Topic: Hello, all. New here with 1975 CB550 problems

[JimZ]

This is my first bike, a 1975 CB550. I have a couple buddies that know bikes, but neither ride a Honda. I have a few problems that we can't figure out.

First is the noise. I adjusted the valves twice. They are perfect. The second time was just to see if I messed up on the first time. I didn't. They are perfect. I changed the the oil and filter. The oil is topped off. So the noise... when it's running I'm getting a serious sewing machine tic coming from the valves. During the second valve adjustment I realized what it was. When carb 1 is at tdc, the rocker arms on all adjustable valves have side to side play. When you wiggle them side to side, they make the sewing machine sound I hear when it's running. When 4 is at tdc, same deal. Rocker arms have side to side play. Even when the bike is hot, the sound persists.

I took it out last night and while it was hot, it died on me. The oil and neutral lights were fading (which is the second problem I'll get to). It wouldn't crank on a kick or running pop. I pushed it 8 blocks home. After about 30 minutes of griping, I tested the battery and got 11.75 volts. And it started on the first kick.

One buddy said dying when it's hot sounds like a valve train issue, which brings me back to those loose rocker arms.

Problem 2. Earlier in the night I started it up and held it at 2 grand to get it warm. Reason being I'm firing on 3 cylinders until it warms up a little. Otherwise she craps out. Something sticking a float bowl, pulling carbs is coming up. I held it at 2 grand for a good long while at full choke, let off the throttle, and she immediately fell on her face and the battery was dead. Charged the battery up to almost 70%, put my gear on, fired it up on the first kick and rode away. Turned the choke off after three blocks. At every stop it felt like it was gonna die. Got to the pizza place I was heading to, and it finally died as I took a RIGHT (I'll get to this) to park. Came outside feeling pessimistic, but it fired up on the first kick. Rode 3 blocks and it died approaching a stop sign. Yes, petcock was open. It was pretty hot by then. Fading oil and neutral lights, not starting no matter how much I was killing myself trying to kick it and running pop it. Then pushed it the rest of the way home. And like I said, after 30 minutes, tested the battery and fired it up on the first kick with full choke. I immediately let off the throttle and she sat there idling just fine, albeit the sewing machine sound. I turned the bars to the left, fine. I turned the bars to the right, and she immediately died. So I have a bad connection somewhere.

My questions are: What's up with the rocker arms? Is that a normal old Honda sound, or is it a fix immediately it's killing your bike sound? And how about the battery dying? It's a brand new battery and seems to die and come back to life on a whim. Thought about charging it to 100%, riding for a couple hours, then seeing if it's holding a charge, but not if the loose rocker arms are bad to ride on. Finally, what about this electrical problem? Before going through everything to find the culprit, any idea what to single out that would cause it to shut off when turning the bars to the right?

I thank you in advance for your expertise. It's getting nice outside. I just want to be on it and not have to wonder if it's gonna die a few blocks from the garage.

Jim

[phil71]

rockers will have some side to side play. Make sure you're setting them for a tight slip fit cold. Meaning the next size up feeler gauge wont slide thru.
  You have a rectifier or regulator failing.. best to just put a modern combined reg/rect and be done with it forever.
The battery when it sits recovers some voltage, which is why it'll kick after sitting awhile. That's a sign of a healthy battery. It wont stay healthy if you keep cycling it that dead all the time.

[Steve_K]

Welcome to the forum!

Have you done a tune up?  That would include oil and filter change, adjust values and cam chain.
Check and adjust ignition timing.  Check that the carbs are adjusted(balanced).

Down load the manual for the tune up procedures and the  engine may very well run smoother and not have that rattle you have.

The manual will give you the steps to check your charging system.

A 550 needs to keep the revs up.  I recall that for it to charge the battery, the revs need to be above  3500 rpms. 

Ask questions and read the manual and you get her running just fine.
Steve

[Bailgang]

Whether it's normal or not my 75 550 is as noisy as can be, replacing the primary chain helped but it still clatters like a sewing machine up on the valve train and is noisier when at operating temp. My guess and this is only a guess is that the early 550 have floating rocker arm shafts which from what I'm told is good for HP but make a noisy engine. Also out of sync carbs can make an engine noisy as well. What I will say is that as noisy as my 550 has been and still is it's been running reliably since I first put it back together 4 years ago. The sewing machine noise is a nuisance but I deal with it.

[Stev-o]

First off, welcome. My '76 550 is noisy too, depending on the level, can be considered "normal". If you could post a video, we'd have a better idea.  As said, carb syncing can help.

