To Seafoam or not to Seafoam

[LAB3]

When I swapped out the lines on my current bike two years ago I used just plain jane rubber hose from the auto parts store. Then about six months back I came across a hardware store that had bulk fuel line made of that same solid plastic looking stuff that the stock lines are made of and grabbed three feet of it and threw it into the trailer thinking I'd replace the rubber lines with it when I had a reason to pull the tank off to do something else.

A couple of weeks back I finally got around to doing just that as it was (well beyond) time to check my valve clearances. Sure enough, the inside of that rubber hose was awfully "gooey" looking. The fuel system wasn't giving my any problems up to that point but I'm darn glad I swapped out those lines before it did. Rubber hose works well enough, until it doesn't!

[rphillips]

I've heard about it will deteriorate "O" rings, but not heard of gumming anything. Dissolving gum, or deposits, is what it's designed to do, it'd be hard to imagine it may do the opposite... Hoping things get fixed without taking carbs apart. If you do got to take your carbs apart to check the needle & seat, our Suzuki's have "O" rings on the seats that cause same problem as leaking needle, I took mine apart 3 times before I found that "O" ring the problem & needle & seat was fine... Good luck.

[nvr2old]

Thanks for all the insight, guys. The fuel lines on the bike are actual fuel lines and look to be fine, thanks for making me look. I turned the petcock on this morning, and sure enough it's still spurting a stream of gas out of the overflow tube just about every 30 seconds or so. Almost like it's under pressure. I'll try filling the bowls with straight Seafoam and leave it overnight again. If that doesn't help, I guess I have no choice but to pull the carbs..argh. The bike runs amazingly well, so that's one good thing anyways..

[unfocused]

I'm a firm believer in both Seafoam and Lucas. However, niether of these will fix a damage rubber part or stuck float - a dirty jet will not make fuel squirt anywhere.

[wyly]

I have a CBX and those 6 carbs are complex and very sensitive. I normally run a tank of fuel with seafoam through it every fall before I put it away for the winter. Two years ago I forgot to add seafoam I didn't it really didn't perform well sputtering and hesitating on spring startup, I added some seafoam to the tank and did an Itialian tuneup, it cleared up any problems in less than 50 miles

Last fall I did the seafoam procedure and drained the carbs to be sure, last month it fired right up first try with no issues.

[nvr2old]

Well..no go on the 550F. After letting the Seafoam soak in the carbs overnight, the carb still spurts gas out of the overflow tubes. I guess it's time to pull the carbs and have a look-see inside. I'll order new rubber intakes and rebuild kits to have on hand. Thanks for all the help.

[steve murdoch]

Well..no go on the 550F. After letting the Seafoam soak in the carbs overnight, the carb still spurts gas out of the overflow tubes. I guess it's time to pull the carbs and have a look-see inside. I'll order new rubber intakes and rebuild kits to have on hand. Thanks for all the help.

Twenty? years ago i revived a few CB400-4 bikes and found http://forums.sohc4.net/ an excellent site for tech help.

[trevor]

Another vote for seafoam I had two gummed up float bowls on my 1100 this year and threw some seam foam in and bike ran great!

[rphillips]

I've not tried the letting Seafoam sit and work, all of my positive results came from riding the bike, kind'f letting the seafoam flush things out. Not say'in just letting it sit in there won't work, just know what has worked for me.

[salty_monk]

Yeah, same for me. If you can't get it running (and preferably ride it) then I don't think seafoam is the answer.

[nvr2old]

The bike actually runs great. I put about 20 miles on it after putting the Seafoam into the gas tank. The carb overflow continued to spit gas at a 30 second interval. That's when I thought I'd try Chuck's method of straight Seafoam in the carbs overnight, drain, fill with gas, go for a ride and see what happens. Still leaking out the overflow tube. I ordered a rebuild kit and new rubber intake manifolds for all four carbs, those should be here early next week. A Honda Tech friend that I have will help me pull the carb rack and we'll go in and see if we can figure out why it does what it does. Again, a shame because the bike really runs well.

[chuck hahn]

Are you positive the tube isnt cracked? I put a piece of tubing on them and fill the bowl with water. then plug the hole off and blow in the tube. If its cracked youll see bubbles.
Secong thing is just maybe that carb needs a little higher float ht to shut off the fuel. Check the float needle to see that the little spring loaded tip is free and responsive. Service manual shows how to do a wet fuel check and that will give an indication if the fuels rising too high and spilling.
If you find a cracked tube clean it with some fine sand paper and solder the crack..done

http://manuals.sohc4.net/cb550/

[Nessism]

Are you positive the tube isnt cracked?

Make that, the overflow tube in the float bowl. It's very common for them to crack in Keihin carbs. Not overly difficult to replace, but a bit of a project.

[Spyder]

I use Stabil every fall, and Seafoam every spring in everything I have with a 4 stroke engine. NEVER had a problem yet. That includes carbs, and FI.

*Side note: I typically use double the "recommended" dosage for both of them. EVERY YEAR, EVERY ENGINE.

[nvr2old]

Just a quick update on my carb problem. The good news is my Honda Tech friend was finally able to come for a visit from 100 miles away. We spent Saturday pulling the carb rack off the 550F and disassembling all 4 carbs. They were amazingly clean and easy to take apart. Installed a new needle and seat in the far outside problem carb and there was indeed a tiny chunk of crap that was keeping the float from closing the needle causing the overflow. He adjusted the float level while in there and bent the tab on the float just a pinch to push the needle closed a tad bit sooner. While the carbs were off I installed new factory rubber intakes coming off the head. Re-installed all 4 carbs and it works beautifully again. My friend, Lee, is an amazing mechanic. So nice watching someone who knows what they're doing, smoothly and correctly.