Leaking carb 82 seca 550

This is my first post here. Just got my first street bike and Im having some troubles and I was hoping I could get some advice from here. Its an 82 seca 550. It's Mostly in great condition except the carb is leaking gas.

I have never had a carb apart before but I am a bit mechanically inclined, so I thought Id give it a try. I did some reading and then went and tried it out.

I took the float bowls off and all the floats seemed to be moving fine. But the t that splits the fuel line going into the carbs was cracked and it was pushed over to one side and I thought it might be leaking from there so I centered it and put everything back together. Still leaking. I was told by a mechanic that it was probably one of the float needles (I think. Like I said Im new to this) So I ripped everything out again. One of the needles was a little sticky so I cleaned it with some carb cleaner and it was moving freely. Put everything back. Still leaking. It looks like its dripping from the gasket but its hard to tell when its on the bike. All the gaskets were stuck on the float bowls except the one thats leaking so I was thinking maybe that could be it. Should there be some kind of gasket sealer on those?

Another thing the mechanic said it could be is the float height. But he said thats less common. How do I go about checking that?

Other than this the bike runs great so this is pretty frustrating as I would really like to ride this bike! Sorry about the long first post but hopefully someone can lend some advice.

Thanks in advance!

 

First off, you probably have one or more obstructed float needles/valves which is not shutting off correctly.

You're going to have to get into a much more thorough carb cleaning than what you've done so far to fix your problem. There is no "easy answer" for this.

Then, while the carbs are off being cleaned, you can check the float levels correctly, as well as do a "bench sync" to prep for final on-bike tuning.

YOU NEED A SERVICE MANUAL. There is a lot more you're going to need to do to an old bike to make it safe and reliable, and you'll need a book for that.

BEFORE any more riding: check the rear brake shoes for delamination. This is serious; a common problem; and can wreck you, no joke.

You've come to the right place; we can help. But there ARE NO SHORTCUTS for most of the issues; carbs is one of them. You're going to have to dive in and do it right, or it won't ever work right.

 

Thanks for the quick reply. I would really like a service manual. I was looking at them the other day and founf several. They all ranged in price from $20-$70, so I wasn't really sure which to get. Can you suggest a certain manual? Or is there somewhere with online manuals? I know from passed car manuals that some can be almost useless and others are much more helpful and in depth. I have only had the bike for 2 days so I havent had much time to do everything I need to yet but I am planning on doing things right. And I definitely wont be taking it out without checking everything over for saftey issues. It's just that its kind of taunting me just sitting there. I know it still needs a bunch of work but it would be nice if I could get it running without pouring gas everywhere.

Thanks again

 

The best service manual is a factory manual; or even better a combination of the factory book and the Clymer (the only aftermarket book for the 550.)

Don't get me wrong, the Clymer is good but it does contain some omissions and errors; I "soldiered along" with just the Clymer until I scored my factory book off eBay ($15.)

I was serious about the rear brake; drop the back wheel and have a look before you do any more riding. Read this entire thread: http://xjbikes.com/Forums/viewtopic/t=15874.html

If you read my sig and check my gallery you'll see that I'm a 550 Seca fan, big time. Unfortunately, the problem with your bike is going to need to be fixed RIGHT for it to be fixed. Carbs are the Achilles' Heel of these bikes, and one of the reasons my 650 isn't running yet. It pees gas all over itself too.

Get some basic bike info into your sig; and reply to this posting with some history on this particular machine; it will help us give you more "focused" advice.

Welcome aboard; get that Seca fixed right and you will love it.

 

Alright I found a copy of a Yamaha service manual online.

And as for details about it.
It came from texas and has been kept in a garage for most of its life so its in pretty good condition. It has just over 19k miles on it. The plate on it has a '98 insurance tag on it so Im guessing it hasnt been ridden much or at all lately. It does start and run pretty good, but like you said it pees gas all over itself. Its got a bit of an electrical problem too but I don't think its really a huge deal hopefully I can sort that out. I cant think of any other details right now but I've been reading this manual and I'm going to go rip the carbs out again. What is the best way to do this? I was taking out the soft rubber hoses that go into the air box and then taking the carbs out. Its pretty cramped in there an I kinda had to reef on the rubber parts to get them out. I dont want to damage anything so I thought Id ask.

