Author Topic: 75 550k Advice (Read 2830 times)

fletcha221 · « **on:** July 12, 2010, 07:46:56 PM »

Bought a 75 550 that has been sitting since the mid 80's. Rebuilt the carbs, replaced the petcock filter, dyna-s, the normal restore stuff. However, one thing has be baffled. The bike has jardine 4-2 exhaust, but the bike had (and has new) 100 jets. The bike has the stock air filter, and all the ait screws are 1 1/2 turns out. I fire the bike up, and after adjusting the dyna-s plate to get the bike running "OK". However, the engine is knocking, and it seems as though it's having a hard time staying running at idle. When I crack the throttle, it jumps right up, but I can't get the bike to rev past about 7500 rpms. When I lift off the throttle, the exhaust, the pipes crack and pop. From what I read in the FAQ section, the bike is running lean. I pulled the plugs, and they are (no suprise) white. Should I step the mains uo to 110's? Obviously the bike ran for the old owner, what the hell did I do? PLEASE HELP ME.

OldSchool_IsCool · « **Reply #1 on:** July 12, 2010, 08:11:15 PM »

Did you do the whole tune-up gambit? Tappets, cam chain tension, carb sync too?

Raef · « **Reply #2 on:** July 12, 2010, 08:29:47 PM »

are all the plugs the same and have you checked the pipe temps at the head?

if the plugs match with the knock I would say you still have a timing/points issue.
if it is more of a rattly rough idol it could be a carb sync issue.
if you really think it is lean I would check the needle heights you can gain a jet size or so by raising the needles ( lowering the clips)

I am running 118 (i made them) mains the needle clips 2nd from the top. the bike has Dyna coils and wires some head, exhaust and intake work a stock air box with a foam filter and the top open.

Mine starts to get lean about 8000 but will rev past 10,000

Mark

CBGhia · « **Reply #3 on:** July 12, 2010, 08:43:55 PM »

First, tune up-

You said you adjusted the plate to get it running "ok", that is not proper timing. You really need to get a timing light on that thing. You could be way off and still have it idle "OK".

TwoTired · « **Reply #4 on:** July 12, 2010, 10:29:02 PM »

Are all the head pipes about the same temp?

Have you cleaned the pilot jets?

Have you synced the carbs?

Have you done the routine 3000 mile tune up checklist?

Is the air filter clean as new?

fletcha221 · « **Reply #5 on:** July 13, 2010, 05:08:08 AM »

All of the plugs look the same....white:(

I did a bench sync with an 1/8 drill bit.

Pulled the E tubes, pulled the pilot and soaked everything in cleaner, then cleaned the carbs with forced air. Replaced the old jets.

The filter is still the old filter, but in decent shape. However, one is in the mail.

I suppose you are right about the timing light, however, I moved the plate and kept it wee the bike ran best. It worked with my other bikes:)

Is it possible the spark advancer is not working correctly?

I did not do anything with the tappets or cam chain. I was hoping to avoid fooling with that tappets.

Would the float level have something to do with these symptoms? Perhaps too low? I read the post stating that a greater pull results in less fuel.

Raef · « **Reply #6 on:** July 13, 2010, 05:30:09 AM »

setting the tappets on a 550 only takes about 30 min, but doubt that is your problem

the carbs on these bikes take some practice, I would get back into them making sure you can see light through the emulsion tubes and idol jets top to bottom and get at least a strand of wire through, check the needle heights.

when you get into the throttle the main jets join the idol jets, not replace them so the idols are still important and since there is no fuel pump or accelerator pump everything has to be just so or they are very moody.

Mark

fletcha221 · « **Reply #7 on:** July 13, 2010, 06:25:39 AM »

Raef,

I've never actually adjusted the needles, if I'm running lean, what should I do?

Raef · « **Reply #8 on:** July 13, 2010, 06:38:17 AM »

there are full manuals on this site, find the exploded view of your carb for reference.

you have to pull the top off the carbs and remove the slide. the needles drop down in the slides and the height of the needles is controlled by a clip, the lower the needle sits (higher clip position) the farther it goes into the main jet limiting the fuel drawn.

if you want more gas lower the clip (raising the needle)

I can't remember the locations but there are some very good articles in the tips and help sections seems like they are even divided up by bike.

i got to go if you don't find them PM me later I think I may have them saved some where

Mark

fletcha221 · « **Reply #9 on:** July 13, 2010, 06:44:06 AM »

Makes sense. I will try that later this week.

