Author Topic: CB550F First start after total rebuild advice needed..*pics and video added  (Read 1174 times)

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Offline rosewood

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Well after 3+ years of working on this bike I finally got to start it up yesterday..very anxious moment as I've never rebuilt an engine from scratch before...It fired right up but i think I have some rich running issues..

Firstly I've rebuilt everything from scratch honed and new NOS rings new chains and bearings through out, lapped and rebuilt head etc..

I've rebuilt everything stock the only exception is a cheap reverse cone muffler on the end of the 4 into 1 factory F pipe and Dyna 3ohm coils with Hondaman resister pack.

Almost everything has been replaced and set up stock...

Dyna 3ohm coils + resistor pack
New Tec points plate including condensers
new leads and NGK plug caps
replaced inlet manifold o rings
new carb/inlet runner insulators
new airbox boots
new genuine airfilter
airbox breather setup stock
069A carbs ultrasonic cleaned and fully rebuilt:
NOS 38 slowjets
NOS 100 mainjets (I know these are meant to be 98's but i could only find Genuine 100's)
Benched syncd
float height 2.5-3mm from bowl verified with clear tube
idle screw 1 1/2 turns out
new fuel lines and vent and overflow hoses
new throttle cables (cables are fine and not biding anywhere)

I set the valve clearances after the engine rebuild 2 years ago (motor has sat for 2 years though since then, all lubed etc)
set points gap 0.35mm timing at F mark
checked good spark at each plug
primed engine first with drill on the alternator side nut to get oil flowing and pressure up with plugs out.

plugs are newish but I had used them before when I first tried to get the bike running 3 years ago they weren't cleaned but looked ok, gapped at 0.65mm.

Made a make shift Aux tank which hung probably 2ish meters from the ground.

I felt I covered all my bases and it fired right up after a couple of cranks..fiddled with the choke and idle screw as well as the throttle initially and managed to get it idling around 1000-1200rpm without too much bother. Mechanically it sounded fine..

A bit of smoke initially but not too bad...when I revved it though I was getting a bit of black smoke and then the revs would hang and take a while to drop, it would then die now and then but start right back up after hit the button with a bit of throttle, same thing though revs would hang when blipped throttle and a bit of black smoke. checked the timing with a light and it seemed pretty close idling and when revved (advanced). Left it at that and checked 1 & 4 plugs afterwards, both quite black and sooty (not wet) indicating a rich condition to me.

I plan to give it another go with cleaned or new plugs and drop the Aux fuel tank more inline with where the actual tank would be, check idle screws as I may have snugged them up a bit too tight before backing out. Will also have some vac gauges by then to get the sync right  failing that everything is set correct and I'm scratching my head a bit as to why it appeared to be so rich.

Would aux tank height effect mixture that much??
Would the assembly oil from the rebuild on the rings and cylinders (10-40 spectro oil) foul and soot the plugs quickly on the initial start up??

Does idle screw in lean the mixture on these carbs or is it the reverse?

Sorry for the novel just trying to give as much info as possible..

Any help appreciated and i will report back after attempt No 2.

thanks for reading
rosewood...
 
 
« Last Edit: February 11, 2019, 03:08:06 am by rosewood »

Offline sixthwisconsin

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Re: CB550F First start after total rebuild advice needed..
« Reply #1 on: February 10, 2019, 03:30:54 pm »
If the air screws are on the filter side of the carbs (and I think it is on these) then "in" means less air or richer. It's the opposite if the screws are on the engine side of the carbs like PD's.

Where are your needles? stock position?

Set your timing to 30º at full advance and leave it alone but for initial start up, the F mark is fine.

I never put an aux fuel tank that high. Just above the tank position is all you need but I wouldn't think it wouldn't matter. If your floats are functioning properly, they will stop the fuel flow. You would have had overflow if you had a problem.

It really sounds like you were very thorough with your build.
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Offline rosewood

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Re: CB550F First start after total rebuild advice needed..
« Reply #2 on: February 10, 2019, 03:49:57 pm »
Sorry forgot to mention needles....stock keihn 069a needles second notch from top, emulsion tubes clean etc etc..

If my screws were too tight before backing out that makes sense that it could be on the rich side but i cant see how it would make that much difference....then again this is all new to me..

