Topic: First bike - 1975 Honda cb550 - need help getting it running.

[anthem78]

I recently bought my first bike that had been sitting in a storage trailer for a few years. I've been cleaning it up a bit and slowly going through fixing a few things. The carbs were a mess so I had them cleaned, replaced the fuel lines, put in new plugs, pod filters (the airbox was missing when I bought it) and a breather filter. I cannot get it started. All four plugs are getting a spark and are gapped properly, I see fuel running down one fuel line but should it run down both? I checked the points and they were clean and the gap seemed fine. Fuel runs out of one of the carb overflow lines. I'm sure I'm missing something, but I was wondering where to start.

Is it still a problem with the carbs? Is it a fuel problem?

Thanks.

[Achmed]

The experts will be along shortly. I am not one but I do know that these bikes need at least a little juice in the battery in order to start. Obviously you will need almost full charge if you are trying to use the electric start. The engine does turn over, right? You can check with the kick starter. You didn't mention checking your battery so I would make sure it has at least 12.5 to 13 volts. Full charge is a little higher, I think.

It's fresh gas, right? If you had the carbs cleaned and there is still an overflow I would suspect what exactly got done if you didn't do it yourself. May the CB gods smile upon you!

[OldSchool_IsCool]

A couple things come to mind.  First, "F" models (aka Super Sports) have a 4-into-1 exhaust.  Your exhaust is 4-into-4 which is typical of a "K".  You can double check your serial numbers against the model descriptions off the front page of this site to be sure.

All the bike needs to run is properly mixed fuel/air, compression and a strong spark delivered at the right time.

Lets check fuel flow first.  There is a drain valve on the bottom of each carb.  Open each drain valve one at a time and catch the fuel with a glass jar.  Does each carb flow strong?  Is there any crap in the jar?  Work on any slow flow or cruddy carbs first.

Next, double check that the points are timed correctly, or at least are close.  Your shop manual has the instructions or you can search for them on this site.

Report back here once you are satisfied these two things are in order.

[1timduke]

Wow, lots to do! 
Achmed and OldSchool are dead on, here's some more...
Look in the fuel tank for rust, or in the carb drain tubes, if you've got rust, sorry to say, carbs may need cleaning again

Fuel should definitely flow down both fuel lines, at the same rate, look for a clogged filter or petcock or pinched fuel line.
You'll probably need new plugs, no telling how old they are.
Tappet adjustment is easy, and very important.
Static timing can be set on a non-running bike.
Look for rusty electrical connection on the ground strap and other places.
Fresh oil
And on and on...

Oh, and set the kill switch to 'ON' (Yeah, I did that, for like 30 minutes one day)

By the by, what sounds exactly is the bike making when attempting to start?   When you work the choke, does the sound change?

You've got a great bike and they're tons of fun to wrench and ride on, welcome to the forum.

-Tim

[anthem78]

Thanks for the input guys. And achemd, you were right, I checked the frame number and it is a 550K. I had been going by the emblems that were on the side covers. Thanks.

When I try to start the bike you just hear the starter turning over, and once in a while it sounds as if it's about to fire, but doesn't. And the sound changes when the choke is adjusted, as well as when the throttle is turned.

I did double-check the kill switch after I had tried starting it for 10 minutes or so and what was set to "on".

I'll check everything else listed and respond back when I can. A few questions (some may be obvious):

1. Is the drain valve the screw at the bottom of each float bowl? My clymer manual doesn't say.
2. What is a tappet adjustment? And where is the ground strap? I'm at work right now, so I'll have to check all this when I get home.

I've replaced the plugs and changed the oil. I pulled the tank off last night and checked the petcock and fuel ran out of each valve there with the fuel lines off, so I'll go down the lines and check the filters, etc.

I'll pull the carbs out too and clean them again.

And I'll do my best to time the points. I found that in the manual last night, so I'll give it a shot.

It's going to be fun once I get it running. Thanks guys.

Michael

[flybox1]

Anthem.
good luck on your troubleshooting.
sounds like you have good fuel flow, but as others suggested, check your fuel for debris.  it can really cause hell with your carbs.

here's another suggestion, and you gave it away in your post.  
if you've got fuel running out of one of the carb overflow tubes, your carbs need more work. if you had them done, take them back. get a list of what was done, but suggest you do them yourself as only you know what is right and what/how you adjusted.
its easy...get in there!
Clean, clean and more clean. Simple green, carb cleaner...etc. its ok to be anal and have OCD(obsessive CARB disorder).
pull all the press-in/screw in jets and emulsifier tubes, float valves/pins and make sure they are spotless.
set float height to spec. and double/triple check them.  
while you're at it, bench sync the carb slides. (do a search of this forum for bench sync)

good luck and keep us posted with your results!
fb1

[punch455]

its ok to be anal and have OCD(obsessive CARB disorder).