Still, one question remains. The bike will not rev over 7500 rpms. Do I need bigger main Jets? Again, The bike has the Jardine 4-2 exhaust.

fletcha221 · « **Reply #10 on:** July 13, 2010, 08:43:10 AM »

Anyone?

TwoTired · « **Reply #11 on:** July 13, 2010, 09:42:05 AM »

Quote from: fletcha221 on July 13, 2010, 05:08:08 AM

All of the plugs look the same....white:(

Not what I asked, but interesting. Evenly hot head pipes mean that all cylinders are firing and that there is roughly equal jet flow from all four carbs.
These engines will run on three. But, the idle is poor and the engine doesn't make full power.

Quote from: fletcha221 on July 13, 2010, 05:08:08 AM

I did a bench sync with an 1/8 drill bit.

That's seldom good enough for a smooth idle. Vacuum sync compensates for breathing variations between cylinders. Such as, valve tappets not set equally for each cylinder, differences in cam lobes, etc.

Quote from: fletcha221 on July 13, 2010, 05:08:08 AM

Pulled the E tubes, pulled the pilot and soaked everything in cleaner, then cleaned the carbs with forced air. Replaced the old jets.

It's the overlooked details that hinder success. You replaced ALL jets? With what brand? What else did you replace? If you reused the old pilot jets, did you verify they could flow fuel, liquid, or light? Your statement makes everyone assume you did it all right. But, if all was right you wouldn't be posting a problem.

Quote from: fletcha221 on July 13, 2010, 05:08:08 AM

The filter is still the old filter, but in decent shape. However, one is in the mail.

You cannot tell by looking at it if it is ok, only if it is really, definitely bad. However, white plugs are seldom a symptom of a clogged air filter. And, you are doing the right thing by replacing it. So, 'nuf said about that

Quote from: fletcha221 on July 13, 2010, 05:08:08 AM

I suppose you are right about the timing light, however, I moved the plate and kept it wee the bike ran best. It worked with my other bikes:)

Do your other bikes hope to reach 10000 RPM? "By ear" timing is not recommended for these engines, unless you lust after overheated engines and holed pistons.
And certainly not if you desire a smooth idle. Uneven,incorrect timing = uneven, incorrect idle.

Quote from: fletcha221 on July 13, 2010, 05:08:08 AM

Is it possible the spark advancer is not working correctly?

Certainly possible. Another thing to check with a dynamic timing light.

Quote from: fletcha221 on July 13, 2010, 05:08:08 AM

I did not do anything with the tappets or cam chain. I was hoping to avoid fooling with that tappets.

You plan on avoiding all routine maintenance? The bike is doomed.

Quote from: fletcha221 on July 13, 2010, 05:08:08 AM

Would the float level have something to do with these symptoms? Perhaps too low? I read the post stating that a greater pull results in less fuel.

If the floats were so low as to starve the pilot jets, yes. Could you have installed them upside down?

Good luck!

fletcha221 · « **Reply #12 on:** July 13, 2010, 11:18:04 AM »

1. All the head pipes are evenly hot.

2. I'm going to buy a Vaccum Sync. Any good ones out there that don't cost a fortune?

3. I replaced the Main jets only. Soaked the pilots and emulsion tubes in carb cleaner. Soaked carb bodies with cleaner, and blasted them with compressed air. The main jets are kehinin. Nothing else was replaced (besides bowl gaskets).

4. Nuff said.

5. I guess I got lucky with my cb350f, cause after getting the jetting correct with the pods, it ran perfectly, and as smooth as a babys bottom. Light brown plugs and perfect pull all the way to redline. How do you time a bike with the Dyna-S? Keep in mind, I'm a novice compared to you guys.

