Topic: Dad's 1978 Honda CB550k

[grcamna2]

okay, I think we all underestimated my incompetence with a multimeter... I did test voltage at the battery, just to make sure it was working. I get 13.1 volts, after having the battery on the tender for the last few days.

To test voltage to the coils, I turned the key to on, then connected the red probe to the yellow wire coming from the main harness. I tried connecting the black probe to both the black wire and the engine, and although the numbers bounce for a second, the meter lands on 0. Same with the blue wire. I have my multimeter set on "V- 20." Do I need to be hitting the start button to see voltage to the coils?

Then I tried to test resistance on the coils. I changed my multimeter to "ohms 20k" and connected the probes to the blue wire (or yellow)and the black wire with white stripe. Again numbers bounce for a second and then land on zero. I get a positive beep when I test for continuity, which I didn't think should happen.

I can't get any readings or continuity testing from one spark plug cap to another.

Am I goofing this up?

I'm just going to clean up all the rust on my grounds here at least!

The black wire coming from the harness is the + positive power wire.

[joegeis]

So do I just connect the red probe to the black wire and the black probe to ground, and that should read 12v with the key on? Do I need to be hitting the start button to get that reading?\

Also, after cleaning everything and putting it back together, the bike still does not start (to no surprise). I pulled the plugs after and they were not wet. Smelled faintly of gas, but they were dry. To recap:

* I do have spark
* Carbs, points and valve clearances recently cleaned, timed and gapped, but bike has not been started since
* Airbox boot fitment issue, boots now taped to carb
* Bike will fire up with starting fluid for a second

Does this sound more like a fuel issue? I'm thinking of taking the carbs back apart again and checking that nothing is blocked or stuck next.

[grcamna2]

So do I just connect the red probe to the black wire and the black probe to ground, and that should read 12v with the key on? Do I need to be hitting the start button to get that reading?\

Also, after cleaning everything and putting it back together, the bike still does not start (to no surprise). I pulled the plugs after and they were not wet. Smelled faintly of gas, but they were dry. To recap:

* I do have spark
* Carbs, points and valve clearances recently cleaned, timed and gapped, but bike has not been started since
* Airbox boot fitment issue, boots now taped to carb
* Bike will fire up with starting fluid for a second

Does this sound more like a fuel issue? I'm thinking of taking the carbs back apart again and checking that nothing is blocked or stuck next.

Considering what you said in this post,I'm leaning toward fuel issue..  are you sure all 4) of the carb. bowls are full ?

I find a bike will usually start better if you only open the throttle 'just a little' and hold it open 'just a hair' with the choke close to Full On,in certain situations..  imo. 
Would be much easier to check 'in person',rather than online;that's why I'm hoping a member close to you will stop by to check a couple things.

The ethanol fuel loses lots of it's kick(even in a week  )in a very short time;make sure you got Fresh Fuel in there.

[calj737]

You have a fuel issue plain and simple.

Before you start ripping apart your carbs, simply open the drain screw with the peacock on. Does fuel run out? Catch it in a clear jar and inspect it for gunk.

Do you have adequate fuel in the tank? Rap on the side of the carbs with the pet clock open with the handle of a screwdriver to dislodge anything that might be interfering with fuel flow.

[joegeis]

BREAKTHROUGH TODAY!

I drained the fuel from the carbs, which had no sediment, but was darker than apple juice, which is weird because the fuel in the aux tank was still very light. Granted the fuel in my can was at least 18 months old. So, I got fresh gas (87 octane w/ ethanol) and the bike fired right up with full choke on the first crank! After 30 secs the bike died, but it restarted with no choke and just a hair of throttle. I tried to steady the idle at 1800, but it kept wanting to walk up to 3000. Not sure if that is relevant before a carb sync. I let the bike idle for a few minutes, and evaluated each cylinder:

#1 - getting a good amount of smoke out of the exhaust. Steady 200 degrees at the header
#2 - no smoke, steady 200 degrees
#3 - no smoke, only about 130 degrees
#4 - no smoke, but 220+ degrees at the header

Not sure what any of this means (should I be worried about piston rings on #1), or if a good carb sync will clean up the issues. I've also heard that just getting the bike on the road and riding it clears up a lot of engine issues on bikes that have been sitting a while, so hopefully nothing to worry about too much here.

