Topic: CB550 - Wont idle, cold cylinder (or start anymore)

[JoshuaJames]

Alright, i have been wrenching on this bastard for the better part of three years. she ran today, but wont idle. overall, very happy day. but now, i have the taste for blood, sort a speak.

kicks over relatively easily, wont idle though. cylinder 1 is cold (header), 2-4 are about the same heat level. see the video.

http://youtu.be/FUMbMv6rxTM

let me know what you think!

[harisuluv]

Congratulations on your progress so far!

The idle jets on these bikes are TINY.  Assuming you have spark to the cylinder that would be my first guess.  What have you done as far as troubleshooting so far?

[JoshuaJames]

thanks!

I have done everything, which is why i left it all out. figured i should start from ground zero so i don't overlook anything.

Electronic ignition.
advanced timing.
spark to all 4
compression is good
carbs have been rebuilt and cleaned (by me). cylinder 1 was slower on getting fuel, which could be my issue with that one.
fuel+air screws are set at about 1 1/4 turns out (factory is 1 1/8)
not sure how to set the main idle screw

any tips, or things i could check and post feedback to help along....

[greenjeans]

Hate to say it, but clean the carbs again.   They really can't be clean enough - especially if they've been sitting for any length of time.

I've restored about 10 of these CBs over the years and now, and the first thing I do is clean the carbs.   Then, they sit for months in a baggie to keep them clean, thoroughly lathered in seafoam.   Then, before I install them, I go through them again completely - with compressed air, all jets out etc etc.   Seems crazy, but really - they can't be too clean.

The first couple that I did all looked clean....  it was only after I cleaned them again (after suggestions here) that my problems cleared up.

If you are getting spark to all 4, then you only have air and fuel left...    What air filters are you running ?     And, as much as I hate to, I always buy new carb insulators air box boots, float bowl gaskets and float needles and seats.  Piece of mind.

Also - double check your float levels and the float valves.   The more accurate you can set the floats the better it will run.  It sounds like you aren't getting any fuel to that particular carb - a stuck float or needle would do that.   Do a search for a clear tube float level check.  Basically you just need clear tubing and some sort of modified screw to use in place of the float bowl drain screw.   I used some old screws and filed down the head just enough to get the clear tubing on there.  I'm sure there is something easier.


You're close.
You can also check your exhaust gaskets - probably wouldn't cause your cold cylinder but exhaust leaks make the carbs harder to tune and can lead to other issues.

[JoshuaJames]

great advice greenjeans! do you have any preferred readying on cleaning carbs (particularly with pictures as i am a visual learner) ? I have gone through them a couple of times, but i am completely new to this. I read thread on here all the time, but some times they contradict, or offer different solutions. Do you have one method, or thread, etc, that you trust?

No filters right now, but i have the stock air box set up. My impression was that i should be able to get it to idle as is (no baffle, no air filters). Then, once i want to tune the idle, i would put on my new exhaust (after figuring out how to deal with the broken exhaust stud) and the stock air filter.

I will look into the clear tube test for fuel level. I know i measured and set the float levels, with a second set of eyes to be sure. I will use this method to check. great tip on the exhaust gasket (i know this is an issue on my bike) and the

[Killer Canary]

Once you've got the bowls off, flip the carbs upside down and put a drop of liquid( WD-40,  carb cleaner) on the slow jet hole. It should seep down the hole. You're not just checking the jet, but all the passages associated with it.

[JoshuaJames]

clean the carbs, very thoroughly. floats are all even, all four cylinders fire now.

Took off the manifold, and gave them a good cleaning, and soak in seafoam. replaced the o-rings (also replaced the o rights for all tappet covers). made sure all connections where as air tight as possible.

she fires, and seems to run a little better when i rev, but as soon as i let go of the throttle, it dies.

any suggestion is welcome!

thanks everyone.

[rb550four]

If you've done what you say and all is good....have you sync'd your carbs?
You may want to finish up those loose ends like  the exhaust gaskets, put the filter that you intend to run with in it and the exhaust system that you intend to run, recheck your spark timing , recheck your air screws ,fuel petcock for cleanliness, then sync the carbs.

[JoshuaJames]

I have synced the float levels and the throttle slides. Is there anything else to sync?