I thought that was pretty funny when I read that.

[Zaipai]

Not to derail things, this sounds very familiar. If it does not start after doing/checking what the others said, I would also check to be sure that the yellow wire coming off the points goes to the yellow wire on the coil and the blue wire off the points goes to the blue on the coils and that the black wires are connected to the kill switch properly. Also after trying to start it for a few minutes, check the coils if they are hot then you have a short on your points so you will have to make sure the wires on the points are insulated properly.  I don't have near the experience the others have so this is just one more thing if what they said does not work.
--{ Added later }--
Another thought, while a clogged carb, or a float that is not closing is bad and will keep that cylinder from firing, it wont keep the bike from starting unless all carbs are clogged or have bad float adjustments. I mean mine was like that and only running on 1 and 4 but it started and ran, poorly but it ran.

Pull the plugs and see what they look like.. Are they wet after trying to start it? If so probably no spark. The carb peeing on your driveway, will need tending to however you may want to start with the timing cause even if the carbs need work, if there is no spark the carbs might as well not even be connected..

Also when my carb did that after rebuilding them, I gave it a tap with the plastic handle of a med size screwdriver on the bowl and it has not done it since.   Again, just some thoughts..

And OCD is funny!!!

[Aaron Richard]

sounds like you are going to need to take the carbs off. Pay attention to the one that is peeing on your driveway your float might be set wrong or you may have something caught between the float needle (like rust) that is keeping the needle from closing causing it to overflow. Also check the brass tube inside the bowl for any hairline cracks or pin holes. Really make sure your timing is right, a friend of mine thought he timed his and it wouldn't start, he finally realize he was off 180 degrees. The little things are the ones that cause the most headaches

good luck.

[OldSchool_IsCool]

An important point with carb cleaning... make sure you put all parts back into the carb body they cam out of!

[davetheman]

did you check for rust in the gas tank?  i am having the same problem on a 1972 cb750.  i checked the plugs and cleaned the carbs and all that stuff.  i finally discovered that my gas tank is a bit rusty on the inside.  tomorrow i am going to hook up some fuel lines to a plastic bottle or soemthing  and clean the carbs again. if it runs after that, then i'll know it's because of the rust from the gas tank

[Bill Vaughan]

Mike,

It looks like you have a ton of good advice here and certainly enough to keep you busy for a while. 

That said, you mention the Clymers manual in one of your posts.  If I can add one thing it would be to dispense with the Clymers manual and go with a Honda Factory Service Manual - the one written specifically with your bike in mind.  Thanks to our kindhearted members, it's available as a free download on this website at this link:  http://forums.sohc4.net/index.php?topic=17788.0

[anthem78]

Thanks everyone. Here's an update:

I spent most of last night and today dismantling and cleaning the carbs again. I had a clogged fuel line between the fuel filter and carb, so I pulled that, put in new fuel lines and fuel filters and put the carbs back together. There was a hairline crack in the brass tube in the carb that was overflowing, so I picked up another float bowl from a salvage yard close to my work. Also did a bench sync. So hopefully that addresses the carbs.

I have not had a chance to adjust the timing yet. That is tomorrow morning's project. I pulled the plugs and #'s 1 & 4 were not giving any spark. I'm hoping this is because of the timing/points needing adjusting and not a bad coil. Cleaned all the plugs and double checked the gap. They are brand new plugs.

I still have to check the wiring for rusty connections.

I had kremed my tank when I bought the bike because there was a bit of rust in the tank, only to find out later that there was a leak. I had to strip the kreme out with acetone and MEK so that the tank could be welded. The leaks are fixed, but now there is flash rust or surface rust inside the tank. I've got it soaking right now with MEK to get the residual kreme out of the tank, and then I don't know what to do. I bought purple power deruster that I was debating washing the inside of the tank with to get rid of the rust and etch it a bit, wash it out with simple green and then fill it with gas. I've read that kreme isn't all it's cracked up to be, so I'm trying to avoid it but at the same time have a clean tank so I don't get crap all in my carbs that I've spent hours cleaning. Any opinions? I don't want to hook up the tank and try to start it again until I have a clean tank.

I need to take some pictures and start a build thread.

Thanks.

