Topic: CB550 - Issues for beginning rider - Help please!

[Koonendez]

Alright so I'd like to start by trying to give as much information about the bike as possible, but please understand that I had outsourced all the work on the rebuild because I didn't have the time to do any of the work myself while I was working. I have since changed jobs and have much more free time on my hands so that I can begin to really learn about this bike as I go through the process of repairing issues.

The bike is a 1978 CB550K8. Stripped down to frame and completely rebuilt with mostly stock components. The bike is using Carbs off a 1976 and an intake manifold off a 1975 550. The "builder" replaced my airbox with Pod filters. I have OEM electronics on the bike. If you ask me what size jets I have no idea as I have never taken them completely apart myself other than when I stripped the bike down to frame to powdercoat.

Condition: The bike runs...in fact I've been riding it around town as well as commuting to work the past few days when weather permits. The bike will not sit idle without me holding the throttle very lightly. It will bog down and die everytime even when warmed up. I notice some days or at some times theres a lot of black smoke shooting out the exhaust. I have had two strangers tell me I'm running "rich" but do not know what that means or what to do about it. The exhaust is a 4-1 MAC that has been cut short just beneath my right foot. The engine also gets stuck in high revs while riding or in neutral after downshifting. It will get stuck around 3-4K revs and then drop to almost shut off unless I hold revs up at 1500.  I have the IMS turned out 2 full turns from sitting position and I have no idea where the "big idle screw" is in relation to where it should be because I keep turning the damn thing hoping that it will help with the idle and rev issues.

What have I done so far?: Not much unfortunately. I have used some Seafoam in the tank to see if that would help resolve any issues and it doesn't seem to have corrected much although I'm sure its cleaning something in there. I barely have any tools right now, don't have a garage as I live in the city, but these are all excuses I am ready to put behind me to get this bike in GREAT running condition.

Please help! Give me something I can walk through step by step to diagnose the issue and resolve it. Please understand that even the 3000 mile maintenance checklist is something I've already looked at and considered to be daunting. But am willing to do what I need. Removing the carbs and opening them up would be the last step I'd like to do in this investigation as it would take me a LONG time to learn that process and I need my bike running for work. Sorry that I suck at all this and the info is vague, but I'm ready to try and answer any questions to the best of my ability and get my hands dirty as needed. Thanks in advance to all you guys with your help.

Koon

[lucky]

Since you are a beginner you really need to get some expert help.
No motorcycle shop is likely to be able to help you.

With POD filters and stock jets and cut off exhaust it will NEVER run right.

The good news is the 1976 carbs are less complicated because they do not have the accelerator pump system added on. The slide needle is also adjustable.

With out knowing the size of the IDLE JET .MAIN JET, and slide needle position, you will never get  the motorcycle to run correctly.

The best thing to do is buy the stock air filter box and stock air filter.
Put some shorty mufflers on it at least to make some back pressure.

You need to get some help in your area.
Do not go back to the person that set this motorcycle up.

[Stev-o]

You may have multiple issues. Installing pods and cutting off the exhaust creates a bike that can be hard to tune, but not impossible.

If you paid this "builder", why dont you bring it back and have them tune it?

[Koonendez]

Lucky: The exhaust is not completely cut wide open as it does have a fabricated tip creating back pressure or at least some. The cut end is covered and has large holes drilled through if that gives you a visual. I have already spent a lot of money on this project and buying new exhaust, replacement airbox, and necessary components is a road I'd like to avoid as much as possible. Not to say I won't do it if necessary, but I'd like to see if I can tune and correct these issues with the current setup that is already on.

Stev-o: Thank you for your optimism and I'm glad to hear there's some hope. I have lost all trust in the builder and would rather not see his face ever again if possible. He blew my budget completely out of order and lost trust in me.

Thanks for replies guys!
Koon

[calj737]

Koon - I completely understand your frustrations with that "builder". And that is the issue after all, he's a customizers, not a mechanic focused on proper, reliable running, he turned your bike into a cool machine, but overlooked and neglected the requirement for a good, reliable running bike.

Your options suck: pull the carbs and get dirty and test, test, test. OR, find a mechanic in the area that really knows these older bikes and pay them to do it.

Mix-match fuel systems and exhausts can be set up to run well. But there is an eternity of variables and little adjustments to get it to really run right.

The hanging revs could be a number of issues. Could be cable routing for the throttles, could be poorly lubricated cables, could be jets, needles, etc. Sorry, no crystal ball on that one.

