Topic: 78 CB550 Project

[Beep Bop]

Hi guys,

As I posted in the greetings a little while back I've made some progress with my non-runner 550.

I'll be posting a few questions on here so I would greatly appreciate input on moving this project forward.

Harrisluv has been great in helping me get a set of carbs rebuilt, the old ones were too far gone to save with corrosion and pitting.

I've since installed a new 4into1 ignition coil, new daiichi condenser, oil filter and exhaust.
Adjusted the valves (a few times to be sure) and points.
Motor turns but after an initial dry and then wet compression test we are looking at (cyl1)110 ,(cyl2) 80,(cyl3) 120,(cyl4) 40.
Numbers went up a little with the wet test but plateaued.

Needless to say its likely rings and head gasket. Either way a rebuild will need to happen.
I've got a Vesrah gasket set with the extra 4 sealing rubbers and an engine oil seal kit (4into1).

So I am likely going to need help from a shop with cleaning up the cylinder walls and then look at new rings or larger pistons depending on the condition.

So,*My question here is would it make sense to source a 2nd hand set of pistons with cylinder jugs and just swap those in instead? (with the new vesrah gaskets of course).
Something like this:

http://www.ebay.com/itm/74-HONDA-CB550-CB-550-K0-HM801-ENGINE-CYLINDER-JUG-BARREL-TOP-END-PISTON-SET-/291282050925?hash=item43d1c35f6d:g:tpwAAOSwR0JUQXMi&vxp=mtr

Would greatly appreciate any insight on this as I will be looking to pull the motor before the end of this month.

[SOHC4 Cafe Racer Fan]

Before you panic, it is very common for a motor thats sat a while to have the rings gummed up and not seal well. My strongest advice is to get the motor running, run it around for 100-200 miles with fresh gas, fresh plugs, and high RPMs. This will help un-goo the cylinders and valves.

Then, check your compression again. See what improvements may have come of it. You can also try a tank of fuel additive to help clean up the rings. Its not a guaranteed solution, but you might be surprised at the results.

As to whether I'd run 2nd hand pistons and rings, probably not. You don't really know that you'll be any better off than you are now. Your cylinders might just need a good hone job and the rings cleaned if there's little wear.

Fresh oil, too.

[Beep Bop]

Thanks for the insight guys.

I've got some fresh oil,filter,plugs installed so all good to go.
Going to check I've got spark since I've installed the new coil pack.

Apart from that its, slap the carbs on, get some gas and go for it I suppose.

There is also a gearbox issue with it which I haven't gotten around to yet.
Bike goes down to first and back up to Neutral fine but it wont click up into 2nd or above.
Clutch cables are disconnected but this shouldn't make a difference right? 

[Beep Bop]

Just a quick update!

I rolled the bike and sure enough it went up gears fine which was a great relief.

Slapped the rebuilt carbs on from Harrisluv, ran some fuel down a fuelhose and a funnel in to the fuel inlet on the carbs.
( I dont have the tank hooked up and there is also a vaccum inlet on the pd46cs which I've left unhosed).
I used a fresh battery with the electric starter and it cranked fine but didn't fire.
I already checked all the plugs (grounded against the motor) and had good, blue, spark.

The fuel level in the hose and funnel wouldnt go down though.

I tried afew sprays of carb cleaner and it fired up for a couple seconds then died.
Checked the plugs beforehand and they weren't wet nor smell of fuel.

Bowls all drained well. It just seems like the fuel isnt getting from the carbs to the engine.
I kept an eye on the rubber pieces between the inlet and carbs and they seemed sealed and again, dry apart from the carb cleaner.

Felt really close to getting there today, any suggestions would be great!

Thanks,

Paul

[Beep Bop]

Just to update on this, I went back over timing and valve adjustments.

Re-adjusted my valves and confirmed intake (0.002) and exhaust (0.003), did the O's on "T" 1.4 and rotated 1 full revolution to do the Xs per the manual.