[rb550four]

No but you should go through all systems including lubing the spark advance ( if you are using one) just to make sure it is operating free and properly, if nothing else , you can rule some things off the list of potential problems.
Did you mean bench sync  (visual) or vaccumm sync ( on gages,running)? Bench sync can get you in the ballpark, but is nowheres near accurate enough to run this machine correctly.
I set my air screws at 2 turns from bottom and work them back while running.
Electronic ignition, , can be altered a degree or two...
If it was me , I would put everything ( complete the way it will be driven) on the machine and tune it then.

[JoshuaJames]

bench sync. cannot afford gauges and do not know anyone that has them.

no spark advance.

i have work on the carbs so much, including with a more experienced set of eyes/hands, that i am not sure the problem lies in the carbs. but, based on searching forums, it seems that they are they only thing that could cause this issue.

can any of these play a factor:
exhaust
electrical
start (just guessing)
the engine itself
low fuels (running without a tank, just keep filling the carbs in between starts using an auxiliary tank).


before i pull the carbs off again, i would like to cross everything else off the list

[rb550four]

Sure all that stuffs factors in , non stock exhaust... up 2 jet sizes
                                               Pods or no air filter?  up another 2 jet sizes
                                               5 degrees on the timing , accurate? Does it smooth out at 4 or 6 degrees?
                                                Low or inconsistent fuel source, That'll be a problem
                                                Unsealed exhaust, problem
                                                 Are your plug caps on tight? Are the plugs fresh,gapped properly?
Every thing makes a difference. And it sounds like you are on the right track for hunting it down.Good hunting.

[JoshuaJames]

stock pipes, air filters. electronic ignition, so not sure about the timing degrees you spoke of, but i set it by the book.

here are what my plugs look like, someone on another form asked to see, so i thought i would share here as well, in case that sheds light on anything.

[rb550four]

JJ,
 Everyone wants to hear that your machine is running great including me. But I think that you are rushing it, meaning that it's just not ready for a final tune yet. you need to button up every loose end and make that bike exactly the way that you will ride it... with air filters, exhaust gaskets, etc.... all that stuff.
 You say you have fire to all 4 cylinders, excellent , now be sure that the spark happens at the right time. Then Spark is done. Go on to the next thing.
   Fuel source . This has to be consistant ! Filling up a couple carbs for a while is not a constant feed/even flow, you can't expect even the cleanest carbs to act properly when you are starving them intermittently. Make corrections and go to the next thing.
    Air  . Filters stacks ,or pods . stacks/pods/no filter will allow more air than stock filter.  Anything but stock filters will change the air/fuel ratio into the engine. Got too much air ,need bigger jets to get a correct ratio. usually up 2 jet sizes .
The exhaust also plays a part in the air scenario . Headers reduce backpressure and increase air flow, rule of thumb up 2 jet sizes for nonstock pipes. On to the next thing
   which is really the culmination of the last 2 things, synchronizing the carbs. meaning that the correct amount of air and fuel going through each carb is equally metered between all 4 cylinders according to the amount of vacuum of air being drawn into the engine. This is not possible to do by eye or by ear, it takes gages.
  As for the pic of plugs, they will continue to burn different from each other as long as all 4 cylinders are allowed to be  working differently from each other, in other words, your engine is out of sync. And you can't expect a motor to run right when it is allowed to run in a not right mode. Your plugs are not the cause, they are a symptom.
  Call a shop and get a price on syncing your engine or buy the gages, your motor won't be running correctly until you do.

[dirtdawg]

Have you done a compression check? If spark is good and plug is wet, may be a hole in piston or value stuck open.

[JoshuaJames]

great advice rb550! i have done everything you listed, except the carb sync, i will look into that. currently unemployed, so a shop is not an option. going to ask around and see if anyone has some.

i have stock air filters, and exhaust on there now (haven't tried it yet). going to check the timing again.

dirtdawg, yes, i have done a compression check. a while ago, so i do not recall the numbers, but i know they were good.



today is going to be a day in the garage, so hopefully, i will have progress to report back.

