Topic: new project 77 CB550

[DaveBarbier]

Static timing with a test light is good to get you in the ball park, but to verify the advance timing you need to use a strobe.

Regarding air leaks, check with propane or carb cleaner where the intake manifolds attach to the head. There are o-rings there that could be hard and cracked.

Have you removed the plugs and looked at the color after a relatively long idle with a fan blowing on the motor? If not, post a picture of them in 1>4 order.

[mitch5069]

Static timing with a test light is good to get you in the ball park, but to verify the advance timing you need to use a strobe.

Regarding air leaks, check with propane or carb cleaner where the intake manifolds attach to the head. There are o-rings there that could be hard and cracked.

Have you removed the plugs and looked at the color after a relatively long idle with a fan blowing on the motor? If not, post a picture of them in 1>4 order.

I have checked several times with propane and carb cleaner. the engine only seems to rev higher when I put the propane up to the uni pod foam which makes sense. As for the plugs I have not removed them yet. It's been a bit since I last posted but I did make the move into a house and that seems to consume most of my time. Currently working on get the garage set up as a shop to start working on this bike again. Any way I did ride the bike from my old apartment to my house and it ran but idled at around 4k any lower it seemed like it wanted to die on me. I should also note that to start it I had to jump the starter solenoid with a screw driver. I assumed the solenoid was bad so I got on off ebay and installed it. I didnt know what side was positive and what side was negative and since it didnt seem to be called out I assumed there was no polarity to it. Please let me know if that was a bad assumption. Anyway after I installed it I tried the start switch and nothing. Well almost nothing, the bike doesnt crank over nor could I hear the solenoid do anything but the headlight did dim... now I'm scratching my head on this one. Any advice is greatly appreciated. I'm starting to look at a wire diagram now but I cant see what could be wrong with it since the light is dimming ...

Thanks in advance

[DaveBarbier]

Correct, no polarity on the starter solenoid.

That sounds like the battery is low on charge. I'd check voltage with a meter then put it on a charger.

Regarding the high idle, that's usually because of air leaks (I know you've checked ) but could also be from a gummed up advancer mechanism. Do you have a timing strobe? You should verify that the advance comes in at around 3k rpm and that it hits between the double marks in the window.

So just to confirm, you did the full 3k mile service? Valve adjustment, cam chain, point gap, static timing, etc?

I read that you changed the needle height. Did you bench sync after that? It must be done when changing needle height. After bench syncing, you must vacuum sync. An out of sync bike can also have high idle issues. But in the service, syncing is always the last thing to be done as it is dependent on everything else.

I would pull plugs and verify gap, verify tappet clearance, cam chain, point gap and static timing again, then dynamic timing with strobe, and then sync the carbs.

[mitch5069]

I did just put a new battery in the bike and it turns the engine over without a struggle when I jump the solenoid terminals. I will check the voltage but I'm not putting my cards on it.

I only have a timing light not a strobe. Where is the advancer mechanism located? Is it by the points?

I am 90% sure I did all of the 3k service (it was over a month ago at this point) but I am sure I did not do anything with the cam chain. I did check the valve clearances, cleaned the carbs, checked the points gap, vacuum sync'd the carbs,  I will take a look at the manual and see what I need to do with that.

As far as changing the needle height: I changed the needle height down one clip setting to make the needle sit higher thinking my high idle was because it was running lean. After that didn't work I put it back on the original setting then vacuum sync'd the carbs. and that is where I am today on it.

I have off work today so I might go try to fire it up again and see what I can learn.

[DaveBarbier]

The advanced mech is behind the points plate. It's two pivoting weights with springs. As the bike's RPM increases, centrifugal force throws the weights out and that advances the timing by rotating the cam that the points glide on.

Some times that can be really gummed up and either won't let the bike get to full advance, or won't let it return back down.

It's not good to be only 90% sure you completed the 3k mile service. You should be 100%.