Yes I've done a lot of reading on this site over the last three years to get to this point and tried to do everything properly, was really hoping everything set up right would see it run well but I guess that was wishful thinking..

hopefully I'm not far off...and attempt 2 goes better..

thanks for the reply..

if i have time i throw some pics up and maybe upload a video to youtube..


If the air screws are on the filter side of the carbs (and I think it is on these) then "in" means less air or richer. It's the opposite if the screws are on the engine side of the carbs like PD's.

Where are your needles? stock position?

Set your timing to 30º at full advance and leave it alone but for initial start up, the F mark is fine.

I never put an aux fuel tank that high. Just above the tank position is all you need but I wouldn't think it wouldn't matter. If your floats are functioning properly, they will stop the fuel flow. You would have had overflow if you had a problem.

It really sounds like you were very thorough with your build.

Offline scottly

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Re: CB550F First start after total rebuild advice needed..
« Reply #3 on: February 10, 2019, 05:17:09 pm »
.fiddled with the choke and idle screw as well as the throttle initially and managed to get it idling around 1000-1200rpm without too much bother. Mechanically it sounded fine..


The choke should be fully open and the motor warmed up before attempting to adjust the idle mixture and speed.
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Offline sixthwisconsin

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Re: CB550F First start after total rebuild advice needed..
« Reply #4 on: February 10, 2019, 06:13:04 pm »
You got it running with your detailed work so don't jump to fiddling with anything too quickly. Take your time and adjust one thing at a time. Reset you air screws to 1.5 turns. I believe that makes everything stock except for the 100 mains and I would not worry about that yet.

Get it running and warmed up with a fan running on the cylinders. Check timing then balance the carbs. If you did the bench synch properly then you are probably really close.

With the last cb550k I did, I ended up with 100 mains compared to the 90 stock with a stock airbox and a Delkevic exhaust. I guess my point is I rode 300 miles to butt tune the bike so don't be in a hurry to get it running perfect. Sometimes you just need to ride & think to tune these (at least that is what I do).
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Online calj737

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Re: CB550F First start after total rebuild advice needed..
« Reply #5 on: February 10, 2019, 07:30:36 pm »
Hanging idle then dying is a sure sign of a vacuum leak and running lean. Make sure you’ve cinched up the carb boots tight and that the carbs are fully seated into them.

Don’t get too hung up adjusting things yet. A rebuilt motor needs a chance to settle in. Choke to start, fan blowing, get it warmed up. Maybe vacuum synch the carbs and target the 1,200 RPM idle range (synch at 2,000).

Get some miles on it, some decent revs above 4,000 to get the motor settled in. You’ll be fine, you’re just a new “Dad” and being overly anxious  ;)
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Offline rosewood

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Re: CB550F First start after total rebuild advice needed..
« Reply #6 on: February 11, 2019, 02:31:37 am »
Cal pretty sure no vac leak i did spray parts cleaner at all the boots on that first run and didnt appear to have an effect on anything....I def think its rich judging by the plugs they are very sooted.

So gave it another crack tonight...cleaned plugs dropped the aux tank and reset the idle screws they were a bit snug probably a quarter turn too much in to start with so redid them all to 1.5 turns out again...

This time i started with choke on full and then opened up choke soon after and controlled the revs with the throttle for a while while letting it warm up. didnt rev it too much as just wanted to stay in the idle range while warming. Once things had settled it seemed to be idling ok but very similar to last time giving it throttle saw black smoke out the muffler and the revs did hang a bit but not as bad as last time.

Turned it off and backed the screws out again 1/2 turn more didn't seem to change much so repeated again another half turn similar again plenty of black smoke out the exhaust when revving. checked for leaks again with parts cleaner but didnt change anything.

Turned it of after that and checked plugs very black and sooty again.

Stood back and looked at the carbs thinking i should check the float height again...and while doing this had a brain fart moment...I've got a custom top triple on the front i made and being flat compared to the factory one with the forks poking through 1cm or so the front is actually sitting quite alot lower at the front compared to stock. Also while I was running it tonight i had the back on a paddock stand raising the rear wheel quite a bit off the ground. Yesterday it was on the drive inclined up which would have even the bike out though. but tonight i was set up in the garage on a flat surface.

