Author Topic: 76 550K wont fire right on 1-4 video added!!  (Read 14010 times)

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Offline JAG

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #100 on: January 04, 2011, 04:35:00 PM »
I'm sorry TT, after I uploaded those videos I went back and took the carbs back off and found that none of the idle jets were screwed in all the way. I was a little anxious to get it all back together after cleaning on everything for 2 hours that I simply forgot. I put it back together and it's running a lot better. Still rich though.

It makes sense about the float adjustment and it running rich. I'll take them back off tomorrow and readjust them on their sides.
I also found that the main jets don't "seat" as tightly as I would like, so to go a long with your question, they all have o rings in place, but if they weren't sitting in there good (meaning that they are loose) in stands to reason that more gas will be able to come around the jets and make it more rich as well.

So I will definitely address those two situations tomorrow morning and report back to you!!
Can you see light through the slow jet from end to end?

Yes

I'm uncertain about the emulsion tubes...  Are the cross drilled holes clear?

Some of those pictures are fuzzy, but they are definitely clear. I made double sure with compressed air and a wire to poke through each orifice.

Also, the float to pivot brass carrier looks bent.  It should be flat rather than curved.  The height adjustment bend is performed on the tab portion only.

The floats were all a little lop sided when I got the bike. I straighten(Leveled) them out the best I could so they would have the same movement through travel. To help I have been measured (although incorrectly) both sides of the float to make sure that 22mm mark was the same on both sides.
Are you using new orings on the main jet?
Are you using ANY orings on the main jet?
Yes they do have o rings, but they are pretty loose in the bore and will require replacing. I noticed that today. From me taking them off and on so many times I am sure that they have worn out.
You also need to "prove" the air jet passages.  Since you have pressurized carb cleaner place the nozzle/tube into the air jet orifice and "prove" the fluid reaches:
A: the slow jet emulsion tube chamber, from the slow air jet.
B: the main jet emulsion tube chamber, from the main air jet.

I did this today and actually the pressurized carb cleaner came out that jet from where the choke valves are and squirted me directly in the eye. It definitely had great pressure, cause it shot up about 2 feet.. Washed my eye out immediately and dawned a pair of safety glasses for the remainder of my carb journey.

I will source those o rings tomorrow as well as adjusting the float height correctly. While its all apart I'll go through the jet orifices once again and make doubly sure all air/gas ways are clear. Put it back together. Fire it up and sync the carbs after a proper warm up and report my findings.


Woohoo. I love progress!
Cafe Racing is mainly a matter of taste. It is an atavistic mentality, a peculiar mix of low style, high speed, pure dumbness, and overweening commitment to the Cafe Life and all its dangerous pleasures. I am a Cafe Racer myself, on some days - and it is one of my finest addictions. ~H. S. Thompson~

Offline TwoTired

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #101 on: January 04, 2011, 05:06:00 PM »
I'm still unclear if you have removed and cleaned the mains emulsion tubes.  See:
http://forums.sohc4.net/index.php?topic=60224.msg655868#msg655868

The bottom picture shows a dirty one.  And many people don't even know it is inside the carb body under the main jet.
The top picture shows a clean one amongst the other parts.

If those holes are plugged, the bike will run rich.

For much the same reason one doesn't look down the barrel of a gun, one also should not look into holes of a pressurized carburetor.
I hope your eye heals.
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline JAG

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #102 on: January 04, 2011, 05:22:02 PM »
I'm still unclear if you have removed and cleaned the mains emulsion tubes.  See:
http://forums.sohc4.net/index.php?topic=60224.msg655868#msg655868

The bottom picture shows a dirty one.  And many people don't even know it is inside the carb body under the main jet.
The top picture shows a clean one amongst the other parts.

If those holes are plugged, the bike will run rich.

For much the same reason one doesn't look down the barrel of a gun, one also should not look into holes of a pressurized carburetor.
I hope your eye heals.

Ah I see TT. And no, I haven't removed those yet.. I have seen them down there underneath the main jets, but I have no idea how to get them out. I didn't see a slot for a flathead screwdriver to fit or anything. From the look of that picture it doesn't seem to have any threads, so it must be pressed it? How do I tackle this?

