Topic: Troubleshooting a 550K. *New brass vs. old brass on page 4*

[turboed13b]

Have you looked at the needles? I am reaching here but maybe #1 was accidentally clipped down causing it to be rich. You could always try moving the clip up to lean out the mixture some and see if things improve.


I am actually in the same boat with a 500 a friend just bought. Randomly the bike will idle very low like it is flooding out and sometimes stall. I dropped the needle twice so the clip is second from the top. It now can idle at 1000 without the idle hanging like it used to do but it still randomly bogs down where the rpm doesn't register on the gauge but it doesn't die anymore.

I am suspecting one of the float needles is not operating correctly 100% of the time. I have taken the carbs off and checked the function of them by blowing through the fuel line while the carbs are upside down and they seem to be sealing. However I am only testing them once and the bogging on this bike occurs randomly so I might of tested it while it was working correctly. Bought new float needles for it anyway and will see later this week if it fixes it.

[RAFster122s]

All carbs have very fine passages in them that influence the fuel draw on the idle and main jets. These air passages can flow some fluid and still be blocked partially.  So, while having brass that is genuine is important and having undamaged brass is also very important.  Gas, even old leaded gas would leave deposits on the brass.

Running my cx500 CV carbs through an industrial ultrasonic using purple Simple Green solution and chasing the holes in the brass with properly sized numbered drills made the bike run like new without having any stumble any longer as well as fixing throttle response across the board.  Like having a new bike.
Just don't want to have any brass show up on the material when chasing the numbered bits.

I think that you either have a partial blockage or the internal passage is damaged causing the issues.
Clean it and see if that helps.  Or, replace #1 with another clean carb body.

[Scott S]

 I haven't looked at the needles personally. I pretty much trust the guy I had do the carbs. He's done many sets for me and I've had no problems. Plus, would the needle really affect it at idle? It seems to run once I get off the slow speed circuits.

 I'm with RAF; I think there's a blockage, damage or corrosion with the low speed circuit. Particularly, number one.

[calj737]

But sometimes it will sit there and idle normally, only to cut off like someone turned off the key. No coughing, stumbling, spitting, dying, etc. Just OFF. Then it'll fire right back up.

 I'm now leaning towards a carb problem. And I believe that it's in #1 alone.
  once).

These two conditions can not be true. If a single carb is acting up, the entire bike will not suddenly die. I know you know this, but you are not looking at the big picture.

I agree with you, your #1 carb is out of whack somewhere due to its irregular firing. However, that alone can not and does not resolve the sudden disruption of a solid idle, a high idle, and immediate termination of the engine.

For the high idle/immediate quit, my inclination is to turn your attention to electrical/ignition. I realize you have replaced everything from the plate to the plugs, so that would say a power source problem (meter all leads, grounds, running voltage) or examine the advancer mechanism. Is it functioning properly? Is the stud tweaked?

I'm helping DusterDude chase a very similar issue on his K1. He's got other variables contributing, but proper exclusion of causes is as much the root of troubleshooting as determining the contributors to the problem. 

For your carbs: if the brass is all perfect (checked), the fuel level is perfect (checked) they synch up equally (checked) and they generally run well, then your attention has to be oriented to ignition behavior and the power feed of it.

I would be very interested to see the behavior of the battery, regulator and rectifier, and the stator output during these moments of "suddenly dying". It almost sounds to me as though the bike "quits" electrically due to a component heating up. But since you've replaced nearly everything, which one? Move backwards in the chain of the power source is my advice.

Sorry for the long winded reply, but sometimes the forest for the trees is the correct focal point 

[Scott S]

 No, I appreciate the response. And I've often heard that "99% of carb problems are electrical", which is why I went ahead and replaced the coils even though they seemed to test out fine.

 I agree that the sudden dying seems like an electrical issue. But the random high idle, low idle, normal idle thing doesn't. And the #1 plug looking different than the rest and having fuel on it doesn't either.

