Topic: Dad's 1978 Honda CB550k

[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.

[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.

[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.

[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?

[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?

[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

[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.

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.

I'm headed out of town for 24 hours. I'll put it back on the trickle charger while I'm gone and see how it looks after.

I did reconnect and retighten the grounding bolts on the headlamp housing since the last pictures were taken. Can I test the quality of the ground in the headlight bucket by taking the voltage reading of the headlight positive while grounding the probe on the engine and compare that to the voltage drop when grounding in the bucket? Does that make sense?

[joegeis]

only got to work on the bike briefly today, but I got that damn passenger strap bolt out. I drilled it through and cleaned the bits out and then ran an M6 tap through to clean up any damage to the threads. Good as new! Now I need to pick up a replacement machine screw. I'll probably put a nylon lock nut on the end since I won't be able to reuse the cotter pin on a replacement screw.

Also, I unplugged the battery tender this morning, and checked the battery voltage this evening. Granted it was more than 2 hours, but it did get a solid 48 hours of time on the charger. It was reading 13.14 volts. It is a new AGM battery. Is that fine?

My Hella headlight housing arrived today too, so that is exciting! We're getting close to being on the road

[joegeis]

Okay, new measurements this evening:

Bike off:
Battery Voltage 13.16
Main Left: 13.16
Main Right: 13.16

Bike on:
Battery Voltage: 12.14
7am Tail: 11.50 / 11.39
7amp Head: 11.55 / 11.54
Main: 12.05 / 12.25

Coils: 11.58
Headlight 11.56

Resistance from the grounding bundle in the headlight bucket to the engine bounces from 0.5-3.0 ohms.

Also got my seat recovered tonight. My foam was in great shape, the gumtwo cover was very nice, and I still had the chrome trim which was easy to reinstall. I need to go pick up a screw to replace the one I had to drill out, and then I can put the passenger strap back on and the seat will be complete!

[joegeis]

okay, so I'm using some alligator clips to the engine to get a more consistent reading. Resistance from the headlight grounding wire to the engine is 0.6 ohms with the bike off, but jumps to 16 ohms with the bike on.

I'm going to trace grounding wires and clean up connections tonight. What else should I be doing? Where else might I be seeing voltage drop?

-update - I cleaned up the grounding wires for the tail light section. I inspected the frame grounding point by the rear brake switch. It seems in good order. No rust or corrosion. I am not reallying seeing any remaining grounding connections to clean up. I've done everything in the headlight bucket, everything on the side panel, the grounding point and all connections at the coils and the connector under the seat going to the tail.

[joegeis]

So with only a few niggling things remaining for now, I really wanted to test ride the bike, so I put the old headlight back in and put everything else back together. I had some funny idle behavior and sounds that cleared up once the engine was warm. I rode about a half mile through the neighborhood getting up to third gear. Because I have no experience on vintage bikes, it hard for me to gauge what feels "right," because EVERYTHING feels so much different from my 2018 MT07! Tomorrow I'll ride it up to the gas station to fill the tank (its on fumes right now) and try to get a few more miles on it and push the speed and rpms higher and report back.

All that said, this was a monumental day! I'm so happy to have gotten the bike back into this condition, and I really can't wait to have it A+ reliable and ready to daily. I'm sure Dad is happy the bike is back on the road too. Thanks for all the help getting this far, guys!

First ride:
https://photos.app.goo.gl/wpe6oPhgZ1A3xgmS6

Strange idle:
https://photos.app.goo.gl/xoav6iuv3UT9oA7J9

Walk around:
https://photos.app.goo.gl/fJAEcrNwgvjV2a3N9

[grcamna2]

Good to hear you got your bike out on the road 

[joegeis]

Please don’t hesitate to rev the engine. 4,000 RPMs is on the low end, most run these motors well above 6,000. That’s where they are happiest. Promise.

Yes Sir!

[joegeis]

I put about 2 gallons in the tank and was letting the bike warm up today and realized gas was pouring out of carbs 2 & 3 whenever the petcock was on. Shut the petcock off, leak stops, turn it on and a few seconds later gas leak. I understand this can be related to stuck floats, so i took the carbs off and dropped the bowls on 2&3. Everything looks fine to me. pins and hinges are smooth, no sediment in the bowls. I sprayed them out with carb cleaner, but is there anything else I can do before putting them back in and trying again? I have new floats I can throw on, but these seem fine...

Take a look at the last few photos in the album. https://photos.app.goo.gl/yqMD7iLYyYHFVBuo7

Also, now I can't get these bowl gaskets to fit! Does carb cleaner make them expand or something? They are brand new, but seem to have expanded and don't want to sit in the groove!

[joegeis]

When I rapped on the carb bodies, it actually caused more fuel to leak out!

------

update - so I leak tested the bowls, and had no leaks, so thats good news. I did open up carbs 1 & 4 just to see, and there was some evidence of rust and sediment. I sprayed each carb out with carb cleaner and compressed air and verified that the bowls and needles were operating properly. When I drained some gas from the tank to test the bowls, 2 little bits of sediment came too. The tank looked PRISTINE inside, so I never did more than empty and refill it. I think I'll throw an inline filter on for the first few tanks of gas, or until it runs clear.

Somehow I lost a seat hinge pin today while messing with the carbs. I can't find the damn thing anywhere, so I guess I'll be picking up a pin at the parts store along with a fuel filter!

Oh, and since I had the carbs off, I had the opportunity to replace the airbox boots with Paul's homemade ones. They were a good 1/4 to 1/2 inch longer than what was on my bike, and fit great! As a bonus, they are much more pliable and make it just a little easier to put the carbs back on. No more rubber tape!

hopefully tomorrow I'll be able to stretch the bike's legs properly!