You can see from the pic the angle the carbs are sitting on...So i took a few pics and rechecked the float height on No1 carb with a level for reference. I have no idea if this could be the problem but im picking float height might be a bit high especially with angle of the carbs. I rechecked my notes and when set up on the bench perfectly level they were all between 3-3.5mm from the top of the bowl.

I really hope this is my problem and that the idle and main jet are seeing to higher fuel level causing it to run rich??

Take a look at the pics and see what you think...

Offline rosewood

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Re: CB550F First start after total rebuild advice needed..
« Reply #7 on: February 11, 2019, 03:03:20 am »
Also uploaded a couple clips on you tube first is an edit i did and the second a side view of the first start with the hanging idle issue towards the end. hopefully you can see the smoke as its revved..

Also before anyone flames me I am a complete novice with bikes especially rebuilding an engine from scratch and trying to get it running so i may have done a few things wrong....if so I'm happy to take on any advice but take it easy on me  ;)



Offline seanbarney41

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Did you replace the o rings between the intake manifolds and the cylinders?
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Offline 540nova

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One thing to consider is, it takes time for your rings to seat and bed in, and a rebuilt engine needs some RPM upon initial fire-up. Idling is the worst thing for a fresh rebuild.
To properly break in, put a strong fan on the engine, start up, and modulate the throttle from idle to approximately 3/4 , continuously, for a solid 20 minutes. Shut off, let it cool down.
After 20 minutes, if weather doesn't allow a ride, repeat.
If you can take it out on the road, run it through the gears, 3/4  to full throttle, up to about 60% redline, in each gear, to top gear, then down shift, using engine braking, through each gear, down to 1st, repeat for 20 minutes.
Ride moderately first 500 miles.
This is the procedure given to me by Frank Giannini,  of Giannini Racing. Google him, he KNOWS. Honda Factory Team head mechanic, and racer.

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Offline Korven

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Re: CB550F First start after total rebuild advice needed..*pics and video added
« Reply #10 on: February 11, 2019, 08:53:38 am »
One thing to consider is, it takes time for your rings to seat and bed in, and a rebuilt engine needs some RPM upon initial fire-up. Idling is the worst thing for a fresh rebuild.
To properly break in, put a strong fan on the engine, start up, and modulate the throttle from idle to approximately 3/4 , continuously, for a solid 20 minutes. Shut off, let it cool down.
After 20 minutes, if weather doesn't allow a ride, repeat.
If you can take it out on the road, run it through the gears, 3/4  to full throttle, up to about 60% redline, in each gear, to top gear, then down shift, using engine braking, through each gear, down to 1st, repeat for 20 minutes.
Ride moderately first 500 miles.
This is the procedure given to me by Frank Giannini,  of Giannini Racing. Google him, he KNOWS. Honda Factory Team head mechanic, and racer.

Sent from my Pixel 3 XL using Tapatalk


When are you supposed to do your first oil change after first rebuild? I read in a tablet from early 70's that the oil (and filter) at 0km (guess the dealer) 300km and 1000km. Engine braking causing underpreasure in the cylinder that causes the rings to be pressed out.

Offline bryanj

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Re: CB550F First start after total rebuild advice needed..*pics and video added
« Reply #11 on: February 11, 2019, 09:17:50 am »
500 miles then every 1500 or every year whichever comes first
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Offline rosewood

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Re: CB550F First start after total rebuild advice needed..*pics and video added
« Reply #12 on: February 11, 2019, 12:12:38 pm »
Did you replace the o rings between the intake manifolds and the cylinders?

Yes and have sprayed parts cleaner in this area with no effect on the running...I did use generic 'O' rings though and the motor has sat for 2 years after rebuild but I'm confident i don't have a leak here..

Offline rosewood

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Re: CB550F First start after total rebuild advice needed..*pics and video added
« Reply #13 on: February 11, 2019, 12:20:55 pm »
Thanks for this info nova...I am conscious of this break in and haven't hadn't running too long like this. I just need to get it in the ball park first and quickly...Next time I will definitely give it alot more rpm as you describe regardless of the rich condition.   

