Author Topic: 1977 CB550K running issues - seeking help (Read 4097 times)

Can550 · « **on:** September 02, 2017, 08:30:29 PM »

Hi guys
I have had tremendous help on my other projects in the past so here I'm again with some older repeating issues and some new (to me) and seek your help.

I recently acquired a 1977 cb550k and seller rode it behind me to my house. I then took a small round and it ran strong.

Next morning I was unable to pull the choke (stuck) and it did not start. I then cleaned tons of gunk and lubed the choke cable, it fired up right away but ran terrible. Vibration, misfiring, popping and rough idle. Surprised what happened overnight

I then started to investigate and found boot clamps were rather loose, tightened those but not huge difference

I removed carbs, cleaned them well (they looked clean and recently built). One of the mixture screw O ring (tiny thing) looks like it was pinched so it does not seat properly (I'm assuming looking at its shape).

However put the carbs back on and it started with choke, release the choke and it died right away. Didn't accept any acceleration without choke, lot of hesitation and died very quickly. Tried to sync carbs but bars on sync tool stay at bottom and show no movement (my carb tool is fine).

Removed carbs again, looked inside, seemed fine. Now I will put them back on once I have some direction to fix.

Oh by the way it's all stock. Valves and timing adjusted, battery newish and fully charged, fresh gas, fresh oil and filter. Spark plugs are D7EA, caps are 5k ohms. Stock pipes, stock jets 90 air filter newish. Only missing bits are tube from filter box and tube from Air plenum/ box. Would it make any difference ?

When ran with choke, popped everywhere, pipes, carbs.

Appreciate direction to have it running for remainder riding days

Cheers

Sent from my iPhone using Tapatalk

Jamus · « **Reply #1 on:** September 03, 2017, 05:50:43 AM »

Did you remove and clean the pilot jets? They are pressed in, and can be removed with vise grips and a small piece of leather to protect the brass jet. Soak in acetone while you clean the pilot circuit passages. Clean the pilot jets with a guitar strings. BTW, the manual supplement says the factory pilot jets are#38, but most people find #42 in theirs.

Can550 · « **Reply #2 on:** September 03, 2017, 07:36:11 AM »

Yes
I removed and cleaned #42 jets
Sprayed carb cleaner through passages. Cleaned jets with guitar string and thine copper wire strand.

Do I need to fish wire strand through passages ?

Sent from my iPhone using Tapatalk

Can550 · « **Reply #3 on:** September 03, 2017, 10:19:48 AM »

Put the carbs back after thorough cleaning of each part. Luckily overflow leak from carb 4 is no longer there.

Everything else is same. Starts right up with choke.

Doesn't take any throttle.

RPMs go up itself then dies.

Mixture screw tried at 1, 1.5, 2 turns out.

Exhaust 3,4 blowing hot air, 2 warm and 1 cold.

Frustrating to see that Carbtune bars don't even move except with choke.

Help pls.

Sent from my iPhone using Tapatalk

jgger · « **Reply #4 on:** September 03, 2017, 11:15:03 AM »

I'm not a carb expert, but I did stay at a Holiday Inn once...... If it only runs with the choke on that would make me think there is a huge air leak somewhere. Are the carbs seated good with no folds in the boots? Are the boots intact, no cracks or tears?

Can550 · « **Reply #5 on:** September 03, 2017, 01:31:49 PM »

Thanks everyone
It's boots between carbs and engine that are hard like rock and have crack traces where clamps sit

Sent from my iPhone using Tapatalk

jgger · « **Reply #6 on:** September 03, 2017, 01:58:48 PM »

I hope that does it for you, it's ALWAYS the stupid stuff that bites me in the butt! Good luck.

Can550 · « **Reply #7 on:** September 03, 2017, 03:34:41 PM »

It was not cold as not firing cold. It was blowing colder air compared to 3&4

Unless if 1 is not firing but will still blow air

Sent from my iPhone using Tapatalk

Can550 · « **Reply #8 on:** September 04, 2017, 11:38:15 AM »

Thanks calj737
I shall check spark on #1 and contact at plug cover/ wire. I wish I could cut 1/4" end but it's already sitting at the edge. I removed cap and can see poor connectivity.

