Topic: 76 550four idling problems

[JAG]

A buddy of mine sent his bike to me to have it worked on. When we picked it up it wouldnt even run, and I found it was due to the starter switch's wiring that caused the issue..

After fiddling with the carbuerators and trying to get them to stop overflowing ( which I still haven't been able to get it to stop out of the third carb ) I finally got it to run for about five minutes.

The problem I am having is the idling (when not touching the idle screw or throttle) will increase to about 3K rpms, and lower itself back down to around 1600 rpms. During the five minute period where I had it running it did it on it's own several times and I dont have the slightest clue why it would do that.

When revving the engine black sut is flying out the exhaust, which in fact got all over my pant leg. When the engine shuts off, there is some smoke coming out of two of the exhaust. And some came out of the #1 carb at one point after it shut off.

Something else I dont understand is these butterfly-like clips that go underneath the floats that twist on. Why in the world are they on there? Because I have never seen it on a 750.

Again this is a 76 550. There is no airbox/carbs are open, and the exhaust is 4 individual exhausts coming from each cylinder, and they stop right underneath the seat.

Any thoughts guys would be greatly appreciated. I have no experience with these 550's..

Thanks

[OldSchool_IsCool]

A whole lot going on here!  The soot suggest you are running rich.  But the lack of intake filter(s) would make things lean.  Maybe there is some jet changes and/or idle screw changes that have over compensated for the lack of filters.  The idle climb/fall is a symptom of the carbs being out of sync.

Suggest you do a complete 3K tune up (valve adjust, cam chain adjust, timing, etc) then see how she runs.  A carb cleaning and bench sync are also likely in your near future!

[JAG]

Thanks for the quick response..

I forgot to mention the first thing I did when he brought it home was too clean the carbs and the bench sync and put new spark plugs in it..

I dont know how much different this 76 550 is from my 74 750K as far as timing/valve/cam chain adjustment..

Looks like I need to go find me a 550 manual.

I thought that maybe the soot was from it sitting for so long without being ran. I know when when we first picked it up I could only get it to run off of one cylinder. After closer inspection, I noticed the spark plugs were getting drenched with gasoline and not allowing the plug to fire. So I back off of all the floats and tried to allow it to receive less gas. Once I achieved that, I can get it to run off of all 4 cylinders. Yay..

The bike came with an airbox, but doesn't have any boots to go from the carbs to the box, so I just took it out for the time being.

I know the exhaust that is on there is maybe an inch in diameter, which creates a nasty sound when its running.. (Way too loud!!!)

But as far as trying to get it just to run smoothly, I suppose I need to go have a look at the timing and valves, once all that is clear and looking good, I'll go for the carb sync?....

Does the carb sync tool that I have for the 750, will it work for the 550 carbs??

[flybox1]

The butterfly-like twist on clips are there to hold the main jets in place.
sort thru the carbs again ensuring float levels are correct(especially #3), everything is cleaned, and do a bench synch of the slides.
you could also pull the main and idle jets and look at the # stamped on the side to see what is in there.
you'll want to know if your buddy is going with a stock airbox or pods, and jet appropriately.

As oldschool stated, do the 3k tuneup, and then the carb sync. 
dont know what type of sync tool you have, so i cant answer that. 
morgan carbtune works fine.

[fletcha221]

I dealt with the same problem. It sounds like your carbs are out of sync, as in the slides are closing too far at idle. However, this makes for an easy start, and the bike will come alive, and run the rpms up a little. When the bike warms up, the rpms drop down (and in my case, the bike bogged out). When I would get it running, I would rev the motor and black smoke would shoot out of the exhaust, your carbs are running way way rich. Take a 1/8th inch drill bit and adjust the slides down to where you can just put the drill bit in and out at idle (on the airbox side of the carbs, this is important, make sure you sync'ed the correct side).

The butterfly clips hold the main jet into the essembly.

[JAG]

The Vacuum sync gauge I got, I purchased from z1 enterprises, I tried to find an illustration of it, but it seems they dont carry that same one anymore. It's not so much the sync gauge I have it's how I am supposed to go about doing it. On the 750 there are "plugs" which you unscrew and then screw the pipes that attach to the hoses that go into the vacuum gauge. I dont see that on this set of carbs.

I went ahead and bench synced the carbs again, and they were, as suggested way out.. I don't know what I was smoking when I did it. But they are now all set exactly the same using a 1/8" drill bit. I did not think to look at the jet size when I had them off, I'll have to take them back off to look at it again.

The points was way off.. If it's supposed to be set anywhere from .012-.016 these had to be set at around .019.. So I promptly set them to .014. The timing was almost dead on.

Air screws are set to 1 full turn out.

