Topic: Dad's 1978 Honda CB550k

[newday777]

Once the Evaporust settles to the bottom of the bucket in the diesel fuel, I carefully bucket out the good fuel back into a fuel can to use another time.

Evapo-Rust The Original Super Safe Rust Remover, Water-based, Non-Toxic, Biodegradable, 5 Gallons https://a.co/d/cx5ldqs

[joegeis]

I fully drained the tank and put in the 1 gallon of evaporust that I had on hand. I sloshed it around really well. I'll let the tank sit normally for a few hours and then flip it upside down overnight.

Only a couple more tiny pieces of sediment came out, so I'm hopeful it's not a bad situation.

I'll drain the evaporust tomorrow and see how it looks. I'll probably just rinse with gasoline since I have it on hand.

[newday777]

I fully drained the tank and put in the 1 gallon of evaporust that I had on hand. I sloshed it around really well. I'll let the tank sit normally for a few hours and then flip it upside down overnight.

Only a couple more tiny pieces of sediment came out, so I'm hopeful it's not a bad situation.

I'll drain the evaporust tomorrow and see how it looks. I'll probably just rinse with gasoline since I have it on hand.

It has to be full to do the full soak.......

[calj737]

Stand your tank on end for a day (prop and protect it from falling). Then swap end for end and repeat. 1 gallon might just be enough to get the top in this orientation.

Fuel that evaporates collects on the underside of the top because we only ever fill our tanks for a short time. That “air space” is where rust forms first. The rust that is created in the bottom of the tank is from separated fuel left sitting for prolonged periods or mostly empty tanks sitting for long periods.

[grcamna2]

I fully drained the tank and put in the 1 gallon of evaporust that I had on hand. I sloshed it around really well. I'll let the tank sit normally for a few hours and then flip it upside down overnight.

Only a couple more tiny pieces of sediment came out, so I'm hopeful it's not a bad situation.

I'll drain the evaporust tomorrow and see how it looks. I'll probably just rinse with gasoline since I have it on hand.

It has to be full to do the full soak.......

+1

[joegeis]

The tank was put in storage full, I believe with ethanol free gas. That makes sense about the top being most likely location for rust to form. I'll flip the tank and soak the top.

[newday777]

The tank was put in storage full, I believe with ethanol free gas. That makes sense about the top being most likely location for rust to form. I'll flip the tank and soak the top.

It'll run out the vent.

[joegeis]

The tank was put in storage full, I believe with ethanol free gas. That makes sense about the top being most likely location for rust to form. I'll flip the tank and soak the top.

It'll run out the vent.

HA, yeah, I just learned that the hard way! Lost a few ounces before I realized it   

I'll lean it on its different sides and keep sloshing it around.

[joegeis]

I was looking for a sock filter / strainer for my petcock, and I think maybe the one I have is off a CB750. The one I have looks like this. Because it is riveted, I believe it is not rebuildable. It is working fine, but I can see that the o ring is pretty squishy and there was no strainer on the straw, and I'm not sure which parts will fit this one.
Is something like this going to fit?

[grcamna2]

I was looking for a sock filter / strainer for my petcock, and I think maybe the one I have is off a CB750. The one I have looks like this. Because it is riveted, I believe it is not rebuildable. It is working fine, but I can see that the o ring is pretty squishy and there was no strainer on the straw, and I'm not sure which parts will fit this one.
Is something like this going to fit?

I like the OEM Honda fuel petcock best. I usually 'go on a hunt' for an NOS or good used part to replace what's missing;part numbers are good to locate the ones you need. The filter screen is #16952-388-005 and it includes the rubber seal.

[joegeis]

Okay! I drained and rinsed the tank today. There was some rust "powder" and a few small pieces that came out. I used gasoline to rinse the tank a few times. I did this until I got no more sediment whatsoever. I then filled the tank with fresh fuel and the carbs are no longer leaking! I ran the bike for 10 minutes at idle and no issue! Yay!

It was having a hard time holding a steady idle though, even once warm. I would set the idle at 1,800 and then rev it. It would want to stick at 3,000, it would slowly come down with a little coaxing by lowering the idle speed screw and then it would drop a little too low and I would have to raise it back to 1,800.