Hooked up the fully charged battery.

Then went to re-gap the 2 points (.013 on 1&4   and .015 on 2&3 ).
Next I hand cranked to "F" 1.4, Loosened the points plates and got the test light out.
Grounded the test light in the points cover hole and used the croc clip onto the end of the 1&4 point (where the condenser cables meet the screw).
Rotated the points plate to where the light was just coming on and tightened down the 3 screws around the main points plate.
Hand cranked to "F" 2.3, Moved the croc clip onto the screw at the end of the 2&3 point.
Adjusted the mini plate to where the light just came on and tightened down.

Next, to be sure I pulled all spark plugs out, grounded and checked for spark. All came back strong.

I then took off the carbs again and made sure there was no opportunity for air leaking between the carbs and inlet.
Re-attached the carbs, tightened up the clips, and hooked up both throttle cables as well as the choke.

Ran the new fuel line also provided by Harrisluv into a funnel. Filled it up with Gas and kept it suspended above the carbs.
Put the choke on and twisted the throttle a few times.
I cranked the engine using the starter motor and after a good few seconds (4-6 seconds) nothing.

I then tried some starter fluid spray into the carbs and hit the starter motor.
Motor immediately comes alive and sounds great. Effortless start and dies in about 5 seconds.

Immediately observed warm exhaust pipes on all 4 cylinders.

I tried a few times without the starter fluid and also waited to recharge the battery to ensure full cranking power - No luck.
I tried a few times with the choke on and no twist on the throttle as well as wide open no choke - no luck.
Ran it again with the starter fluid + choke and it fired up quick and ran abit longer too before dying.

I could see in the funnel that the fuel level had not changed.
Checked the plugs and they were moist and had some soot on them too.

I haven't fiddled with the carbs at all at this point and I didnt have a chance to check for any compression changes afterwards.

It was great hearing it run though.

I feel like I am very close but would really appreciate any pointers.

[RAFster122s]

Dropa float bowl or bowl drain screw to see fuel level. Might have gotten the Samsonite Gorilla @ USPS/UPS/FedEx drop it hard enough to hang the floats stuck in the off state, and that would prevent the fuel from reaching the carbs.  Is your choke lever in up or down position when you have it on....easy for folks to confuse the position and choke operation.  Should be up when starting the bike and normally after tuned it would require about 1/2 choke until warmed up.
It is firing on starting fluid which is a highly volatile vapor, so it is running on that until it cannot.
As Cal suggested, pull your plugs after attempting to start bike and tell us if they are wet or dry.  Did you rotate the motor clockwise or counterclockwise?
Rechecking 1&4 might be adviseable to ensure it didn't drift and rechecking 2&3 does not hurt while there and only takes a moment.

Sounds like your carbs are not flowing fuel for them to not change at all, but it will not guzzle it down, given you can get 50 mpg on the 550.

[RAFster122s]

If Havoline were compatible with our motorcycles I would suggest you use it as a high detergent motor oil would loosen up any crud and possible help the rings as well. 
Do not Cal advised High rpm operation, so highway operation or reving it up through the gears going past 5 k or you aren't riding it hard enough.  Tough to keep it above 5-6 k in most cities.  Don't know that I would wind it up to 5k in first, but the rest of the gears it would do it good...just be listening for any bad noises that come on or pop up when doing it.  Do a good bolt/nut check to ensure everything is tight will eliminate or lessen any noises from vibration.  Don't forget many of the motor fasteners are very low torque values.  So, don't crank on something and break a bolt or stud.  You are looking for loose stuff, not retightening anything unless it is very loose or loose, knowing the torque values in the manual.

Post what you find on the plugs.

You can use a car's battery with jumper cables to serve as a supplemental power source when the car is not running.  It will allow the bike's battery to not be drained as far.  It is not a good thing to deep discharge a std lead acid wet battery.