[mitch5069]

Ok that makes sense for the advancer mech.

suppose the advancer mech is gummed up in one of the scenarios you described, how would I clean this? Do I take the points off and clean with some type of solvent? I assume you can visually see if the advancer won't return back?

I do not have access to a strobe light so I am trying to figure out if I can check to see if this is truely a problem.

[DaveBarbier]

You'll see that it'll be gummed up, but taking it off and cleaning it can't hurt if you're in there. Just be aware how it goes together, the cam can be installed 180° out which is incorrect. There are faint marks for orientation. I think a hash mark on the cam and you line that up with the logo.

Also, you can get strobe timing lights for under $22 on eBay

Still not sure if this will solve your problem, but it's worth checking out.

[mitch5069]

Alright so ended up buying new boots to go from the carbs to the intake manifolds to try to eliminate that as a possible leak even though it passed the leak test with propane. When replacing these I found that the intake manifold on one side was not fully secured. I removed those and replace the o-rings for the manifolds then the connecting boots and got it to idle at around 1200 to 1400 rpms. I took it for a couple mile ride and I decided to open up  the throttle past 4k and the bike died. The main fuse went. So I ran to autozone and picked up some more fuses and kept burning them up on the way home. When I got home I had it running and I could watch the fuse burn up as I rev'd the engine high.

Anyone have an idea what would cause that? Would that be an issue with the regulator? I know the PO hand hooked the terminals up backwards and tried to jump it once could this have fried my regulator and the starter solenoid?

[DaveBarbier]

Could be a regulator issue. Does it blow the fuse when your just revving it up and not moving? Hook up your volt meter to the battery and record the voltage readings as you increase RPMs. Note voltage of battery at idle, too.

Does your headlight glow brighter as you climb up in RPMs?

Is your RPM issue fixed?

[calj737]

I know the PO hand hooked the terminals up backwards and tried to jump it once could this have fried my regulator Yes, possible. And/or the Rectifier.

and the starter solenoid? Not involved in charging, and not likely damaged.

You should grab a multimeter and test your Regulator and Rectifier independently to confirm they're both good. If your bike is charging normally, I'd suspect that you have a loose BLACK wire (these are switched 12v with key ON) that is shorting out somewhere. Is your stock harness somewhat, "hacked up" by a Previous Owner? If so, best to remove the tank, and side panels, pull the headlight bulb, and get to work cleaning and repairing any "shade tree fixes". 

[mitch5069]

to DaveBarbier:
yes it idles fine but when I rev it at a stand still the fuse blows, not immediately but a few cracks of the throttle.

yes the headlight does seem to get a bit brighter when I rev the engine but I feel like I've seen this on several bikes i've owned and the idling issue seems to be fixed.

to Calj7373
How to I test the regulator? I looked online at http://manuals.sohc4.net/cb550/ under Part 4: Electrical and it didnt really give me any information (well I didn't exactly understand what it was asking me to do). So to answer another question the wire harness is stock but I did take a closer look at it and found that there was some copper exposed on the green wire coming back the harness. I put pictures below.

Some other information I noted last night:
bat voltage with key off = 11.93V
bat voltage at idle = about the same
reving the engine (maybe up to 5Kish) = never above 12V
Per he service manual at the link I posted above I reviewed the regulator and found that the core gap was about .035" which is within spec and the point gap was much less than .008" (.008 is what it should be set at per the manual) and looked to be fouled. I buffed the points with 600 grit sand paper and set the gap to .008". I reinstalled the regulator on the bike and started it up again. With the 15A main fuse in I could rev the engine and watch it smoke and bow in the tube.

Note: all battery measurements were taken before I adjusted the regulator. Not sure if that matters or not.

Is this pointing me in the direction of the rectifier? Shouldn't the batter voltage go up around 14V when reving into the charging zone?
I guess I should take the wiring harness out and look for it shorted to another wire???