The bike is not road worthy yet, still need to finish off a few things before I get it warranted and registered (NZ talk)..I'm also tempted to take it to a dyno for this as well...


One thing to consider is, it takes time for your rings to seat and bed in, and a rebuilt engine needs some RPM upon initial fire-up. Idling is the worst thing for a fresh rebuild.
To properly break in, put a strong fan on the engine, start up, and modulate the throttle from idle to approximately 3/4 , continuously, for a solid 20 minutes. Shut off, let it cool down.
After 20 minutes, if weather doesn't allow a ride, repeat.
If you can take it out on the road, run it through the gears, 3/4  to full throttle, up to about 60% redline, in each gear, to top gear, then down shift, using engine braking, through each gear, down to 1st, repeat for 20 minutes.
Ride moderately first 500 miles.
This is the procedure given to me by Frank Giannini,  of Giannini Racing. Google him, he KNOWS. Honda Factory Team head mechanic, and racer.

Sent from my Pixel 3 XL using Tapatalk

Offline BomberMann650

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Re: CB550F First start after total rebuild advice needed..*pics and video added
« Reply #14 on: February 12, 2019, 12:10:31 am »
You mentioned your plugs were gapped at .65

That large of a gap could be causing some instability as you rev up.

Get that gap down to stock.  High revving engines like small plug gaps.
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Offline rosewood

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Re: CB550F First start after total rebuild advice needed..*pics and video added
« Reply #15 on: February 12, 2019, 02:59:53 am »
Whats the stock gap for a 550F?

My Honda workshop manual says 0.6 - 0.7mm. My Haynes manual says 0.7 - 0.8mm. I thought 0.65 was a good compromise.



You mentioned your plugs were gapped at .65

That large of a gap could be causing some instability as you rev up.

Get that gap down to stock.  High revving engines like small plug gaps.

Offline BomberMann650

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Re: CB550F First start after total rebuild advice needed..*pics and video added
« Reply #16 on: February 12, 2019, 05:26:35 pm »
Whats the stock gap for a 550F?

My Honda workshop manual says 0.6 - 0.7mm. My Haynes manual says 0.7 - 0.8mm. I thought 0.65 was a good compromise.



You mentioned your plugs were gapped at .65

That large of a gap could be causing some instability as you rev up.

Get that gap down to stock.  High revving engines like small plug gaps.

Crap, I was thinking inch scale... Nevermind!
 You're fine.

Are you revving with the choke completely off?  The times I've heard my 550 run like that it was either with choke on, low fuel, or no spark in 2 cylinders.

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Offline rosewood

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Re: CB550F First start after total rebuild advice needed..*pics and video added
« Reply #17 on: February 12, 2019, 07:05:41 pm »
Lol no worries Bomber..

I cant quite remember....I may have had it on initially revving but I did try to turn off as soon as I could. This was the first time ive ever had it running properly and am new to these old bikes and bikes in general.

The second attempt (not these youtube clips) I did flick the choke soon after it fired and held the revs with the throttle, will be doing this again next time.

Side note.... I reached out to HondaMan who has given me a lot of advice over the last few years on this bike. He has suggested a couple of things the main one being replace the automotive hose clamps at the inlet runners/carb with the proper narrower Honda ones as he suspects an air leak even though I checked while running.

My old ones were pretty beat up but I managed to straighten them out a bit and get them fitted last night. Could it be as simple as this? I guess ill find out soon...

rosewood



Whats the stock gap for a 550F?

My Honda workshop manual says 0.6 - 0.7mm. My Haynes manual says 0.7 - 0.8mm. I thought 0.65 was a good compromise.



You mentioned your plugs were gapped at .65

That large of a gap could be causing some instability as you rev up.

Get that gap down to stock.  High revving engines like small plug gaps.

Crap, I was thinking inch scale... Nevermind!
 You're fine.

Are you revving with the choke completely off?  The times I've heard my 550 run like that it was either with choke on, low fuel, or no spark in 2 cylinders.

Offline rosewood

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Re: CB550F First start after total rebuild advice needed..*pics and video added
« Reply #18 on: February 13, 2019, 12:51:04 pm »
Well i gave it another go last night with the old clamps installed again......Didn't run it to long but kept the revs moving as i didn't want it to sit at idle too much....