Is a spliced and wire extension recommended?

Sent from my iPhone using Tapatalk

Can550 · « **Reply #9 on:** September 04, 2017, 02:06:16 PM »

Today everything is closed so couldn't get to buy parts and work on bike.

Measured apart plug caps (they are all 5k ohms) 1,2,4 measured between 4.79-5 k #3 is ZERO no resistance

Tomorrow will buy one but meantime excuse me being naive, what can this cause ?

Sent from my iPhone using Tapatalk

Can550 · « **Reply #10 on:** September 04, 2017, 02:16:54 PM »

I did clear tube test and level sits about 2mm below bowl gasket.

My manual says to use DR7EA plugs D7EA for American bikes so guess 5k ohms caps are stock

Sent from my iPhone using Tapatalk

Can550 · « **Reply #11 on:** September 04, 2017, 03:39:09 PM »

Well plugs aren't the right picture now (a bit blackish) since bike was running on and off with insulators leaking, wrong timing etc.

If I didn't find new insulators tomorrow, considering to shrink wrap them what is the opinion on that if anyone has done before.

At the moment bike has D7EA but considering to buy a set of DR7EA since covers are 5k

Sent from my iPhone using Tapatalk

Can550 · « **Reply #12 on:** September 05, 2017, 05:04:47 PM »

Just two days ago all slides were moving with throttle perfectly (carbs were cleaned and rebuilt) today put new plugs and insulators and #4 slide isn't moving at all. Stuck at the bottom. What should I check. Removed the top covers and I can see all remaining three have two arms that move with throttle, only one moves in #4 whereas the one with spring that is to lift slide, doesn't move rather prevents movement of others. Removed the screw from this one and remaining three moved freely.

Hope didn't damage anything while man handling install and don't have to remove carbs again

Sent from my iPhone using Tapatalk

Can550 · « **Reply #13 on:** September 05, 2017, 09:15:55 PM »

Cannot forgive myself
Damaged #4 carb body. Pinched cylinder and slider is stuck.

Not sure if I can use body from an other CB or have to source only 550
Appreciate any help/ suggestion.

Sent from my iPhone using Tapatalk

Can550 · « **Reply #14 on:** September 06, 2017, 07:11:19 AM »

Sent from my iPhone using Tapatalk

754 · « **Reply #15 on:** September 06, 2017, 08:46:02 AM »

If you can get the slide up, pushing from underneath....very carefully you can fix it... I think.
You will see a shiny spot where it is binding. Work that down carefully. 400 grit paper around a 1/2 rod would probably work. Worth a try, might take an hour, but gets your carbs working again.

Can550 · « **Reply #16 on:** September 06, 2017, 11:37:33 AM »

Yes
When I'm putting needle clip on 3rd groove, is it 3rd from top or bottom?
Thanks

Sent from my iPhone using Tapatalk

Can550 · « **Reply #17 on:** September 06, 2017, 07:07:23 PM »

Quote from: calj737 on September 06, 2017, 01:40:58 PM

Shouldn't matter as I believe there's only 5. You choose.

Ha ha so silly of me
Counted twice and 6 both times but you are right actually 5

Previous setting was 2nd from top, wonder why

Sent from my iPhone using Tapatalk

Can550 · « **Reply #18 on:** September 06, 2017, 07:51:57 PM »

Thanks calj
I already moved all to 3rd groove including the #2 (reference carb). Would it be running rich now (if ran at all). Do I still keep mixture screw at 2 turns out ?

Sent from my iPhone using Tapatalk

Can550 · « **Reply #19 on:** September 09, 2017, 07:56:11 PM »

Oil pool behind sprocket cover. Tons of oil came out when removed the cover.

It shows traces of oil coming through starter motor where it goes inside the crank case. O ring was hard and flattened, replaced with a new one. Tomorrow shall investigate further if it was starter motor O ring or some other oil seal.