[calj737]

The rectifier converts AC to DC, so I doubt that is your issue unless a diode is leaking and you are observing too high an AC voltage at the battery.

A couple of things:
- 11.93v with key OFF is a too low battery voltage. Charge your battery fully. Let rest 2 hours. Then retake the voltage reading at the battery.

- Glowing fuses in the panel is an indication of resistance. The fuse block itself needs maintenance. Remove it from the bike. Clean the brass connectors shiny clean, and flip the box over and tend to the backside also. This is a common location for corrosion and neglect. OR, replace it with an ATC blade fuse type and solve the issue there.

- Here's a link to how I troubleshoot each electrical component on my bikes:
http://www.electrosport.com/media/pdf/fault-finding-diagram.pdf
Take it step-by-step to identify exactly which component(s) are in need or service or replacement.


All electrical diagnosis MUST begin with a "known good" battery. Even if you bought the battery recently, its always possible that after full discharge and recharge it can be weak. Get that verified before proceeding. And lastly, it is very likely that every connector, ground, and switch needs a decent cleaning. Its a maintenance thing that has probably never been done. Its tedious, but not difficult. Its time consuming, but cheap. Its necessary, but seldom done by new owners. And its NEVER done by Previous Owners before selling these older bikes 

[mitch5069]

So last night I took a look at the wire harness and found that the green exposed wire was not shorted to anything else. I retaped over the exposed wires and then cleaned the terminals on the fuse block and I left the battery on charge overnight. This morning the charger was off so the battery was fully charged. I waited a few hours and started it up again. With the multimeter hooked up the the battery terminals a rev'd the engine to around 5K and saw the multimeter jump to into 16 volts and the the fuse went out. Maybe I do have a faulty regulator after all. I will follow the troubleshooting guide and keep everyone posted. Might end up going down the path of a regulator/rectifer all in one. Any thoughts on one of these?

[calj737]

Do pay attention to any AC voltage readings found at the battery too. That would indicate a rectifier fault. If your regulator is misbehaving, or can adjust it on these bikes, though not often needed.

It is far more likely that you have a bad connection through the regulator (especially the BLACK wire) that monitors the battery voltage status.

Modern solid state Reg/Recs are very popular, as are the replacement individual units from Oregon. Either are great choices if your are bust.

[mitch5069]

I haven't had a chance to check the black wire from the regulator but I did look at a schematic and had a question. I used the schematic in the link below and I noticed that the black wire goes to something called the "starter magnetic switch", what is this? is that just the push button on the right control? When I am comparing the voltage on the battery to the voltage going to the regulator what wires should I be checking? The black to the white wire?

http://oldmanhonda.com/MC/WiringDiagrams/CB550.jpg

[calj737]

Solenoid. Use the link I posted earlier to check your components and charging system.

[mitch5069]

So I dug into this a little more and checked some voltages and they are as follows:

battery voltage (with the key on) = 11.88
Voltage to red connection on solenoid = 11.84
voltage to yellow with red stripe wire going to solenoid (with starter switch pressed) - 11.38
Voltage to black wire on fuse block (7A fuse) = 10.54
Voltage to black wire on regulator 11.02
Voltage to black wire on turn signal relay = 11.05

one thing I did find very odd is there looks to be a large green resistor on the regulator that was very hot when I was checking voltages. I would like to note that I did not start the bike to get these voltages only had the key on.

Do these values seem normal to you guys? I think the trouble shooting guide says check voltage across battery and compare it to the voltage to the black wire on the RR which I assume is the regulator since there is no black wires on the rectifier. Is it normal for the resistor on the regulator to get hot? when I say hot I mean you can only keep your finger on it for a second before it is too hot to handle.

[calj737]

First off, your battery voltage is very low. You can not accurately diagnose anything with a battery at 11.88v.

The regulator being very hot is worrisome, but you need to start with a fully and freshly charged battery.