Nevermind, I found a post of yours explaining how.  :D haha  ;)

"The main jet is at the bottom and pulls straight out.  There is an o ring on the jet. If hardened, it is difficult to remove.  And, if it is hardened it will never seal again unless replaced.
The needle jet is above that and part of the emulsion tube.  The whole tube comes out the bottom where the main jet sits.  It is usually pressed out from the carb bore side after the slides are removed.

Cheers,"

Since it is removed after the slide is out, while I am in there on that side again I will put the slide needle back to the 4th notch from the top instead of the 3rd.

Cafe Racing is mainly a matter of taste. It is an atavistic mentality, a peculiar mix of low style, high speed, pure dumbness, and overweening commitment to the Cafe Life and all its dangerous pleasures. I am a Cafe Racer myself, on some days - and it is one of my finest addictions. ~H. S. Thompson~

Offline JAG

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #103 on: January 04, 2011, 05:26:54 PM »
.....Looks like you would get 'tired' of repeating yourself over and over again TwoTired.  :D

But I do appreciate you and everyone else help on this board. Its been a blessing for me.  ;)
Cafe Racing is mainly a matter of taste. It is an atavistic mentality, a peculiar mix of low style, high speed, pure dumbness, and overweening commitment to the Cafe Life and all its dangerous pleasures. I am a Cafe Racer myself, on some days - and it is one of my finest addictions. ~H. S. Thompson~

Offline JAG

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #104 on: January 05, 2011, 08:55:30 AM »
I got the o rings and took the emulsion tubes out. They were dirty but it wasn't clogged. Neither was the drilled holes. So I cleaned everything again with q tips and carbuerator cleaner.

I also made sure air could get through the AMS to the slow jet and from the inlet inside the venturi tube back out the AMS inlet. And the brass tube near the choke valves out the main jet. All is clear.

I'm trying to bench sync it again  and now the #1 slide doesn't travel very far. from closed to the 1/16 clearance I need. But I can continue to screw it in and it won't raise much higher than that. Gotta run a search to see how to fix it.

Also adjusted float heights with carbuerator bodies on there side. Looks like it was way off from my previous measurements, and in fact required even More gas to achieve that 22mm distance via the float tong/prong, or whatever you wanna call it.
Cafe Racing is mainly a matter of taste. It is an atavistic mentality, a peculiar mix of low style, high speed, pure dumbness, and overweening commitment to the Cafe Life and all its dangerous pleasures. I am a Cafe Racer myself, on some days - and it is one of my finest addictions. ~H. S. Thompson~

Offline TwoTired

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #105 on: January 05, 2011, 11:02:24 AM »
I'm trying to bench sync it again  and now the #1 slide doesn't travel very far. from closed to the 1/16 clearance I need. But I can continue to screw it in and it won't raise much higher than that. Gotta run a search to see how to fix it.

Precisely why I hold the drill bit method in disdain.

Back out the main idle adjust knob a few turns and see if you can fully close all the slides.  If you can't, then all the slide adjusters are biased too much toward the open position.
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline JAG

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #106 on: January 05, 2011, 11:23:30 AM »
Yeah I thought the idle screw was turned in, but I turned it out all the way where it almost fell out of the holder and it didn't change at all.  They (the slides) can all fully close however when I try to open it back up the with slide adjuster screw it doesn't want to open up as far as the other ones do. For instance the number 2 slide will adjust and open up almost half way up the venturi tube before the adjustment stops. The number 1 slide will only open up with the adjuster screw maybe 1/8". After that it just stops. I have to take them all back apart anyways to put the needle height back to factory height so maybe something will break free when I put it back together. I know all the springs and such are in place, must be something I'm missing.
Cafe Racing is mainly a matter of taste. It is an atavistic mentality, a peculiar mix of low style, high speed, pure dumbness, and overweening commitment to the Cafe Life and all its dangerous pleasures. I am a Cafe Racer myself, on some days - and it is one of my finest addictions. ~H. S. Thompson~