[Achmed]

I'm confused. In your first post you said all the plugs were getting spark. Now you say some are not. What happened to change that?

Also, to answer your questions from a few posts up (since no one else did), you have probably figured out where the carb drain screws are and what they do. The tappet adjustment has to do with the valve clearances. You do it as part of regular tuneup. I doubt that would be a contributing cause to a non-start condition but it is pretty easy to check, even if you haven't done it before. Check the manual for that. There is other advice regarding valve clearances outside the manual, too, but I would start with the manual settings just to get it running.

[anthem78]

I'm confused too. They were all getting a spark as far as I remember. I hadn't done anything different since then and then last night and this morning 1 and 4 weren't getting a spark. I adjusted the gap in the points and now 1 and 4 are getting a spark and 2 & 3 are not. So I have some work to do. I'll adjust the timing too and see if I can get this working.

[Achmed]

Well, you need sparks at all the cylinders! At least to run well. These bikes have been known to run on one or two sometimes. Check the wiring diagram and find the fault that prevents spark from getting to the cylinders. How did you adjust the points gap? I did it wrong once (about two weeks ago) and that was based on bad instructions from I don't remember which manual. Search the forum for points gap adjustment and you will get some help on that.

[Zaipai]

I don't know if this is the same for you. I had a like problem, turns out that I had the wires connected to the points wrong so they were grounding out so all I had to so was make sure the leads where behind the insulator and that fixed the problem. It seem to go between the coils, well turns out that when I adjusted the points I would (with out knowing it) un-short the one set and short the others, drove me crazy till I found it. Just thought I would throw it out there in case. Hope you get it all worked out. I can tell you from exp that these bikes will run on 1 and 4 firing and 2 and 3 not and the other way around. I ran on 2 cyl for a while until I figured out (thanks Hondaman) what was going on..

[anthem78]

Here are some pictures. I checked the gaps and the timing seemed fine. It was my first time doing it, though, so I don't know if I did it right. I used a test light and followed the instructions in the Honda shop manual.

[anthem78]

All four cylinders are getting a spark. Thanks for the help. Now just waiting on the Acetone bath in the tank to finish so I can fill it with gas and see if it fires up. I may take my chances with this deruster (attached pic). Any thoughts?

[Zaipai]

Ignition looks good. Not sure about the deruster. Let me know if you use it and how it turned out. My tank has more rust then a junk yard special and I am looking for an easy way to clean it out.

GL with getting it started, hope it works for you.

[andy8190]

while this thread is up, does anyone know where to get replacement screws for the points plate? or what size they are so i can maybe find some at a local hardware store? And i am referring to the ones that hold the points down

[OldSchool_IsCool]

Take one of the screws with you, the hardware folks should be able to match the length, and thread.  I replaces mine with Allen cap screws.

[anthem78]

I got the bike running tonight and took it on a drive. Thanks for all the help. Now that it's running, I have more questions. After the first start it seemed that only cylinders 1 & 4 fired, because only those two pipes were hot. After other starts the headers from cylinders 2 & 3 were hot, so I don't know if I still have a timing problem.

It also seems to smoke a lot from under the tank, at the top of the engine or out of header #4. It hasn't been run in a few years to my knowledge, so is this normal? I changed the oil, but need to pick up a new oil filter.

Fresh gas. Clean carbs. New plugs. Etc.

It also dies when I ride for a few minutes and then let it idle. After it dies it can be very hard to start back up. After I got back to my house it died in the driveway and I had to charge the battery to get it start again.

How do I know if it's running too rich or too lean? It has stock jets. I'm running pod filters and the stock 4-into-4 exhaust. The only other set of jets I have are 135's which I assumed were too large for this setup.

I'll keep trying to adjust things during the week, but wanted to post my progress.

Thanks.

[Zaipai]

Sounds like maybe a loose wires, maybe in the head light. I am not sure but it sounds like you have some thing flaky going on there. Its usually wires when that stuff happens to me.

[OldSchool_IsCool]

A lot of odd things can happen the first few startups after sitting a while.  There is accumulated dust, debris and oils that need to burn off both internal and external.  Keep at it and don't worry about things unless they persist.

Glad to hear you got 4 hot pipes!  You are on the downslope of the hill now.

Looking at your plugs is the best way to judge fuel mixture.  Black & sooty means rich.  White & powdery is lean.  Tan & dry is just right!

May wana check your charging system.  Hook up a volt meter to your battery.  When not running, the voltage should be about 12v to 12.6v for battery with a healthy charge.  The voltage should rise as the engine is reved.  It should not exceed 14.5 volts.