Tomorrow I'll take a stab at syncing the carbs. This model has #2 as the "reference" carb, which I understand should make the process easier. If that goes well, I'll throw the tank and seat on and take it for its first ride in 25 years

I also noticed a little a spot under the left front fork, it seems like it was leaking fork oil (bottom of fork was a little wet). Seems really strange because the bike hasn't moved in weeks. All the bolts were tight. Something to keep an eye on I suppose.

[calj737]

Sync the carbs, fuel it up, and ride it like you stole it.  Afterwards, commence any tuning issues needed.

[joegeis]

I think I did an okay job syncing the carbs. It took a while to get the hang of, and I chased the numbers around for a good while, but here you can see my start and end points. Even after syncing, I seem to have to "chase" a steady idle around with the idle screw, and it sometimes creeps up to 3k on its own. I've never had a bike with a carb before, so I'm not sure how finicky I should expect it to be, or if this will go away once the bike gets a few miles under it.

After syncing the carbs, I threw the tank and seat on and took it just to the end of the street and back. It kept wanting to die on me (wanted to idle way too low once I went into first gear I think?), and it did die on me as it rolled up the driveway and into the garage! Regardless, it felt amazing to actually get the thing underneath me after working on it the last few months! So, updated to do list:

* Figure out how to improve idle?
* Fork oil leak
* Replace headlight
* Clean up wiring (all lights except the brake light stopped working once I remounted the headlight bucket to the forks. I must have more grounding issues that I thought I had just resolved).
* Replace seat cover
* Adjust brakes (front felt soft and back has WAY too much travel (not actually sure this is adjustable, now that I think about it)
* Polish up tank and side covers
* I've got Hondaman's ignition and blade fuse box on order, so installing those when they arrive

And I think that's about it for now. I'm sure new issues will emerge to solve along the way, but so much progress has been made!

 

[grcamna2]

Will the bike maintain a steady idle speed(1500?)once it's warmed-up ?

[joegeis]

Will the bike maintain a steady idle speed(1500?)once it's warmed-up ?

I will test it more and report back. But after I set the sync and the bike was warm, it did hold a pretty steady idle, with an exception that when I would rev it, it would not come all the way back down to where it started, but would "stick" a couple hundred RPMs higher. I was doing a LOT of fiddling with the idle screw.

Also today, I found that my main 7 amp fuse was blown. This solved the problem I was having with not getting any power to the headlight, and a few other various electrical gremlins! Luckily the bike still had its spares in the fuse box, because Hondaman's replacement fuse box is still a few days away. Funny enough the headlight fuse was NOT blown. I'm getting 11.4 volts to the headlight, which is exactly what I'm getting at the fuse box. Seems like that's pretty solid, no?

I do still have one lingering electrical issue at the moment. Sometimes, my turn signals work correctly, but sometimes it seems like something is shorting out. Right now, the left turn signal switch causes the taillight and at least one indicator light to blink, instead of the turn signals themselves (the front left signal blinks VERY dimly). Tomorrow when I go out there it will probably work fine. Where could this issue be located? I have been through my left switch housing and all the connectors in the headlight bucket, and ensured everything was tight and connected correctly.

I also checked the fork again - more drips. Its not coming from the drain screw, and the bolts that hold the axle to the fork are wet, so it must be the screw up inside the bottom of the fork thats leaking somehow. Tomorrow I'll take the front tire off and try to snug it up.

[grcamna2]

Will the bike maintain a steady idle speed(1500?)once it's warmed-up ?

I will test it more and report back. But after I set the sync and the bike was warm, it did hold a pretty steady idle, with an exception that when I would rev it, it would not come all the way back down to where it started, but would "stick" a couple hundred RPMs higher. I was doing a LOT of fiddling with the idle screw.

Also today, I found that my main 7 amp fuse was blown. This solved the problem I was having with not getting any power to the headlight, and a few other various electrical gremlins! Luckily the bike still had its spares in the fuse box, because Hondaman's replacement fuse box is still a few days away. Funny enough the headlight fuse was NOT blown. I'm getting 11.4 volts to the headlight, which is exactly what I'm getting at the fuse box. Seems like that's pretty solid, no?