Buttoned it back up and it still did the same thing as the idling is concerned.. However no more leaks, and no more soot.. It seems to me like it may not be getting enough gas. It'll start to warm up idling around 2K rpms. It'll then shoot up to 3K rpms and then plummet and try to die.. When I was doing this with my 750, everything was set except for the carb sync, and the bike just trembled all over, and the handle bars vibrated like crazy.

I'm not sure how I am going to be able to sync the carbs if I can't even get it to idle normally or atleast stay consist.

[JAG]

after it died, I started it back up and then it only ran on two cylinders (3 and 4)

The gas tank is getting low, so I am going to get some more gas, and see if it helps to get it run on all four cylinders and maybe I can get it to run long enough that it will finally warm up and I can finally see how it will idle..

I know with a cold start the idling is going to be somewhat irregular, but this is extreme..

[OldSchool_IsCool]

Try spraying some carb cleaner or WD-40 on the boots between the carbs and the head next time you have 'er running and sitting at a somewhat consistent RPM.  If the RPM changes when sprayed, then there is a leak in that carb boot.

A sync tool that works on a 750 will work on a 550.

Search the site for "flashlight sync method" and try that the next time you bench sync. 

[SHELLFISH]

Sounds to me like your carbs are really messed up.
I'm in the process of rebuilding mine right now.
I found two plugged main jets (varnish) and one plugged slow jet (foreign object).
Interesting that #2 and #3 were my problem cylinders also.

[Stev-o]

Another thing you may want to check is spark. On my '76 550F one spark plug cap was bad and cylinder #1 was not firing. I put NGK aftermarket caps on [$4ea] as OEM's are not available.
Now I need to sort my carbs too.

Good Luck.

-Steve

[Yoshi823]

Try spraying some carb cleaner or WD-40 on the boots between the carbs and the head next time you have 'er running and sitting at a somewhat consistent RPM.  If the RPM changes when sprayed, then there is a leak in that carb boot.

A sync tool that works on a 750 will work on a 550.

Search the site for "flashlight sync method" and try that the next time you bench sync. 

If the revs do pick up but the inlet rubbers are known to be good the I would suspect the 'O' rings that go between the inlet manifolds & the head. I have had a problem with these on several 500/550 fours, the rings had gone hard, cracked & even had one split. I have always put new 'O' rings back in place & sealed with Hylomar. It always made a differance to the running of the engine, & made balencing the carbs a doddle.

[JAG]

Try spraying some carb cleaner or WD-40 on the boots between the carbs and the head next time you have 'er running and sitting at a somewhat consistent RPM.  If the RPM changes when sprayed, then there is a leak in that carb boot.

A sync tool that works on a 750 will work on a 550.

Search the site for "flashlight sync method" and try that the next time you bench sync. 

If the revs do pick up but the inlet rubbers are known to be good the I would suspect the 'O' rings that go between the inlet manifolds & the head. I have had a problem with these on several 500/550 fours, the rings had gone hard, cracked & even had one split. I have always put new 'O' rings back in place & sealed with Hylomar. It always made a differance to the running of the engine, & made balencing the carbs a doddle.

Alrighty Ill go check the boots and report back, is there a diagram/illustration of these 'O' Rings anywhwhere?

Also Ill probably go ahead and take the carbs back off so I can tell you guys the size of these jets..  Be back shortly!!

[fastbroshi]

It always made a differance to the running of the engine, & made balencing the carbs a doddle.

Is that like a poodle?  

To answer your question about the O rings, they fit in a channel in the face of each intake manifold tube where they contact the cylinder head.

[Deltarider]

Jag, it's part 38 in:
http://www.cmsnl.com/honda-cb550k2-four-usa_model464/partslist/E++01.html

[JAG]

I dont know what the heck Im doing wrong.. The gas is either flooding out of the carb or there is not enough going into it. I cant seem to get them just right. It goes from running off of all four cylinders to just 3 and 4. Then it goes to just 2 and 4. Then it just goes to number 4. When it seems to have too much gas it fouls out the plugs and therefore generates no spark. All the sparkplugs definitely aren't where they should be, all seem to be wet with gasoline no matter how I set the floats..

The slides are definitely bench symc correctly, any lower and I'd be getting nothing through there.

Sometimes I get spark i.e. ground the spark plug to the exhaust hanger/flange, sometimes I dont. I don't know if my ground is good or not, but Ive never had a problem doing this method before now. I got an extra set of coils I think I'm going to put up there. There was a way to check the coils with a multimeter but I dont remember how I did it. It's been so long..

The next step is the guy is going to purchase a float tool so I can better set them all correctly

This has been very disheartening..

The O rings I wouldnt think would be a problem. But I still havent taken that portion off the intake yet to inspect it, Im still trying to get the f'er started, and running off of all the cylinders again.