The hanging revs did seem to be a bit better this time but still very rich blowing black smoke when revving...once i was confident it had warmed enough i tried adjusting the air screws both in and out this did change the idle but. it seemed richer in and then struggled to run further out but either way i was still very rich when revving. stock idle position seemed the best imo..

With it smoking when revving im thinking now its probably more associated with the mainjet / needle jet circuit and possibly bowl fuel level. Im really trying to eliminate all factors stock first before i adjust the needle position or play with the fuel level..

After this short run i noticed a decent puddle of fuel under the bike from No3 carb it had obviously overflowed  so that could be the reason why that cylinder is rich but doesnt explain the other three? All plugs look very identical and sooty...I then cleared tubed 1 & 4 on the bike and they seemed ok.

Im going to go through this carb again I have a spare old rack so ill check through the float pins and make sure i have good float pins and maybe install my keyster float valves as the originals have a step on the taper even though they appeared to close off fine when i put it together and bench checked heights but No3 was definitely playing up.

Can anyone tell me the size of the O rings on the inlet runner to cylinder head, i want to double check i have the right size as this could be another source of leak i would like to eliminate even though they have been replaced.

After I pulled the carb there was signs of fuel in the runners and in the hoses in all 4. not sure if this is normal but its indicating to me that too much fuel is getting through.   

Been a very frustrating last few days.... 
« Last Edit: February 13, 2019, 12:53:09 pm by rosewood »

Offline addictedtocafe

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Re: CB550F First start after total rebuild advice needed..*pics and video added
« Reply #19 on: February 13, 2019, 08:52:19 pm »
From your video, it sounds crazy rich. Black smoke is an indicator of burnt fuel.

Quick easy check - if you put the choke on does it get worse or better? if worse, it is too rich and adding fuel makes it worse. If it gets better, it is too lean and adding fuel will make it better.

If #3 is leaking fuel on the floor, it's not sealing at the seat as you suspect.
You can try polishing the seat with a q tip chucked in a drill and some brasso. I don't know how the keyster kits are for these bikes, but on my suzuki t500 they were hot garbage.

Main jet, needle position and all that other stuff shouldn't make any difference at idle. it's the mixture screws and the idle jets. Assuming the jets are clean you can mess with the screws. Get a good vacuum gauge or quad gauge setup, adjust the mixture screws for highest vacuum in each cylinder. Then you can adjust the throttle valve openings for sync.

There's my 2 cents for ya. Start small and work your way up. Get it idling, then work on higher throttle openings.

here's some good videos that might help.

Bike looks great, by the way. Good luck!

Offline rosewood

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Re: CB550F First start after total rebuild advice needed..*pics and video added
« Reply #20 on: February 14, 2019, 03:33:05 am »
Thanks alot for posting that addicted...I will watch and take it all in. Alot of it ive read before its just putting it into practice.

I'm just so far out at stock settings its telling me something is seriously wrong to be passing that much fuel.  I think at idle its not to bad but as soon as it gets any throttle its very very rich.

A side note these carbs on the bike were pieced together from the original 069a carb and spare set i picked up. 2 bodies from each due to stripped threads....both sets were in pretty poor shape with alot of corrosion on the main jet/emulsion post. both from neglected bikes poorly maintained and haven't run for years hence the reason for sourcing NOS jets..im just starting to think they are passing way too much fuel through the mains as soon as it gets any throttle. Maybe the mainjets are not sealing in their seats properly??

I do also have a set of 627b's that are alot cleaner inside even though they havent been used for a long time. Im going to try and clean these up and piece together another 069a equivalent with the spare set of needles and emulsion tubes i have. the float valves and float pins and and jets are in a lot better shape also. I just think using these carb bodies i am in a way better starting position compared to what i have currently. alot of pissing around but I think its worth a try as I'm running out of options before i have to resort to dropping the needle..