 I can say that I personally inspected the advancer. I checked it out thoroughly when I installed the Pamco. It's one of the nicest I've personally had. Springs snap back nicely. Tiny bit of lube before reassembly. I've checked the operation on the bike by snapping it back and forth and I can't find anything wrong with it.
 But...like you, I suspected it as a possible cause of the random high idle. But I just don't see anything to point to it being the culprit.

 It can be very hard to diagnose an electrical issue, especially when I'm working by myself most of the time. I have checked output of the charging system and it's working. When the bike does cut off, it fires back up almost instantly.
 I've swapped plugs, caps, coil leads and now coils. I triple checked all the connections for the Pamco when I installed the new coils. I triple checked timing, both at idle and advance. I've triple checked valve clearances. I even removed the air cleaner and stuck my hand in the air box looking for any kind of blockage, even though I'm the one that installed it and I knew there wasn't anything in there.

 The carbs were bench sync'ed and the vacuum sync'ed twice. The bike doesn't have that "clunking - knocking" sound like they do when the carbs are out of sync. BUT....until I get it to be consistent on start up and at idle, I can't say that I have them perfect just yet. Only because the bike is inconsistent during that phase of tuning.

 I have a pig tail for a trickle charger hooked to the battery. I might see if there's a way to hook up my multi meter and tape it up by the gauges so I can watch voltage when trouble shooting.

[calj737]

Yep, that's why this issue is so dang frustrating!

We agree, you have probably 2 unrelated issues causing different symptoms. The #1 carb is causing plug problems. Something else is causing the idle/interruption issue.

I've read carefully all your steps and I can not say you've overlooked anything. But, I would still work backward from the ignition towards the battery. I suspect, but can not say why, there is an electrical anomaly occurring that is killing the bike. With the Pamco, you might ask Pete for his insight, "is there a situation that can cause the triggers to fire irregularly related to electrical voltage?"  If there is, it's got to be an unusual one. I know his uses magnets (DusterDude has the same setup in kids K1). But the two of you share similar issues with different bikes, different induction and exhaust systems. But something is amiss (in my opinion) about the ignition programming.

I'm NOT disparaging Pete or his system. I'm simply speculating that both of you have something odd that is causing an improper operation of his system, not that his system is causing the problem.

[Scott S]

 I know enough about the Pamco to know that they either work or they don't, pretty much. I limped my XS650 home one night with less than 6 volts on a dead battery. The Pamco takes very, very little voltage to run.

 Plus, Whiteorbs was having issues with this bike before I bought it. Trouble with fouling plugs. That's why I basically started from scratch with the tune up and ignition system. He was running points.

[calj737]

I agree, the Pamco is a very reliable system. I'm not suggesting otherwise. But since Brian and you have the same issue having changed all the ignition parts, the problem (in my opinion) is further up the line. Something is causing the Pamco to misbehave. It's not the unit, it's what feeds it.

Hey, I could be dead wrong. But if you've addressed everything from the carbs and ignition/plugs, wires, and still have a problem, it's got to be pre-ignition, right? It could be as menacing as a floating bad cell in the battery. Have you had it load tested? Did you use an inline fuse to the Pamco? Maybe confer with Pete if you can reduce the amperage of it by half to see if you get a fluctuating line voltage to the Pamco? I'd want something to "trip" to lead me in the proper direction of assessment.

If static tests of your electrical/charging system show no obvious faults, then it comes down to heat while operating. Have you done a resistance check along the ignition paths? Perhaps you have a poor connection that provides power, but too much resistance under load to create stable current. Again, speculating. But it's bound to be something amiss in the power feed.

[Scott S]

 Electrical trouble shooting is my Achilles Heel. I'm very weak in that dept.
 BUT....let's say I find the reason for the seemingly abrupt cut-off. That still doesn't explain the low speed operation of the #1 carb and/or cylinder.

 I pulled the carbs and they're spotless. The bowl is clean enough to eat off of. I can shine a light and use a magnifying glass to peer down into the hole for the pilot and I see no obvious corrosion or build up. I can spray carb cleaner in any direction and get a good, clean flow.