David

[Beep Bop]

Thank you all for the insight and suggestions.
I'll clear tube the carbs (pd46Cs) as my next step in diagnosing this issue.
Please let me know if there are any other areas to focus on and look at.

RAF,
As mentioned in the previous posts, the plugs were dry when I cranked without starter fluid.
I believe the most recent attempt with the starter fluid explains the moist on the plugs but it was not "wet" with fuel.
I'll take additional notes on the plugs on attempts going forward.
When doing both Timing and valve adjustments I rotated the motor clockwise.

Cal,
I agree that it just doesn't seem to be getting fuel from the carbs into the chambers. 
The carb bowls fill no problem ( will get clear tube measurement ahead of next post).

What are the typical problems for fuel not getting in to the chamber from the carbs?

I would also like to add one more variable that I neglected to mention, I currently do not have the airbox attached.
I have left the carbs open to atmosphere (they are jetted to run with the airbox) in order to easily spray the carb starter.

Would this effect drawing fuel from the carbs into the chambers?

I've read a few threads on the importance of having vaccum throughout the intake. Could not having the airbox on somehow result in fuel not moving from carbs to chamber?

Any thoughts? I like to have a few ideas and areas to diagnose when Im troubleshooting!

Thanks,

Paul

[Beep Bop]

Cal,

Regarding, valve adjustments I want to clarify a piece of information.
As I understand it, we start at 1.4 make appropriate adjustment for either X or O (depending which tappets are loose).
Hypothetically, if I adjusted the Os first with "t" @ 1.4 (being that they were loose tappets) I would then make one full revolution from 1.4 back to 1.4 and adjust the the remaining tappets (X), correct?

When you mentioned:
" Repeat for 2-3."
You've got me confused.

Perhaps my compression woes are waring on me.
Do I need to have compression in order to create a vacuum to pull the fuel from the carbs into the chamber?
What does the bike running on starter fluid say about compression?

-------------------------------------------------

So as a mini-update from the last weekend.

I didn't get a chance to clear-tube it last weekend, will be doing so this weekend.

I got abit liberal with the starter fluid and no surprises but she ran until that all got burnt up.
Attached some photos of the plugs which again are dark because of (i assume the starter fluid).
I also took the opportunity to spray starter fluid around the rubber seals (whilst the engine was running under starter fluid) to listen for surges implying a leak. No leaks as far as I can tell.

I also attached a picture of my current fuel setup which is in essence a tube with a funnel on it held above the carbs.

[Beep Bop]

Quick update, ive been clear tubing the carbs.
All levels show about 1cm under the base of the carb (where the bowl meets carb).
Is the fuel level too low ?
I've gone back over my valves and I feel confident with the set up there.
Been trying to start it but no luck on its own

[Beep Bop]

Cal,

Thanks for the info. Im goina look into readjusting the floats for abit more fuel.
I'll speak with Harrisluv and see where he recommends that to be.
Really hoping that solves all of this starting business and I can move on to the other myriad of of issues haha.

[harisuluv]

Seems odd that they would all be totally the same but 10mm below the line.  The 550PD carbs are pretty straightforward.

It kind of sounds like you unhooked the gas, took the carbs off, then performed the clear tube test.  With no gas to refill the bowl.  Therefore if you emptied the clear tube out into bowl it would be at the correct level. 

In other words, the carbs still have to be hooked up to gas to perform the clear tube test.

[Beep Bop]

Harisuluv,

Thanks for the comment.
I put the bike on it's center stand and clear tubed with carbs on the bike.
There was still fuel in the funnel so there was a supply going to the carbs.

I don't have a working camera at this time as photos would definitely help clear this up.

As Cal put it, my current readings for where the fuel is in the tube is 1cm/10mm below the bowl seam.

[Beep Bop]

Update

So I gave it one last clear tube before I opened up the carbs and tried a few different things in the process.