6. See above...I guess?

7. Hahaha, no I just want to try one thing at a time, that way I'm not doing 10 things at once, and not know exactly what was wrong and how I fixed it. I'd figure I'd bite off a little at a time so I don't have 10,000 pieces all over the shop and a completely broken bike:)

8. I cleaned the floats on the carb body, they never came off.

TwoTired · « **Reply #13 on:** July 13, 2010, 01:11:58 PM »

Quote from: fletcha221 on July 13, 2010, 11:18:04 AM

1. All the head pipes are evenly hot.

Good sign

Quote from: fletcha221 on July 13, 2010, 11:18:04 AM

2. I'm going to buy a Vaccum Sync. Any good ones out there that don't cost a fortune?

I bought my guages in 1975. They still work. I think it was $40-$50. I lost the receipt.

Quote from: fletcha221 on July 13, 2010, 11:18:04 AM

3. I replaced the Main jets only. Soaked the pilots and emulsion tubes in carb cleaner. Soaked carb bodies with cleaner, and blasted them with compressed air. The main jets are kehinin. Nothing else was replaced (besides bowl gaskets).

I'm going to assume your pilot jets are still plugged, then.
Take off one of the outer bowls, and remove the pilot jet (as opposed to the main). Can you see light through it?

Quote from: fletcha221 on July 13, 2010, 11:18:04 AM

7. Hahaha, no I just want to try one thing at a time, that way I'm not doing 10 things at once, and not know exactly what was wrong and how I fixed it. I'd figure I'd bite off a little at a time so I don't have 10,000 pieces all over the shop and a completely broken bike:)

I understand. But, I think the whole tune up is required before expecting the engine to run smoothly. You need to get 4 cylinders and four independent carbs to work together with equal fervor.
Of course, you could be lucky. However, sometimes you can plan your luck, by following established procedure.

Cheers,

fletcha221 · « **Reply #14 on:** July 13, 2010, 01:59:56 PM »

TwoTired,

You're a good man! Thanks for the advice. I'll be out in the shop, swearing, and trying to make sense of this all! I hope the problem isn't just as simple as the jardine exhaust with the stock #100 jets.

In your opinnion, if the pilots seem to be in order, when I have the carbs off, should I adjust the needles?

Kind Regards,

-Fletch

TwoTired · « **Reply #15 on:** July 13, 2010, 03:12:43 PM »

No need to swear. just plod through it. The bike never causes frustration. Frustration is caused by the mechanic.

Do you know what position the needles are in now?
Are these 022a carbs?

I have a 74 CB550 that I had 4 into 2 on it. Not jetting changes needed with the stock carbs and set up. The bike screamed to and beyond red line (frequently). I eventually put the 4 into 4 on it. It didn't seem to run any different, but the 4 pipes are heavier.

Anyway, *I* think you plod through and verify the entire tune up regimen rather than look for the silver bullet. Keep eliminating things it might be, until it is fixed.

Tappets (Cold)
Cam chain tension.
spark plugs cleaned as new.
Points cleaned gaped and timed. (you can static time with an ordinary 12V instrument lamp.)
Do check the advance, (if not with a timing light, take off the points plate and verify the weights swivel freely))
New air filter.
Verify compression equal on all four cylinders.

Which then leaves carbs as the only variable.
Clear pilots.
Vacuum sync.
Check fuel level in the bowls.

And, if the problem persists, then makes changes in the carbs.

Cheers,

fletcha221 · « **Reply #16 on:** July 13, 2010, 04:53:52 PM »

Yes, they are the 022a carbs, I'm not sure the position as of right now.

I think you are right. I suppose "Half-A$$ing" it will only make me more work down the line. I'll start with the carbs, make sure they are 100%, when move on with the rest of the tune.

I'll check back soon

fletcha221 · « **Reply #17 on:** July 16, 2010, 05:54:42 AM »

OK,

I'm an idiot. Never fully cleaned the Pilot jets. Pulled the carbs, cleaned them with some wire, carb cleaner, and compressed air, put them back in, and fired right up. Relatively smooth idle have only done a bench sync thus far. Battery was low, jumped it from another battery, bike came to life, then died when I disconnected the battery.

I figued I'd roll it down the hill and just drop the clutch and get her running that way..........NOTHING. Pushed 450 pound bike up hill.

I'm beginning to regret putting the Dyna on already. However, even if my 350 battery was dead, I could always kick start it.