I checked to see if the boots had any leaks via the wd-40 and there was none to be found. They are seemingly new; very pliable and soft rubber.

On the number 4 exhaust there is quite a bit of "pop pop pop" coming from it. To hold your hand down there its almost like it will blow your hand back but its not indicative of the other cylinders/exhaust.


Sigh... I havent given up yet..  Thanks for all the insight and suggestions.

[JAG]

oh and the main jet is 100, and the slow jet looked to have K38 on it.

[JAG]

Okay I'm starting with the coils.. I could never get a spark. I hooked the multimeter to each of the wires- Black/white stripe and blue wire got like 6 ohms. Same to the Black/white and yellow wires and got the same ohms.

Tried laying sparkplug across exhaust flange like I always do and cycled the engine with start button. Nothing.

Tried laying across flange and played with the points. Cycled engine with the wrench- Nothing.

Only thing I'm getting is a clicking when I manual raise point from the coil. And I also receive spark from point but not the plug.

Checked if there was power getting there from the battery via test light and accidentally touched both Black/White striped wires cause they are coupled together and it blew a fuse So I know power is getting to it.

How do I check if power is getting from the coil Down to the sparkplug/boot?

Any other suggestions?
Lamens terms please this is my first rodeo!

Thanks.

[OldSchool_IsCool]

Connect your volt meter to ground and to the blue wire at the points. Your
meter should jump from 0 to 12v as you rotate the engine. If not, disconnect the green condenser wire and try again. Still no 12v jump? Trace the blue wire to the coil inspecting all connectors.

Repeat with yellow wire.

If blue & yellow wires check out, pull the plug caps off the plug wire and clean the insides. May need to snip a quarter inch off the wire to get to clean copper.

Check also for wire to head arcing by turning off the lights in your garage.

[Deltarider]

I would unscrew caps from the coils HT leads and then whilst turning the engine check for spark by holding ends of lead within 5 mm of head. If spark is there cap is shot.

[JAG]

I don't know what. HT leads means or what 5mm head is..

I would unscrew caps from the coils HT leads and then whilst turning the engine check for spark by holding ends of lead within 5 mm of head. If spark is there cap is shot.

What do I set the multimeter to? Its got 7 different functions

[OldSchool_IsCool]

HT= High Tension. In the case of coils, it means the plug wires. 5mm is about an eighth of an inch. Hold the wire that close to the engine block.

If you want to measure 12v, set ur meter to prolly 20v DC. 

[Deltarider]

I don't know what. HT leads means or what 5mm head is..
Quote from: Deltarider on Today at 04:22:42 pm
I would unscrew caps from the coils HT leads and then whilst turning the engine check for spark by holding ends of lead within 5 mm of head. If spark is there cap is shot.


What do I set the multimeter to? Its got 7 different functions

O.K. HT leads are the two black thick high tension wires that end in the sparkplugcap that sits on top of the spark plug that is screwed in the head of the engine.
After pulling these caps from the sparkplugs, you can unscrew the caps from their wires. Now you could check you coils - provided they are original - for continuity by putting the DMM's probes in the wires. Select 20KOhm. Your DMM should read 14 -15 Kohms. But you can also bring the leads within say 5mm distance of the engine or frame. With your killswitch in the runposition (important!) and the ignitionkey switched on (equally important!) a spark should fly between the lead and the engine (or frame) when engine is turned.

[JAG]

Okay tried the wire to the coil and didn't receive reading guess I'm doing it wrong. However I took all caps off and did the 5mm thing and receive blue spark from each.

Is it possible to check continuity with just the boots? Cause I'm getting about 14 ohms from them and only getting 8ohms from one when I test it.

With the point wires I get .04 from the closed one and 9v from the open one and with turning over the engine I get round 16volts?

[JAG]

More so with the spark plug caps/boots.. If I am getting a beautiful blue spark from just the wires without the caps/boots on there then that should lead to the boots being faulty right??

Cause having the boot on there, spark plug snapped in place, and grounded across metal, I get no spark from the spark plug. The spark plugs are brand new, other than having some gasoline dampening them up from over excessive float height they should be okay..


Thanks so much for the help guys, just seeing some spark from the spark plug wires feels pretty damn good, and a point in the right direction.

[Yoshi823]

Resistive NGK plug caps should measure about 5000-10,000 ohms. There is a resistive element inside of the cap that can go open circuit & delay/stop the spark energy from the coil getting to the spark plug. I've come across this several times on my dirt bikes, so have removed the resistor (looks like a fuse) & put in place a suitable length of brazing rod that I had lying around.
http://www.ngksparkplugs.com/docs/Resistor_Covers.pdf