Sounds like you have two possible other issues: dirty carbs and charging problem/battery.
With the bike running, put a volt meter on your battery at idle, note voltage. Then hold at 3000 fast idle, voltage should climb if charging. 

Second issue, carbs. Sounds like they need a good cleaning and rebuild. Your idle jets could be plugged, a good rebuild kit will include new jets. My bike won't run good with full choke and don't think it should.  When tuned correctly, the 550's are a blast to ride! I have a couple 750's and still love to ride my 550.

We're here to help, you'll get there.

[JimZ]

Hello all. So, I resolved one issue. The battery losing charge isn't due to any regulator/rectifier problem. It's due to the fact that I just learned how to ride a motorcycle and all I've been doing is putting around the block. Finally went for a longer ride and got it up to speed the whole time. Came back and battery was all good. Still is.

The crappy idle and stalling before hot, and maybe some of the noise - I'm pretty convinced will be resolved after I clean the carbs. One question here. It runs well when I'm riding. I know there's something sticking in #3's float bowl - the PO told me, and the gas stains in the garage make it pretty obvious. So... Since I'm pulling the carbs anyway, do I get a rebuild kit and do all 4, even though it's running well? Or do I just clean out the leaking one? I'll open them all up and see what they look like, but the PO said he cleaned them (didn't rebuild, just cleaned) right before I bought it. He just missed something in #3. It seems like rebuilding is fixing something that ain't broke and opening another can of worms, but again, I'm a newbie. Also, I'm kinda broke after buying the bike, helmet, etc...

The 3rd issue is the bike dying when I turn the bars hard right, which is really weird. The wiring diagram in my Haynes manual gives me a headache. I don't own a magnifying glass and I have no idea where to start. Also, my crappy computer has a tiny screen and the google images of color diagrams are blurry and impossible to read. Any advice or direction to a previous post would be awesome. I'm assuming it has to do with either the ignition or the kill switch. The bundle of wires coming from the kill switch is encased in plastic. The bundle of wires coming from the ignition is wrapped in electic tape. And it's only when I turn hard right, and even with my assumption that the problem is in one of those bundles, I still have no idea where to begin.

That aside, my first long-ish ride going sorta fast was incredible. I've wanted a bike for so long, and it's totally living up to my expectations. 

[Duanob]

Have you done a full 3000 mile tune up and then a carb sync? The lack of the carbs being in sync can cause a lot of noise on these engines. If all cylinders are not synced they pretty much fight against each other at idle. There is no primary chain tensioner so the carbs must be synced pretty close to run smooth.

Also have you adjusted your cam chain? There is a slotted stud with a #10 nut just below the carbs coming out of the jugs. there are several way of adjusting it. rotate your motor until it's 15 degrees past the 1/4 T mark on the timing plate. Loosen the nut on the tensioner. Carefully turn the slotted screw counterclockwise and tighten the nut. That's how I do it. there are other ways.

if you have excessive side to side play on your rocker arms you may have a worn out cam cover. Common problem in the older 550 motors. They made a newer version of the cam cover to prevent the arms from wearing out prematurely. See below. Notice the four extra 4 extra studs in the center sump area. Also notice the rubber band trick to installing a cam cover. You can screw things up bad if you don't follow the proper procedure. Its in the manual.

BUT, even with all that, my 550 is still a bit noisey, just a nature of the beast.

[dave500]

dont listen to your friends who know bikes,,if they are telling you you have a valve train issue because it cuts out when its hot theyll also tell you your cam shaft might be 180 degrees out?the side slack on the rockers is normal and dosent create much noise,adjust your cam chain,then after setting the ignition to stock specs(this is where your friends who know bikes can help?)the carbs should be vacuum synced.

[Steve_K]

On the wiring diagram,  I went to a copy shop and had mine blown up, to either 2 or 3 times.    It also gives you room to make notes.  I wired new controls and head light relays and it made it much easier.
Steve

[LesterPiglet]

Using the choke for 3 blocks is excessive. I can turn off the choke before my bike is out of the garage. Clean those carbs out.

[JimZ]

Duanob- I did adjust the cam chain, in the same way you described. Not having the manual in front of me, I'm not sure if I've done everything in the 3000 mile tune up. I've adjusted the valves, cam chain, and changed oil and filter. A motorcycle mechanic aquaintance said the same thing... Look at the recommended maintenance in the manual and do it all. As far as the cam cover goes, I tried to pull it off to see what's what with the noise but, shockingly (yeah right), all the screws are seized. So down the line a new cover may be in order. I'll need it anyway once i drill out all the screws.