Offline Spanner 1

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #107 on: January 05, 2011, 10:11:45 PM »
Jag, you started this thread on Dec. 11 th. looking for help( 5 pages and 107 posts ). It is now Jan 5th. You have had many , many replies from members particularily TT. You said you set all the carb. settings to spec. and now 3 wks. later you casually ( today) mention that your float levels were ' way off' when you finally decided to set them by the correct method.... that's really unfair to folks trying to help IMO. Hope the correct float levels solve the problem.  :)
« Last Edit: January 05, 2011, 10:13:52 PM by Spanner 1 »
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Offline scottly

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #108 on: January 05, 2011, 10:55:06 PM »
For the last time, if you want to know what the fuel levels in your bowls are, use the clear tube method. More accurate than a rule or any gauge, IMHO.
Don't fix it if it ain't broke!
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Offline JAG

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #109 on: January 06, 2011, 08:53:56 AM »
Well all is fixed in terms of richness. There is no more black smoke out of the exhaust. And in doesn't wreak of gas in the garage. However the spark plugs condition show chalk black soot on 3 of them and #2 was slightly wet. I assume a true reading cannot be reached on the spark plugs without doing a plug chop.

The condition now is smoke flowing out of #2 & #4 exhaust. It looks to me as being white however my dad believes its actually blue.

The condition doesn't change when revved to 3-4K rpms either. The white or blue smoke isn't as apparent but there is still smoke there. Is this telling me that some of piston rings are broke or stuck and need replacing? Anything else I should look at?

Thanks a bunch.
Cafe Racing is mainly a matter of taste. It is an atavistic mentality, a peculiar mix of low style, high speed, pure dumbness, and overweening commitment to the Cafe Life and all its dangerous pleasures. I am a Cafe Racer myself, on some days - and it is one of my finest addictions. ~H. S. Thompson~

Offline JAG

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #110 on: January 06, 2011, 09:08:09 AM »
I was rechecking the tappet clearances and stuck a screw driver down #1 spark plug hole to check for TDC and it actually sunk down on top of the piston and pulled out about 32nd to a 1/16 of soot build up on the top o 8)f the piston. Seems like a lot to me. :o???
Cafe Racing is mainly a matter of taste. It is an atavistic mentality, a peculiar mix of low style, high speed, pure dumbness, and overweening commitment to the Cafe Life and all its dangerous pleasures. I am a Cafe Racer myself, on some days - and it is one of my finest addictions. ~H. S. Thompson~

Offline Mark M

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #111 on: January 06, 2011, 09:14:19 AM »
 ::) ::) ::)
In the UK anything over 40 years old only needs insurance and Fuel.

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #112 on: January 06, 2011, 10:05:26 AM »

I'm trying to bench sync it again  and now the #1 slide doesn't travel very far. from closed to the 1/16 clearance I need. But I can continue to screw it in and it won't raise much higher than that. Gotta run a search to see how to fix it.

[/quote]


 Any solution for this yet? Also, as mentioned,the clear tube method for checking the fuel level in the bowls will tell ya a lot. The level of fuel should be about 2-3 mm. from the top of each bowl, and STAY at that level
once the float moves up and closes the valve. If that condition is not met at rest, fuel delivery amount won't be right when its running
either. I've seen on my own bike where, the needle valves were allowing too high a fuel level in the bowls even AFTER gauging/adjusting the floats to spec., enough to make the thing flood and not start.
Fuel levels can also affect emulsion tube circuit operation in a negative way if they aren't PHYSICALLY CORRECT.
If I'm incorrect, someone please correct me. Recheck your oil level and see if its too high again just to be safe too. IMHO...just sharing a thought.
« Last Edit: January 06, 2011, 10:20:25 AM by DH »

Offline JAG

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #113 on: January 06, 2011, 10:39:17 AM »
I did fix the #1 slide.

The oil smelled like gas again so I drained it and put new oil and filter in. I had increased but no where near as bad as it was when I first changed it.

I drove it around a couple miles. Did a plug chop and all the plugs were still covered in soot.