I do still have one lingering electrical issue at the moment. Sometimes, my turn signals work correctly, but sometimes it seems like something is shorting out. Right now, the left turn signal switch causes the taillight and at least one indicator light to blink, instead of the turn signals themselves (the front left signal blinks VERY dimly). Tomorrow when I go out there it will probably work fine. Where could this issue be located? I have been through my left switch housing and all the connectors in the headlight bucket, and ensured everything was tight and connected correctly.

I also checked the fork again - more drips. Its not coming from the drain screw, and the bolts that hold the axle to the fork are wet, so it must be the screw up inside the bottom of the fork thats leaking somehow. Tomorrow I'll take the front tire off and try to snug it up.

The bike has been sitting a while and you most likely have multiple 'grounding issues';the lights need to make a 'ground path' all the way from the battery - through the frame to all the lights,so it's a good idea to make sure each light has a solid 'earth/ground' connection,which may work from where the light mounts.
The green,etc. ground wires need to touch bare metal and connect to the frame;check all your frame ground-to-harness-connections along with cleaning each and every wire metal connector on the bike.

Did you take a look at your fork seals for leaks?

[joegeis]

just went back out and messed with the wires a little more, trying to aim the bucket down a bit. Tested the turn signals, and now everything works properly except the front left signal (which was fine 20 minutes ago). I'm still trying to fully understand how the wiring system works on this bike (I'm new to electronics at all), but if I have a good ground (evidenced by no drop in voltage on the headlight circuit, would it not also be good for the turn signals? They are grounded in the headlight bucket as well, right?

I did clean up the grounding point at the coils, but I believe there is another one near the battery that I can clean up. Are there any others that I should do? Or am I misunderstanding what you mean by frame ground to harness connections?

Appreciate all the help!

Oh, and the fork seals - I replaced those when I rebuilt the forks, I double checked, and there is no oil seeping through those seals and boots.

[calj737]

11.4v is way too low. You should be above 12.4v. Test the voltage directly at the battery. Compare that to other locations ( coils, headlight circuit, fuse block ((both sides of the fuse)). If you have more than 0.5v difference from the battery, then you have too much resistance along the way.

To remedy that, you need to do a meticulous cleaning of each and every connector, bullet connector, ground, and eliminate that drop. There is a ground from battery to the frame, right side, and it’s pinched between the motor, frame and bracket above your foot peg. Make sure the frame is bare metal, the bracket is bare metal, and the ground lug is super clean.

The bolt in the bottom of the shock connects to the damping rod. There is supposed to be a crush washer between the bolt and the slider. And that bolt needs to be torqued up pretty tight. The bolt is a bear to remove unless the shock is still assembled, but you may lose enough fluid that replenishing it is necessary. Start by solving the leak.

[Mark1976]

11.4v is way too low. You should be above 12.4v. Test the voltage directly at the battery. Compare that to other locations ( coils, headlight circuit, fuse block ((both sides of the fuse)). If you have more than 0.5v difference from the battery, then you have too much resistance along the way.

To remedy that, you need to do a meticulous cleaning of each and every connector, bullet connector, ground, and eliminate that drop. There is a ground from battery to the frame, right side, and it’s pinched between the motor, frame and bracket above your foot peg. Make sure the frame is bare metal, the bracket is bare metal, and the ground lug is super clean.

This very sound advice, poor and or dirty connections can and will be a source of never ending frustration. Do yourself a favor, check them all, it's time well spent. For me its literally one of the first things to do in this type of situation. The upgraded fuse box is a great investment. If you like to keep your points, Marks ignition upgrade is a great investment as well, never worry about your condensers again. I check my dwell and lube the pionts at the beginning of each season, takes 5 minutes, that's it.

[RAFster122s]

Spending an afternoon, or however long it takes you, going through your entire bike's harness cleaning all the connectors and your grounds is time well spent. A .177 caliber brass brush can help you clean the female connectors.

A tiny dab of dielectric grease for the connections on reassembly can help you have a longer electrical life before any issues reappear.
A brass toothbrush style works well for the male bullets. Wear gloves as your skin getting abraded holding the connectors can sometimes get irritated after an afternoon scrubbing the connectors. Ymmv on that need...