Following are photos I took right after removing the cover if there are any indicators, would appreciate

Sent from my iPhone using Tapatalk

Can550 · « **Reply #20 on:** September 13, 2017, 08:37:48 PM »

Changed one 47mm and two 14mm O rings and major leak stopped. A relatively smaller leak is still present on top of oil pressure switch where connector is held with a screw.

Guess will have to replace the switch. Called up Honda (2 locations) neither had. Is there any other switch that could be used? I remember reading somewhere on the forums a member used or suggested to use from Acura

I can only start and run it to see how it idles once leak is addressed otherwise mess on garage floor (which has been cleaned twice before, same bike same reason)

Sent from my iPhone using Tapatalk

Can550 · « **Reply #21 on:** September 23, 2017, 09:18:59 AM »

Replaced the oil pressure switch (K&L) things seem fine. Cranked few times till the oil light went off and didn’t notice any oil leaks. Next is to fix carbs and run it to see

I don’t get my carb sync gauges to move at all when connected with bike unless I rev it ??

Sent from my iPhone using Tapatalk

Can550 · « **Reply #22 on:** September 27, 2017, 06:12:00 PM »

Bad news, carb #4 body is damaged along with slider. Looked/ searched everywhere including forums but no luck. Was talking to couple of guys who had come to buy a 1976 cb550k tank from me and one of them went to his car and gave me a bag full of various carb parts which included carb 4 body

and a very clean looking slide. Have removed carbs and waiting to get bowl gaskets then will replace body and put on the bike. Shall report back once get it to running.

Sent from my iPhone using Tapatalk

Can550 · « **Reply #23 on:** September 30, 2017, 04:27:56 PM »

So put the carbs back on the bike and no improvement at all.

Fires right up with choke. Release the choke, dies

Little warm and tries to idle then all of sudden surges to 3000+ RPM, adjust the idle screw drop RPM to 1100, sits there for seconds and struggles to run. Blip the throttle, Rpm go to 2500-3000 but then wouldn’t come back. Open up idle screw then not enough to idle so dies.

Sprayed wd40 on intake boots and manifold but made no difference.

Carbs have been cleaned few times and clean for sure. (Pulled all brass parts )..

It’s frustrating don’t know which direction to go. Seek help

Timing is a hair retard on both sets (1-4/2-3).
Tappets adjusted
New oil and filter
Plug caps 5k, plugs DR7
Mixture screw 2 turns out
Bowls are shiny clean
No leaks no overflow(relief)
What else, fully charged battery 12.38volts

Sent from my iPhone using Tapatalk

Can550 · « **Reply #24 on:** September 30, 2017, 05:45:53 PM »

Quote from: calj737 on September 30, 2017, 04:38:21 PM

Check the advancer mechanism to insure it returns from full advance.

Sorry being ignorant but how do I go about it
Thanks

Sent from my iPhone using Tapatalk

Can550 · « **Reply #25 on:** October 01, 2017, 07:55:38 AM »

When connected Morgan carbtune, all 4 tube gauges sit at the bottom unless RPM go above 2000-2500
All boots clamps are tight, new O rings in manifolds
Is it a symptom of air leak ?
Where do I start as have pulled carbs out about 6 times and tired now

Sent from my iPhone using Tapatalk

Can550 · « **Reply #26 on:** October 01, 2017, 07:56:39 AM »

Quote from: calj737 on September 30, 2017, 04:38:21 PM

Check the advancer mechanism to insure it returns from full advance.

Pulled it out, cleaned it and put back on. It was in correct order of installation

Sent from my iPhone using Tapatalk

Can550 · « **Reply #27 on:** October 01, 2017, 06:00:45 PM »

The moment I rev, it dies

Sent from my iPhone using Tapatalk

Can550 · « **Reply #28 on:** October 02, 2017, 07:45:46 PM »

Replaced intake insulators, timed it again, camshaft tensioner, new plugs caps, checked oil level and right away fired up. Synced and smooth.
Thanks everyone for guiding and helping

Sent from my iPhone using Tapatalk

News:

Author Topic: 1977 CB550K running issues - seeking help (Read 4097 times)