Here's the tube method.2-3 seems to be too high to me. Maybe its all of them. I dunno. They are in order from 1 to 4 
Cafe Racing is mainly a matter of taste. It is an atavistic mentality, a peculiar mix of low style, high speed, pure dumbness, and overweening commitment to the Cafe Life and all its dangerous pleasures. I am a Cafe Racer myself, on some days - and it is one of my finest addictions. ~H. S. Thompson~

Offline Duanob

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #114 on: January 06, 2011, 10:49:32 AM »
I would say when you get it all running again pour a high mix of Seafoam in the gas tank and run it hard, really hard. Hopefully that will burn some of the carbon build up and gunk out of the cylinders.
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Offline TwoTired

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #115 on: January 06, 2011, 11:00:36 AM »
If all the floats are set the same, why aren't fuel levels identical across the bank?  
Given your complaints, I'd shoot for - "same as #4".

What setting are you using for the Air Bleed Screw?

Getting rid of the chamber soot needs high combustion temps.  A leisure stroll around the block just won't do it.
Engine has to be fully hot and flogged to raise the temps.  Use hotter heat range plugs if necessary.  If you are getting misfires, new, clean, plugs may be required.  Open pipes hurt heat retention.

Air cleaner status is...?

Please explain your understanding of a "plug chop".

Are all the spark plugs now showing the same deposit pattern?

If the engine hasn't run for a while, ignore the blue smoke until you get the mixture correct, and put 100 miles on the engine.  Sometimes the running bits need to re-seat.


Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline JAG

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #116 on: January 06, 2011, 11:11:12 AM »
I would say when you get it all running again pour a high mix of Seafoam in the gas tank and run it hard, really hard. Hopefully that will burn some of the carbon build up and gunk out of the cylinders.

That's what I'm thinking bud.
These bikes run better the more your ride them, and I know this thing has been sitting for years, with gas in the bowls and I don't know what all else, virtually untouched..


If all the floats are set the same, why aren't fuel levels identical across the bank? 
Given your complaints, I'd shoot for - "same as #4".

I'll try that now.
What setting are you using for the Air Bleed Screw?

1 full turn out

Getting rid of the chamber soot needs high combustion temps.  A leisure stroll around the block just won't do it.
Engine has to be fully hot and flogged to raise the temps.  Use hotter heat range plugs if necessary.  If you are getting misfires, new, clean, plugs may be required.  Open pipes hurt heat retention.

I agree with you, this thing is going to have to been driven a bit to see how it is really going to run.

Air cleaner status is...?
Still trying to find some decent (used) boots to go in the box I already. The ones in it now are as hard as a rock.


Please explain your understanding of a "plug chop".

Get engine running at normal operating temperatures. Find some place to get up some speed, (45-50mph) (4-5K rpms) pull in clutch, turn kill switch. Check plugs to see what they read.


Are all the spark plugs now showing the same deposit pattern?

They were still covered in black soot after that plug chop. I'll reduce gas levels to the same as what #4 is showing and try it again with new plugs.
Cafe Racing is mainly a matter of taste. It is an atavistic mentality, a peculiar mix of low style, high speed, pure dumbness, and overweening commitment to the Cafe Life and all its dangerous pleasures. I am a Cafe Racer myself, on some days - and it is one of my finest addictions. ~H. S. Thompson~

Offline TwoTired

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Re: 76 550K wont fire right on 1-4 video added!!
« Reply #117 on: January 06, 2011, 11:40:30 AM »
What setting are you using for the Air Bleed Screw?

1 full turn out
Try another 1/4 to 1/2 a turn.

Please explain your understanding of a "plug chop".

Get engine running at normal operating temperatures. Find some place to get up some speed, (45-50mph) (4-5K rpms) pull in clutch, turn kill switch. Check plugs to see what they read.

There are three metering devices in the carbs that activate at different throttle positions.  The circuit you are using as described above is only the slide needle mixture.  Further, operating at all throttle positions reflects accumulated deposits from each of the positions.
A plug chop is done with only one throttle position, and begins with new or squeaky clean spark plugs operated 90+% at only one throttle setting.  The carb dial in process usually begins Wide Open Throttle (WOT) on a test track using the bike a rider loads to provide a load resistance to the engine.  This is how to determine the main main jet size.  Then chops are made with 3/4 throttle position, 1/2 position, 1/4 position to find the slide needle height, and taper.  Finally, for these Cb550 carbs, the Air screw is adjusted for throttle response at up to 1/2 total throttle travel change.

Note, the air filter and exhaust parameters will effect the carb settings during the above process.  So, the bike should be in its final configuration beforehand. 


Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.