There are quite a few members on this forum from your area. Open a thread in the Services Wanted section of the forum, and seek a recommendation on a local, well respected vintage mechanic.

For real carb expertise, member Harisuluv is possibly the guy if you want your to take your carbs off and have them properly rebuilt. For tuning help, he and TwoTired and many others, will offer great suggestions for you to try. But those carbs are coming off the bike so the details of their configuration can be known, and then adjusted.

Probably not the answers you want, but the only options that are guaranteed to make this right. Do not become overly frustrated. Angry with the "builder", sure. He deserves it. But either go slap him about and make him fix it, or move on and get dirty or get the check book out. All the advice here is free, but you pay with sweat equity. Are you up for the work and grime to get it right? Nothing wrong at all with paying someone else to make it right. Lots of us do it, but be prepared to sift through a few mechanics until you find the "right" guy.

Take huge amounts of detailed pictures and start posting them up to aide in advice (if you choose that route).

Keep us posted with your progress.

[Koonendez]

calj737: Thanks for the reply. I forgot to mention my other woes with services as I had also recently had my bike serviced by another person, but to no despair the issues are not of his fault because he simply serviced my bike to get the engine back up and running. The first "builder" had it running but only for a day. The bike did not start up again after I brought it back home. Not sure exactly what the issue was, but after shoveling out more cash the bike is finally in running condition, but not well at all. I am done spending money out to others and would like to begin trying to service this bike myself so that I am not fully aware of what the issues are when more problems occur down the line.

I will begin with the basics first. I am heading to a parts store today to try and replace my inline fuel filter which seems to have some rust sediment built up in the filter and buy a spark plug socket to pull them and check to see what their condition is. I will also look in the Clymer for a list of tools needed to pull the carbs off the bike as I have a week ahead of rain and more rain so the bike will be sitting anyhow. A few days I hope will give me enough time to take apart these carbs and give them a cleaning(which I will have to search this forum for to see what a proper cleaning is). I will begin to take photos and post them up through this process.

Thank you guys in advance for your patience and help through this process. Even with all the woes and issues I am still very excited about owning this bike and seeing it everyday. I cannot wait to have this beauty running the way she outta be.

Koon

[Stev-o]

A rusty tank will give you issues and many guys have had issues with inline filters, personally, I would not use one.

Drain some fuel out of your tank into a glass jar to see how clean it is.

Pulling the carbs is a good first step, it is not difficult. All you need is a wrench and a philips screwdriver.

[calj737]

+2 on the tank inspection. That's an awfully important issue.

Here's some other very useful links from this site for manuals and documentation
http://www.sohc4.net/cb550books/

There's a HUGE amount of carb threads here. Take your pick... One thing, on the side of the carburetor body is a stamped model number. Look around for it. Knowing that is critical to insuring compatibility of parts.

A plug "chop" is another important test. When you buy plugs, get the correct ones, and get 3 or 4 sets. They're inexpensive, and with the testing you're undertaking, you'll need many sets. Also, oil filters. You didn't indicate what engine rebuild work was done, so unsure about a oil change interval or draining being necessary.

Here's another thread worth referencing. SohRon is doing a factory perfect rebuild. You'll have differences in your build, but you'll be surprised how much value in understanding the original/proper configuration is towards deciphering issues you encounter.

http://forums.sohc4.net/index.php?topic=86697.0

I'm in exactly the same place as you, but have access to better resources for unwinding bad "shop" work. I'll be exorcising the final few demons next weekend from those numb nuts!

[Koonendez]

Thanks for all the help already. I'll shoot a video today with the bike running and post it ASAP so that you all can get a better idea of what I'm working with and possibly diagnose the obvious issues first and foremost. Will post it up today.

[calj737]

Do also take some pictures of your cables, routing, and the behavior of the gauges while revving the bike.

[Koonendez]

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[Koonendez]

Sorry didn't see your reply before posting and taking video. Hope the video helps


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[calj737]

Sw you start the bike with the choke on off, but didn't see where you adjusted it after start. If it's still on while you're revving the bike, you may be hurting yourself. It sounded as though it wanted to idle fine, but then you began revving it. What caused it to start faltering, did you adjust the choke, or rev with the choke still fully on?

Correction: choke is off in the video, didn't have the full screen view first viewing.

[Koonendez]

I didn't adjust the choke at all. In fact I've been riding it that way as it's the only way the bike will remain on. If I adjust the choke at all the bike shuts down


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[calj737]

Not good. Time to start pulling your plugs. Replace them, then do a plug chop. Do you have an area where you can do that run? And are you familiar with the technique?