I am having electrical issues, my right side turn signals do not work, but my left signals do. I tested the switch....it is good. I have something wired wrong in the headlamp.......the signals worked fine before.

With the ignition OFF, when I went to connect the jumper cables to the bike, it sparked.....leading me to believe something is wired hot....correct? I did some research and got some ways to test the charging system (thanks two tired), however, I think I'll be spending the new few days hunting down the electrical deamons.

Shouldn't the bike run even if the battery is dead? I understand the bike might not make enough juice at idle to charge, but I thought It would support it's own functions.

Any insight would help.

Raef · « **Reply #18 on:** July 16, 2010, 07:13:28 AM »

Won't kick or push start with out juice in the battery

TwoTired · « **Reply #19 on:** July 16, 2010, 10:06:10 AM »

Alternators and motors require a magnet for their basic function. Some bikes have permanent magnets in the alternator. These will produce power whenever they spin.
The SOHC4 has an electromagnet So, there is no magnet if it i not powered by electricity.
Even at that, the alternator has a power output vs. RPM curve. So, it doesn't make the same power at all rpms.

Turns out that the bike uses more power than the alternator can make at low RPMs. What the bike doesn't absorb from the alternator, it takes from the battery. If the battery gets depleted, it stops putting out energy to the bike, and alternator's electromagnet. The alternator output and the bike can't operate because there is no power to make the ignition spark.

If the battery is very weak, and you can still get it started, you must keep the alternator output higher than bike electrical demand by keeping the RPM above about 2500- 3000. That's about the only time the battery gets recharge power from the alternator. If you want the bike to recharge a dead battery, better turn of all lighting, and expect the engine to run at only high RPM for 6-8 hours. (or more).
The charging system is supposed to keep a charged battery charged, not recharge a dead one. Deeply discharging a starting type battery is bad for it and will shorten its operating life.

An SOHC4 without battery power makes interesting lawn art.

Cheers,

fletcha221 · « **Reply #20 on:** July 18, 2010, 10:14:56 AM »

hahahah! Fair enough!

Good advice guys. I put it on the charger earlier today. After while on the charger, I turned the ignition on, and i got a "pop" from what sounded to be the exhaust. Do I have a faulty ground? As i mentioned before,,,,I think something is "hot" all the time. the voodo of electricity continues.

TwoTired · « **Reply #21 on:** July 18, 2010, 10:53:41 AM »

That's probably the Dyna putting itself in operating condition/state during power up.
It can be pretty confused while powering up. Some things (and people) don't wake into a full state of readiness gracefully.

Electricity is not voodoo. It operates under precise and predictable rules. It was invented to illustrate the ignorance of otherwise intelligent men.

You want voodoo? Enter into the the field of biology and medicine, where two organisms react differently to identical stimulus.

It does seems odd that you view electricity with mystical awe, but still favor a more complex electrical device over simple points.

Cheers,

fletcha221 · « **Reply #22 on:** July 18, 2010, 12:59:51 PM »

two tired. I'm really being a little dramatic when it comes to electronics, it just seems to be what causes me the most trouble with every build I do. In retrospect I wish I just stayed with the points. I just liked the dyna because they don't require any adjusting. Outside of that, you raise very valid points, and correct ones. I'll keep you posted to my progress!

-Christian Fletcher

Mutany!

fletcha221 · « **Reply #23 on:** July 19, 2010, 07:41:26 PM »

OK EVERYONE......Here we go. Broke the POS tappet feeler i bought on EBAY. Anyone know where I can get a decent one(s)? Also, the manual I downloaded for my 550 here is missing a page, where it explains the full procedure....I think. I'll do some research when looking for the right tools.

Frostyboy · « **Reply #24 on:** July 19, 2010, 08:34:13 PM »

Quote from: fletcha221 on July 19, 2010, 07:41:26 PM

Also, the manual I downloaded for my 550 here is missing a page, where it explains the full procedure....I think.

This is available at the top of this forum, it has the entire procedure.
CB550 Owners Maintenance Manual 1974: http://www.mediafire.com/?j0mmwzqmgom

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Author Topic: 75 550k Advice (Read 2830 times)