Everyone- Cleaning the carbs is coming right up. But again, go ahead and buy the rebuild kit or just clean them out? The PO brought the bike back from the cafe-in-the-making dead. Made a non running bike run, and brought it back to almost stock. He had 7 other bikes in his garage. Two Triumphs, two Nortons, a CB750, etc... all old and all stock. He cares about the stuff, I trust that he cleaned the carbs. So buy the kit or just re-clean the leaking one and get them synched? I don't know if if he synched them.

Also, the pipes aren't stock. Maybe the carbs need to be synched to these new Hooker pipes?

Steve_K- good advice. I'll do that. I'm gonna assume that my loose connection is in the gnarly electric tape bundle. I'll start there.

Thanks everyone.

[xsmooth69x]

Have you done a full 3000 mile tune up and then a carb sync? The lack of the carbs being in sync can cause a lot of noise on these engines. If all cylinders are not synced they pretty much fight against each other at idle. There is no primary chain tensioner so the carbs must be synced pretty close to run smooth.

Also have you adjusted your cam chain? There is a slotted stud with a #10 nut just below the carbs coming out of the jugs. there are several way of adjusting it. rotate your motor until it's 15 degrees past the 1/4 T mark on the timing plate. Loosen the nut on the tensioner. Carefully turn the slotted screw counterclockwise and tighten the nut. That's how I do it. there are other ways.

if you have excessive side to side play on your rocker arms you may have a worn out cam cover. Common problem in the older 550 motors. They made a newer version of the cam cover to prevent the arms from wearing out prematurely. See below. Notice the four extra 4 extra studs in the center sump area. Also notice the rubber band trick to installing a cam cover. You can screw things up bad if you don't follow the proper procedure. Its in the manual.

BUT, even with all that, my 550 is still a bit noisey, just a nature of the beast.

that rubber band trick is genius!!!!

[bjbuchanan]

The sync is to make sure that you get equal vacuum from four different chambers. It is a way to work something mechanical in sync with each other which anyone who has done some mech/electro stuff is a pain without programming

It is simple it is just not how you are thinking about it. Exhaust, intake, stuff like that doesn't affect the sync. It affects airflow in/out, the engine is an airpumper. Slide position through jet needle adjustments and actual slide height is what the sync fixes or seeks to anyway

You run too much choke. Get it warmed up to where it doesn't want the choke anymore to run and turn choke totally off. Then run for a bit to get it nice and warm and see where your idle is at. You want idle around 1200 and set it hot, not warm, not at startup, but hot, like when you are cruising along and have to stop at a light. That would be when that too low idle rears its head and you look like a clown and have to pull off to the side of the road

We all have the friend who doesn't know what he is talking about, and your valvetrain guy is him. I would take any of those suggestions with a grain of salt.

Common consensus, myself included is to keep all your stock brass parts and just replace rubber stuff and float needle/seat if it is older/aged/leaking. Cheaper this way and most carb kits the quality is just not there compared to stock

Post up a pic, lets see it. You gotta have five posts by now so put up a pic. Host to photobucket and it auto resizes

[Duanob]

If the carbs have been torn into recently then just buy gasket kits for now. Lots cheaper but you will probably need some new bowl gaskets, and the o-rings can get brittle and crack. Its always nice to see how everything works such as the slides, the floats, the float needles, etc. Go easy on the leaf springs the hold the main jets in they are easy to break and hard to find. And make sure the floats don't get caught up or stuck when assembling the bowls back on the carbs.

[JimZ]

Thanks for the advice. I'll look for the gasket kit on eBay or something. Once I've pulled them, cleaned them, and put them back together, I'm probably gonna bring them to one of the local vintage bike shops to get them synched. I watched a video on how to do it, but it seems kind of above me right now.

In other news, I just picked up my girlfriend's new '72 cb175. Adorable.  and I'm sure there'll be questions to come about that, too.

Thanks again, guys.
Jim

[RAFster122s]

While it might be tempting to "fix" only the problem carb, it is a false economy to only mess with the one carb cleaning it. A good through clean of the carb passages and jets is needed to ensure you aren't chasing your tail on misdiagnosis.  Then, bench sync and when on bike vac sync.

Drilling heads off screws may not be necessary, an impact driver and properly fitted driver bit along with a good penetrating oil & some heat may be all that is needed.

Don't use after market jets as they just cause problems it has been shown. Their quality is sporadic and it leads to odd running issues that are hard to isolate. Keihin jets will have the logo on them.