[joegeis]

Should I just start at the positive battery terminal and follow it all the way through, testing to confirm low voltage drop at each connection before moving on? I couldn't really find a good guide on how to tackle this.

I've got contact cleaner, scotch brite pads, brass brushes and dialectric grease, so I'll take a go at it today. Battery is on the charger, so I'll have a good battery voltage starting point.

Also, yes I have Mark's ignition mod arriving with the fuse box!

[grcamna2]

Take your time and clean-up all the male and female bullet connectors plus other electrical connections;electrical is the weakest system and needs this after sitting and getting corroded.

[calj737]

Wait until battery is fully charged, then unplug and let it rest for 2 hours. Take your reading there. Then go the fuse box. Measure voltage on the left side, then on right for the MAIN. Turn the key ON, then check the other circuits of the fuse box. Write these all down.

Proceed to the coils and check the voltage there (yellow and blue are the grounds for the blk/wht).

By now you should have located the drop somewhere or through a particular component that is central to the resistance drop.

[joegeis]

Cal, before I saw your note, I just decided to take the electrical panel apart and clean everything. It was in BAD shape. Take a look at the bottom photos here. After cleaning, shining and lightly greasing all connections, I no longer have any voltage drop, at least to the fuse box. My voltage drop to the headlight is still just as bad though. There is definitely more work to do. I have the bike back on the charger for now. It gets up to 12.6 after charging, but was down to 11.8 by the time I was done messing with it. I'll follow your guide below next.

What do you mean: "measure voltage on the left side, then on right for the main?" Do you mean the main 15 amp fuse?

[calj737]

Yes, measure the left side of the fuse, then the right side. This determines if there’s a drop through the fuse panel.

[BenelliSEI]

Notice that your headlight and front turn signals are all hanging from the “fork ears” that have rubber isolators (top and bottom) where they sit on the fork tubes. Everything must be connected to a good ground (green wires in the bucket) to work properly…..

[joegeis]

Okay, took those measurements:

Bike off:
Battery Voltage 12.74
Main Left: 12.74
Main Right: 12.74

Bike on:
Battery Voltage: 12.14
7am Tail: 11.00 / 10.90
7amp Head: 10.96 / 10.96
Main: 11.60 / 11.60

For some reason I can't get a reading at the coils. I have key on, switch to run, red probe in black female bullet connector housing that each coil plugs into and I tried the black probe on the engine, the yellow and blue connectors. Nada.

[joegeis]

Hondaman's parts and my new seat cover arrived today! I went with the gumtwo cover, but I am sad it doesn't say HONDA on the back. I'm going to wait to tackle the ignition until I have my voltage drop situation fixed though.

When removing my seat, one of the screws for the passenger strap has completely fused to the nut under the seat. I had to drill the screw head out to remove the strap. I still cannot in any way get the rest of the screw out. Of all the stuck bolts and bearings I've dealt with on this bike, I can't believe this is the one that got me. I'm not sure what I'm going to do. I guess just not reinstall a strap at the moment? Really frustrated!

[newday777]

Did you pull the hitch pin clip off the screw on the back side of the seat before unscrewing the strap screw?

[calj737]

Okay, took those measurements:

Bike off:
Battery Voltage 12.74
Main Left: 12.74
Main Right: 12.74

Bike on:
Battery Voltage: 12.14
7am Tail: 11.00 / 10.90
7amp Head: 10.96 / 10.96
Main: 11.60 / 11.60

For some reason I can't get a reading at the coils. I have key on, switch to run, red probe in black female bullet connector housing that each coil plugs into and I tried the black probe on the engine, the yellow and blue connectors. Nada.

Is the KILL switch set to RUN? If not, the BLK/WHT wire won’t have power.

The drop from 12.14 to 11.60 is expected (0.5v is common). What IS problematic is the voltage at your battery is only 12.14. That’s low. It should be higher.

The headlamp fuse could be a case of poor grounds in the bucket as Benelli mentioned. Wherever you have the light grounded, run your probes from that point to the motor with your meter set to Ohms. What’s the reading? A poor ground can create a loss as well the backside of the fuse block may be heavily oxidized and in need of attention.

[joegeis]

Did you pull the hitch pin clip off the screw on the back side of the seat before unscrewing the strap screw?

lol, yes