 The slide on that carb isn't up or down any more than any of the others. In fact, the #4 carb may be raised slightly more than the rest, if anything, but that's because I moved them around slightly while vacuum syncing.

 I'm about to start a crap-ton of overtime at work, so I don't know when I'll get a chance to swap over the other bank of carbs and try it again.  I also have an email out to Harisuluv and I'm waiting to hear back from him.

[Scott S]

 Even though I can see the tappets move and I haven't seen anything really odd during the valve adjustments, is there anything with the cam that could cause this type of issue?

 A worn lobe that's giving odd lift at low RPM or something?

[calj737]

Regarding your carb anomalies, I've no clue. You've done everything possible at least three times to confirm their operation. This is why I'd turn my attention to the ignition side. It is still odd that only #1 is being adversely affected from an A/F perspective though.

But since it's the first cylinder in firing order, perhaps it is being victimized the most during the electrical anomalies?

[Scott S]

 I think I may be on to something....

 I pulled the old carbs out of storage and pulled a bowl to check and make sure they were clean. I also took a quick look at the bench sync to make sure I didn't have anything way out of whack from vacuum syncing them to a different engine.

 That's when I noticed that at rest the slides were noticeably lower on the old carbs. This would explain why I had trouble getting the idle to cooperate on the "new" carbs. I could only go out maybe one turn and then the idle screw wasn't even touching the linkage. Two turns in and the slides are open TOO much.

 I think I need to go in a few turns on the idle screw and re-bench sync the "new" carbs. Get the slides down lower and then see what happens.

 New slides


Old slides


 New idle screw


Old idle screw


New


Old

[turboed13b]

I haven't looked at the needles personally. I pretty much trust the guy I had do the carbs. He's done many sets for me and I've had no problems. Plus, would the needle really affect it at idle? It seems to run once I get off the slow speed circuits.

 I'm with RAF; I think there's a blockage, damage or corrosion with the low speed circuit. Particularly, number one.

The needle affects all range of operation.

[Scott S]

 I won't proclaim victory just yet, but that seems to have done some good. I raised the slide a lot in order to gain some operation on the idle screw. Dropped them back down to a very tiny opening and bench sync'ed them.

 I haven't put the gauges on it yet, but it holds an idle for longer than it ever has. Just the teeniest, tiniest bit of hang before dropping back to ~1100 rpm. I'll check the manifold clamps once it gets some heat in it and tune it with the air screws. Even as is, it's not enough to really be an issue.....just not 100 percent crisp on the return.

 The #1 pipe is still ever so slightly cooler than the rest at idle, but only by a few degrees.....not 20-30 as before. Under load, they're all pretty even.
 I can get 2 to 3 passes up and down my street before the bowls start running empty and the idle wants to climb, but until then it runs great.
 I did notice that as they ran empty, the idle would jump up when I pulled in the clutch. Then, as they neared empty, it would just stay up. I'm attributing this to a lean condition as it's running out of gas. The only way to really test it out further is to mount the tank and see what happens.

[Scott S]

 It seems to me that all your cylinders are rich and to compensate you have have to adjust your idle screw way open. When you do this you loose the vacuum to pull in fuel which cause a lean state and high idle. eventually the slows will catch up and flood out the carbs and this is when you see the idle go back down.

In the picture it looks like the plug on the left is not igniting because it is so clean. Last time I had a plug like that it was from the carb flooding out because of a small rust particle that was blocking the float needle.

 This...I believe this is what was happening but more because of the slide positions rather than a corroded or worn jet or passage.

[turboed13b]

Yeah having the slides open that much will cause a hanging idle. All of mine are barely open almost like your old slide picture.

When I bench sync I make sure the slides are fully closed when the idle screw is backed out all the way. Also you should be able to kill the bike by backing out the idle screw. If it doesn't die then you have the slides open too much during your bench sync.

[Tews19]

Good for you Scott! Looking forward to hearing the final outcome.

[calj737]

And do you think this effected the sudden shutdown?