Put more fuel in the funnel, put a few drips into the cylinders from the spark plug holes.
Even put a few drips directly into the carb inlets.
I held the choke on full manually (using a screwdriver as opposed to the cable).
No starter fluid.

Cranked it and she started.
I held the chokes shut as tight as I could and the bike ran for almost 2 minutes.
She accepted a little bit of throttle (1/4 at most) then began to struggle.
Fuel was visibly lower in the funnel afterwards.

My theory is that the choke being nearly completely shut allowed enough vacuum and for the right fuel : air mixture to enter the chamber.
Does this sound plausible?

I'm thinking my next step is to reattach the airbox and see if that will help limit the air in the same way I held the choke shut.

Any thoughts on this? It kind of makes sense to me as the carbs were jetted for an airbox and its been nothing but open carbs uptil this point.
How temperamental are these cb550s without airbox?

Also bonus question:  can anyone tell me if the 550F flip tank is the same tank as the 78 550K?

[Beep Bop]

I've been trying to post with pics for the last couple of days but no luck..

Anyway heres another go at it.

Thanks for the advice Cal, I wont be putting fuel down the chambers anymore.
I re-installed the airbox but as its missing alot of hardware from the PO I might have to source some screws at the hardware store or something.

So the key question right now is how can I stop the leaning and richen it up?
It sounds like I need to restrict air or increase fuel.

I've tried the airbox and she'll start without the starter fluid but choke has to be held shut and I need to give it some throttle otherwise it drops and dies.
*Carbs are also making popping noises*

Thoughts on the Idle mixture screw?

Im going to go over all the rubber seals again to be 100% sure. I also sprayed starter fluid around the seals when she was running but no change.

I've attached photos from last weekend when I did the floats. 

[Beep Bop]

Seems it wont let me post with any attachments.. strange!

[Beep Bop]

Cant seem to attach the photos so I've attached a Google Link to the 4 fuel levels :

https://goo.gl/photos/mVNQEE44i3WAMVRTA

[Beep Bop]

Okay, so I need to adjust 1 & 4.
In theory is this going to solve the leaning out issue or is this another beast altogether?

[Beep Bop]

Cal,

Thanks for the reply.

The carbs are 100% rebuilt by Harrisuluv/James and I have been reluctant to touch them in any way.
The reasoning here is that I understand there are only going to be more variables with getting the bike started if I have to worry about the carbs.
I agree and like to think that with James' work eliminates any questions of issues with the carbs.

With that in mind, i did try out some new rubber boots between the carbs and intake manifold and it does seem to have helped startup.
I let it run to the point it warmed up and a new issue emerged where it started backfiring - indicating ignition.
Other observations as it warmed up was that it would occasionally (once or twice) be able to start without choke.
The Revs would surge when throttle was applied.

I am waiting on a shipment of 78 airbox rubbers from Paul Gabor which I will put on this weekend and report on.

[Beep Bop]

Attached a video of her warmed up and idling.
What is the ideal idle speed for these? Also will it just be a case of tuning based on Idle Mixture screw?

If I try to rev it without choke on, it dies.

https://sohc4-forum-attachments.s3.amazonaws.com/VID-20170506-WA0009.mp4

[Beep Bop]

Well folks, she lives and is better than ever.
For anyone who is going through something similar I've come back to leave some feedback.

Turns out it was very much a case of needing a top end rebuild, Cyl. 4 needed new rings and a new piston as it was only holding compression when wet.
New set of rings and now she runs sweet.
Theory on how this happened was that the PO had destroyed the threads on the sparkplug for cyl4.
Letting the bike get exposed to the elements and rain corroded out was left of the rings.

I was fortunate that the cylinder walls were some how in great shape and only needed a hone.

Anyway, hope this helps. Glad after nearly 2 years I now get to ride.

Other things that got done since the last update, forks have been rebuilt, cleaned up the electrics, front and rear brakes including BMC rebuilt and fixed up the turn signals and rear brake lights.