[LesterPiglet]

There are guides on the forum about making your own gauges. This is the first one I found using the google custom search.

http://forums.sohc4.net/index.php?topic=107357.0

[JoshuaJames]

got my new dyna ignition in the mail. trying to set the timing, and having issues. it will not get to full advance. i searched this form, and SOHC4, and cannot find something with this issue, and the solution. I have a home made timing light set up.

any ideas?

[rb550four]

Remove the points cam from the advance assembly by twisting to the right and pulling.

On some 550 models ,a small pin will be seen projecting from the 1-4 side of the advance assembly shaft. This must be removed, and can be , by gently tapping on the side of the pin with a screwdriver and hammer.

Coat the assembly with shaft oil. While holding it to the 1-4 side pointing up, slip the rotor over the shaft. A magnet about 1/4 " diameter will be noticed  on one side of the rotor. This magnet must face to the left when the 1-4 side on the advance assembly is pointed up. Spread the weights and push the rotor down until it engages the weights. Ensure the rotor rotates freely on the shafts the advance weights move out and back.

Install the advance /rotor assembly on the engine making sure that the pin at the end of the assembly is engaged in the pin hole in the crankshaft. Reinstall hex washer and 10mm bolt and tighten Ensure that the rotor is still free to rotate.

Install the 3 plate screws.

 Hope that helps.

If you need the electric instructions,let us know. or www.dynaonline.com

[JoshuaJames]

thanks RB.

i have the instructions. the problem is, the plate does not turn far enough to get the fire lined up with the advance timing. i have seen a couple post about turning the rotor by hand (to the right), so it is fill opened, then sliding the plate until it fires.... trying to find a video on this process, but no luck.

i will keep messing about until i find a solution that works.

[rb550four]

Are you sure you didn't put it ( the rotor)  on 180 degrees backwards ? It would be easy enough to do. Give it a try and see if your test light comes on for 1-4 while still  on the plate within factory adjustments.
Another thought... do you have your test light up the 1-4 plug while testing the 1-4 for time?
Yeah , it sounds silly but these things do happen.

[JoshuaJames]

i have installed as per the instructions . rotor moves freely, no rust, no gunk, all perfectly clean. springs move freely, everything turns free.

rotor was set up properly, with the magnet to the left when 1-4 is up. timing is close, but it is firing almost halfway between the standard timing marks and the advance timing marks.

i am looking for a video, photos, or diagram on setting the timing with a dyna S.

i will report back tomorrow once i get another crack at it.

[JoshuaJames]

the timing light comes on when the plate is in two different locations (see top screw). this cannot be right.....

[JoshuaJames]

okay, so you have all been very helpful and I appreciate it very much!!!! without a doubt. The responses i have received have been informative, educational, and helpful. That being said, she is actually not kicking over at all not. just burping, not fire like she did in the video...

I am going to do a dangerous thing, and make assumptions. Based on all your advice, and my experience, and going over this bike everyday for a week, i do not believe these are the main culprits:
1. exhaust (running stock, 100%)
2. air filter (stock)
3. actual spark plugs or caps. non resistor Honda plugs, resistor NGK caps. 5ohm. all new. wires were cut for fresh connection
4. dyna ignition (not timing, but actual device)
5. battery. holds a steady charge at around 12.2 v.

These could all play a factor in the tuning, and getting to run efficiently, but i have to eliminate some things in order to have a chance.

Here are what I want to focus on
1. Carbs (asked a local mechanic for a quote on rebuilding)
2. Dyna Timing (at a loss here, timing light comes on at multiple places on the timing plate, see previous pictures)
3. If I am getting enough Spark (not sure how to test this, any ideas?

i am currently unemployed, so time is not a concern. any advice, tips, etc, would be greatly appreciate. Also, i am a visual learner, so photos or video are GREAT).

thanks again!

[JoshuaJames]

i advanced the timing as far as the timing plate would go, then, i moved the pick ups using the allen key as far as they would go (all counter clockwise). The timing is now as 'advanced' as dyna and my bike will allow (without mods), and it is still firing in between regular timing and advance timing.

what am i doing wrong?

I used static timing, as per a blog i found on the issue. I did not rotate the rotor at all. when i have set the timing by rotating the rotor ,i get multiple "firing points" as shown earlier in the trhead. when the timing plate is half turned it fires on the advance lines, and when it is all the way it fires on the advance lines, and wont start either way.....