I decided to take a temperature reading at each exhaust header. 1&3 were at ~215 deg, #4-175 deg, but #2 was only at 115 deg. The exhaust felt cool to my hand even. Does this mean #2 is not firing? Or something else? What would be my next steps to troubleshoot?

[calj737]

#2 is not getting fuel. Check the plug. How’s it look?

[joegeis]

Plug was dry and didn't smell particularly strongly of gas? Below is a picture. Maybe I'm just throwing money at the problem, but I did just buy new coils, plugs, caps and sparkplugs. I went with the Sakura coils from PartsNmore #17-6823 based on a recommendation from Hondaman. I bought caps from the same site (NGK FD05FP and XD05FP). I still have Hondaman's ignition to install as well, which I'll do when I receive these new coils.

I ran it pretty good through the neighborhood today, getting the engine up to 6k RPMs. It continued to struggle with holding a steady idle. I had it warm at 1,800 before leaving and a few minutes later at a stop sign, it was idling at 3,000 again. All cylinders were at 220 degrees except #2, which was at 135 after the 10 minute ride.

I checked for spark and was getting spark, but it was orange, not blue. Given I have done literally everything feasible to the carbs within the last week, I'm not sure what else I can do.

[calj737]

Open the peacock, then open the bowl drain screw for #2. Does gas come out? I’d venture a guess the valve is hung up or parts in laying in the bowl during reinstall. That is not uncommon.

If no gas comes out, drop that bowl and have a peek. This is purely a fuel issue, no money needs to be spent.

[BenelliSEI]

That plug looks dry and I agree with above. Check see there is fuel getting into the float bowl. Did you “bench sync” the carbs? Put vacuum gauges on them yet?

[joegeis]

Yes, gas drains when I open the drain screw with the petcock on. I did "bench sync" when putting the carbs back together again, but it did not needed adjustment. I vacuum synced them right before taking them off the last time, but have not done it since the recent cleaning/polishing, when I also replaced the floats and float needles.

Going back and looking at my posts from when I was trying to sync the carbs last time, and I did an exhaust temperature check, #2 was fine, it was actually #3 that was low temp, which is fine now!

[RAFster122s]

You would not be the first, nor the last, to pull a float bowl to find a jet either loose or in the float bowl. Start with your cylinder exhibiting the issue...likely no need to mess with any others.

[BenelliSEI]

You would not be the first, nor the last, to pull a float bowl to find a jet either loose or in the float bowl. Start with your cylinder exhibiting the issue...likely no need to mess with any others.

Or an upside down float….. don’t ask me how I know.

[joegeis]

okay, I'll get my short screwdriver and try to get the bowl off without removing the carbs again 

I'll report back this afternoon!

[grcamna2]

okay, I'll get my short screwdriver and try to get the bowl off without removing the carbs again 

I'll report back this afternoon!

I like small allen-head screws(better than phillips-head)for float bowl screws;it helps to remove them when the carb. rack is installed.  Make sure not to over-torque them,which will strip the small threads. 

[joegeis]

oh yeah, that would be way easier!

[joegeis]

I took the carbs off and inspected #2. Everything was as it should be. I already verified that the bowl had gas. I don't think it's a carb issue.

So I put the vacuum gauges on, thinking maybe it just needed to be synced again. Had a hell of a time getting a steady idle. It wanted to rev up to 3k and stay there. I would use the idle screw to try and bring it down, and it would drop fast to 1k and try to die. I would turn the screw slightly and it would go back up to 3k. Like it was bouncing. I would also hear a pop at the exhaust and would see #2 vacuum gauge need tick when it would. I also noticed arcing between the spark plug boot and the engine on #3.

I inspected the #2 plug after and it looks normal to my untrained eye.



Video: https://photos.app.goo.gl/A1NoGhUfQi8tzAyQA

[grcamna2]

The spark plug is fouled.

[newday777]

" I also noticed arcing between the spark plug boot and the engine on #3."

Fix that situation. Either you have a bad plug cap or a bad wire leaking spark that need replacing.

[calj737]

To assess a spark plug’s condition, you need to look at the ceramic insulator and the electrode. The strap is mostly immaterial. So turn the plug endwise and have a glance. There seems to be some brown color on it and the electrode appears wet. These conditions indicate “fouling”. It’s not terribly fouled but associated with poor spark for air/fuel mixture you’re running.

Compare #2 to #3 or even swap your coil leads and see if the problem follows the change.