I understand it may be difficult to keep the bike idling without the choke, but for test purposes, with clean plugs, start it, turn the choke to half, when you take it off, close the choke fully. Keep the RPMs up to perform the chops.

Take pictures of your current plugs, numbered 1-4. Repeat with chopped plugs 1-4. Post those up as soon as you can.

Then we can get an idea which direction to go, once you pull the carbs and we get mains, needles and jet info from you.

And remember to inspect the tank. You may have a debris problem in the bottom that's allowing rust to enter the carbs worsening your tuning problems.

Pardon my candor, that exhaust is bolloxed. Plan on a replace after the carbs get sorted.

[Koonendez]

Thanks. I went to an auto parts store today but couldn't find a thin walled 18mm spark plug socket so I went to a Honda dealership and asked the parts department who told me they cannot order me any tools unless its for the use of the dealership.

Anyone know if Sears Auto centers will carry the parts needed? Also I am not familiar with that technique. Also, where can I find the spark plugs for these bikes? Would any auto parts store carry them? I will try and pull off carbs this Wednesday and get to dismantling them to the best of my ability. I assume I will need to remove the tank completely before I can pull carbs so I will empty the tank and look into a rust removal system and re-line the inside of the tank.

[Stev-o]

I didn't adjust the choke at all.

The choke is in the off position. After warmed up, it shouldnt run with choke.

Try adjusting the idle to 1500 after warmed up for at least five minutes.

[Bankerdanny]

The '76 carbs don't have a fast idle cam like the 77-78 PD series carbs do. So you need to use the throttle to keep the bike running until it is warm enought to run without the choke.

Check the condition of the rubbers that connect the carb to the manifold and did you replace the o-rings that help seal the manifolds to the head? Vacuum leaks could cause the bike to run very lean and not want to idle or run well without choke.

[Koonendez]

Stev-o: So can we clarify that the bike should or shouldn't be running in the position that I have the choke set on in the video? When I move the choke lever up even after the engine is warmed up the engine cuts off and dies

Bankerdanny: there are some days I fire up the engine and it idles at 900-1000. Some days like today it won't even idle unless I'm holding the throttle. I'm going to take carbs off and buy rebuild kits for each carb replacing all four O-rings as well as I'm unsure of whether or not they've been changed


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[Stev-o]

Stev-o: So can we clarify that the bike should or shouldn't be running in the position that I have the choke set on in the video? When I move the choke lever up even after the engine is warmed up the engine cuts off and dies

The bike should be run in the position shown in the video (choke off).

Choke is only used when starting a cold motor. 

[bender01]

Yeah I thought it was off too.

http://www.ebay.com/itm/Honda-CB350F-CB400F-CB500-CB550-CB750-GL1000-SPARK-Plug-wrench-socket-bar-/181405153566?pt=Motorcycles_Parts_Accessories&fits=Model%3ACB550&hash=item2a3c96f91e&vxp=mtr

[Stev-o]

Yeah I thought it was off too.

http://www.ebay.com/itm/Honda-CB350F-CB400F-CB500-CB550-CB750-GL1000-SPARK-Plug-wrench-socket-bar-/181405153566?pt=Motorcycles_Parts_Accessories&fits=Model%3ACB550&hash=item2a3c96f91e&vxp=mtr

I like this one better....

http://www.ebay.com/itm/HONDA-CB350F-CB400F-CB750A-GL1000-SPARK-PLUG-WRENCH-OEM-/121336663835?pt=Motorcycles_Parts_Accessories&hash=item1c403a8f1b&vxp=mtr

[Koonendez]

Thanks for clarifying. I was really nervous for a moment there thinking this was a much more serious issue.

Plan is to remove gas from tank and inspect for major sediment or rust. If necessary re-line the tank. Pull carbs and rebuild with kits and replace O-rings. Then I'll check timing and spark. I also will replace inline fuel filter just to be cautious


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[Stev-o]

Pull your petcock, it should have a filter, an inline is not necessary and may hinder fuel flow. 

I know it's a sore subject, but what exactly did the "builder" do.  I saw the video, I see a stock bike with aftermarket bars, rear seats and gauges.  Not much "building" there.

[Koonendez]

The bike was down to frame for several years and he put the bike back together with of few of his own touches combined with parts I had bought and sent to him. It did not end well as a budget that was set was completely neglected and did not inform of the adding costs he was placing on the bill. Doubled the budget given.


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