[turboed13b]

And do you think this effected the sudden shutdown?

I can see the bike have a sudden shutdown if one plugs becomes fuel fouled.

[Scott S]

And do you think this effected the sudden shutdown?

 All I can say for sure is that it hasn't done it since I made these changes. I didn't spend a whole lot of time on it, but it idled longer than it ever has without the idle either going crazy or cutting off.

 I'm trying to decide whether or not to put the gauges on it or just run it with the bench sync.

 I need to reassemble the gas tank (after paint.....cap, petcock, badges, etc.) and get it back on the bike and take some longer rides with a good fuel supply and see what happens.

[calj737]

And do you think this effected the sudden shutdown?

I can see the bike have a sudden shutdown if one plugs becomes fuel fouled.

That would be highly unusual. These bikes will limp him on 2 cylinders, certainly 3. Shutdown without a hesitation for a single plug fouled? Ummm, I'm skeptical.

Here's to hoping she is reliable now, Scott!

[turboed13b]

And do you think this effected the sudden shutdown?

I can see the bike have a sudden shutdown if one plugs becomes fuel fouled.

That would be highly unusual. These bikes will limp him on 2 cylinders, certainly 3. Shutdown without a hesitation for a single plug fouled? Ummm, I'm skeptical.

Here's to hoping she is reliable now, Scott!

I am just speaking from experience having over 10 bikes in my friend group I have seen  a whole array of problems. Running on two and three cylinders is extremely hard and definately won't idle without  a lot of throttle manipulation.

[Scott S]

 I took her (him?) on it's maiden voyage tonight. It'll idle really well at an indicated 12-1300 (doesn't really sound quite that high, but it sounds "right"). It pulls HARD past half throttle and on the top end.
 It seems a little choppy right off idle and in the lower circuits. I think I can hear it being   choppy or breaking up a little at part throttle, but I'm not real sure. New bike, new helmet...never heard the stock 4-4 pipes before...etc., etc.

 It wants to load up and sometimes stall when coming to a stop. I have to feather the throttle or clear it out, then it'll idle just fine.
 I went from 1.5 turns on the air screws to 2, and that seemed to help. Tried going to 2.5 turns....which is one full turn over "base" settings...and it didn't improve.

 I think it's acting like it's rich down low. I haven't pulled a plug since I got back. I should maybe replace them all since, even though they're new, they're the ones I used for tuning on the fuel jug and I know that two of them have been fouled and cleaned on more than one occasion. All four pipes are hot and seem to be running together.

 Is it possible that I need to go IN on the air screws and fatten it up some?

[rb550four]

I was running through your thread, and saw in reply 17 a tore up 38 , which carb did that come from? Did you get another one to put in that was in better shape? Did the replacement seat properly,not just by stopping ...but by stopping all the way in? Could there be left over brass stuck in the hole that would allow free fluid passage but not allow the replacement to seat right? You know where this is going right ? Have you taken the replacement out since installation to check for similar damage as the first one had? Does this sound as confusing as I think it might? Everything else is sounding like it was done correctly then checked again except for this. Was this problem in carb #1?
And just because.... I thought I might ask if you have and emgo ignition switch or a stock ignition sw...Was toying with intermittent type  issue as a possibility overall but not as major contributor to carb 1 problem. The long shot idea as intermittent prob would be an old fuse that should have blown but for some reason makes contact most of the time,longshot, but thought I'd ask.
 As I understand the 1.5  turn is the place to start on the air screws, I have also read that ,and I think I remember one of my bikes is set at 1 and an eighth turn...that jogged my memory because I just hated the idea of remembering to make a quarter turn then, turn it back half of that quarter...but I don't think that's going to help #1 either until the real problem is found.

[Scott S]

Well,  the #1 issue seems to have disappeared when I lowered the slides and re synced.
 I did replace that pilot net. I also cleaned and inspected the hole with a strong light and magnifying glass. It looks fine....no corrosion,  etc.

 As far as I know,  the ignition switch is stock, but that's definitely something to check. Along with the fuses.