Offline Deltarider

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Re: CB550F First start after total rebuild advice needed..*pics and video added
« Reply #21 on: February 14, 2019, 07:22:18 am »
... adjust the mixture screws for highest vacuum in each cylinder...
That won't work, I'm afraid. Check choke for good functioning. The little O-rings around the main jets should be in good order and seal well. Set airscrews as prescribed or maybe a bit leaner. Then sync the carbs. Then adjust the airscrews NOT for a highest rpm but thus that bike accelerates well. This may result in an idle on the rich side. 
« Last Edit: February 14, 2019, 07:29:34 am by Deltarider »
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Offline scottly

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Re: CB550F First start after total rebuild advice needed..*pics and video added
« Reply #22 on: February 14, 2019, 05:19:01 pm »

I'm just so far out at stock settings its telling me something is seriously wrong to be passing that much fuel.  I think at idle its not to bad but as soon as it gets any throttle its very very rich.

A side note these carbs on the bike were pieced together from the original 069a carb and spare set i picked up. 2 bodies from each due to stripped threads....both sets were in pretty poor shape with alot of corrosion on the main jet/emulsion post. both from neglected bikes poorly maintained and haven't run for years hence the reason for sourcing NOS jets..im just starting to think they are passing way too much fuel through the mains as soon as it gets any throttle. Maybe the mainjets are not sealing in their seats properly??


If there was a lot of corrosion, that may be the problem. Do your carbs have the leaf springs that push the main jets up when the bowls are installed?
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Offline rosewood

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Re: CB550F First start after total rebuild advice needed..*pics and video added
« Reply #23 on: February 14, 2019, 06:32:24 pm »
Yes they have the leaf spring....I will inspect them all closely tonight..

I did post a pic of the corrosion in this post a while ago..

http://forums.sohc4.net/index.php/topic,173751.50.html

Two of these bodies were swapped out but the ones I replaced them with were also similar..

Once i inspect again I will post a pic of them tonight but the No3 I have checked in my opinion should seal judging by the the force need to press it in.

Offline TwoTired

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Re: CB550F First start after total rebuild advice needed..*pics and video added
« Reply #24 on: February 14, 2019, 07:45:48 pm »
I skimmed the thread. Maybe I missed something.  But, 069A carbs were tuned for a stock engine , the stock F muffler, and the stock air filter.  If any of those things change, the carbs will never deliver proper fuel mixtures with the stock tuning parts and settings.

The pilot air screws set the throttle response off idle under load. )More about this later) It will run rather rich at idle, but not so much as to black foul spark plugs.

You need a dyno or a test track to find out what jets, slide needles, and setting work best for your newly engineered set up.

First verify fuel level in the carbs using clear tube test.  Too high level will soot up spark plugs. 2-3mm below float seal seam.

If you won't take it to a dyno to get a fuel map print out, you will need to learn to read spark plug tips.  Find a test drive area, stop the motor and put in fresh clean spark plugs, while the engine is at operating temp.  Get on the bike and with the throttle wide open run through the gears to top speed.  Hit kill switch and pull in clutch, coast to stop and remove spark plugs.  The deposit patterns will tell you if you need larger or smaller main jets.  If the tip insulators are light brown going whiteish, the main is good size.  Going dark, too rich, full white too lean.
  Now you need to set the needles.  Mark your throttle so you know where half throttle is.  Again with clean plugs, Start up and run through the gears using only half throttle to get color on your plugs.  Still looking for light tan going white.  Sooty, drop needle lower, too white, raise needle.

What remains is to determine if the needle taper is good.  With the slide set for best half throttle, now use clean plug to test 3/4 throttle position operation. at end of run plug the plugs and read deposit patterns.  If still tan going white, your needle taper is likely good.  If rich or lean deposits show, you need different taper needles.  Try ones from 022A, or 627b carbs.  Repeat finding the needle position with the half throttle plug chop test.  With luck your 3/4 and 1/4 throttle will keep your plug deposits good.

When/if you get success to this point, now set the air bleed pilot screws.  Get the bike moving and put it in top gear, so the engine will get full load.  Open the throttle suddenly to half way.  If the engine wheezes and quits, then resumes with throttle return, the idle mixture is too lean, turn in the screws a bit at a time, until the bike picks up reliably, if not powerfully.  If you can whack the throttle full open and the engine picks up, the idle is too rich and the air screws should be turned outwards to lean it.  A too rich mixture will foul spark plug during prolonged idle, leading to misfires and burbling recovery with throttle changes, as the plugs heat and clear themselves.

Good luck!


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.

 

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