition to signs that the carbs are "okay" are pointing right at coil as well. I mean the bike was on four cylinders...and all I did to the carbs was clean them and barely touch floats/reset screws. Plugs aren't wet bowls don't leak, no wet plugs, etc. The plugs I was running were fouled out but who knows how long they were in there. Just weird that this would happen riding, or maybe it was dragged out over time.

 

[jryftc]

So where would you go from here, just grab a new coil? what would problems with the points entail? the advance spring or something went? I've never done anything with a four cylinder engine before so apologizes if what I said about the points isn't right.

 

[carnivorous chicken]

Don't know why you started another thread with the exact same problem you were describing in the other one, but there you go. Rule out points/condenser first before you buy a new coil, unless you like throwing more money at a problem than it might take to fix.

 

[jryftc]

I started a new topic because your advice consisted of nitpicking what I wrote and telling me to rebuild my carbs, which I knew didn't need to be done. My reluctance to pick up a wrench was from a long winter of doing nothing but, which I clearly stated. Was hoping posting under a different topic with a fresh date would lead to someone else pointing me in a different direction and would be more pleasant to deal with. Thanks man.

 

[crazypj]

If ignition is left on coil can overheat and breaks down. Pretty common, you may be able to see insulating material coming out

 

[jryftc]

Thanks PJ. Could this happen with the coil yet the wires coming from it leading to the boots still have spark? I have spark coming out of the wires leading to the boots.

 

[Brodie]

My first car had coil issues. It would run fine and then break down like it had no fuel, then pick up again. This went on for a while until it just gave up. Ended up having "goo" leaking from the coil.

For an easy visual check it is worth having a look. Coils are not to expensive to replace anyway.

 

[crazypj]

Reminds me of my first car, Rover P6
It ran great at 85~95mph but missifred like crazy or even cut out at idle.
Condensor 'stopped working' when hot ;D
I didn't know as much about electrical systems back then (plus it worked fine when cold) so it took a while to find problem

 

[jryftc]

I'm going to have to take a look at it the next time I'm at my garage. Works been taking up a lot of time. So this is almost an assured electrical problem with the coils, points, or condensers? The first thing I'm gonna do is rule out the coil by switching it and seeing if 2 and 3 fire with the one that's working for 1 and 4. Take it from there. But I can essentially rule out carbs? Just to reiterate it happened while riding, and all four of the wires coming out of the coil has spark (without boots on, with boots it seems like there's less spark)

 

[carnivorous chicken]

I started a new topic because your advice consisted of nitpicking what I wrote and telling me to rebuild my carbs, which I knew didn't need to be done. My reluctance to pick up a wrench was from a long winter of doing nothing but, which I clearly stated. Was hoping posting under a different topic with a fresh date would lead to someone else pointing me in a different direction and would be more pleasant to deal with. Thanks man.

Shit, really? "Nitpicking"? So sorry to have offended. Good luck buddy.

 

[jryftc]

Switched coils around the other day, and it didn't make a different. The bike didn't start at all. Plugs 1 and 4 also started looking a little bit white on the top, but black on contact point while 3 was wet. It looked like the carb on cylinder 3 was also spitting a little bit of gas. Before I get back into them I'm going to check the points and condenser, if not pull em again. Fingers crossed this will not end up being a problem with the engine. Thanks again for all the feedback.

 

[Sonreir]

Let's not open multiple threads on the same issue, please.

Locking this one down.

You can continue the conversation back at the original thread:
http://www.dotheton.com/forum/index.php?topic=66155