I don't have my compressor here to clean it out with but would it be worth it to use one of those cans of computer duster?


And how do I check the float height. The manual says to hook up a level gauge adapter (special tool) . Obviously I dont have one of those and it sounds hard to get. Not sure how else to measure it though.

And thank you again. Like I said before I pretty much have no experience with carbs (or these bikes for that matter) and I really appreciate the help.

 

ok so I took it apart again. It's pretty clean in there considering how long its been out of service for. The guy I got it from replaced some parts in there so I guess thats probably why.

Well the float in the carb that is leaking was a little bit lower (higher I guess if the carb is right side up) So I adjusted the tab on the float so it was the same as the others. I took out all of the float valves and they're all spotless. All the needles look like they're in good shape and not damaged or dirty at all. One of the floats looks brand new and it was higher than the others.

Well anyways that didn't work I put it back together and fired it up and I thought it had stopped leaking and then it started again.

The cracked fuel supply T doesn't look very good either and It seems like that is going to be a real pain. From what I can tell it looks like I have to separate the carbs to get that out am I correct? I don't know how likely this is but could it be that the floats are working but when the float bowls fill up and the valves close gas is just leaking out of the T? It's hard to see in there but I'lltry to have another look tomorrow when its light out.


It wouldnt be so bad doing all this trial and error if it wasn't such a pain getting the carbs in and out of the bike.

And even though Im having such a hard time trying to fix this thing, Im learning a lot, and I already love it!

 

The "special tool" is nothing more than a length of clear plastic tubing. You can invest in one with graduations printed on it, but it's not 100% necessary.

You "hook it up" by attaching it to the carb drain outlet; you can build/accomplish the whole thing for about $3, you simply need 2' of clear tubing and a "fitting" of some sort to jam in the outlet hole. I used a plastic "junction" from my Mity-Vac kit, but various fittings of the like can be got at any auto parts store.

With the carb rack mounted OFF the bike, somewhere flat and level, you hook up a fuel source and "fill" the rack. Then use the clear tube to ascertain the height of the fuel in each carb, one at a time. This is illustrated in the manual.

This procedure will also reveal the source of your leak, since you'll be able to see it. If it IS the "T" then yes, the rack will need to be partially split.

Check chacal's catalog (XJ4Ever, Supporting vendor in the forums index or the link at upper right) for details on the "T."

Chacal also offers the printed tube if you want to go all out.

oh, and it sounds like you are doing the carb rack dismount correctly-- did you find the part in the manual about which screws to remove/loosen to move the airbox back about 3/4"?

 

Alright the only problem with that is that I can only check the outside carbs. The inside ones have stripped drain screws. I will check them though.

Can I measure the float levels dry? I found some info on doing that but not exactly sure what the measurements are.

And I didn't find the part about loosening the bolts for the air box but there were some bolts missing under the seat and the air box moves back and forth. Maybe the previous owner forgot to put them back.

 

Unfortunately, "dry" float levels are only a starting point.

JUDICIOUS use of heat (with the bowls OFF) should help break the screws loose.

You're going to need some of this: http://www.kanolabs.com/google/ It works when others don't and will save your bacon.

Worse case scenario: Check the ouside two, switch the bowls (#1-#2 and #3-#4) check the inside two.

There are two bolts just in front of the fuel tank mounting point, (in slots) and one either on or under the tool tray (under, IIRC) that has to come out. THAT bolt has been missing on every Seca 550 I've seen.

 

Alright I measured the fuel level on the 2 outer carbs and the fuel came up to the bottom of the carb body on both sides. And the manual says it should come to around the washers on the float bowl. So how much should I adjust the tang on the float? The manual just says that if the level is wrong to adjust the tang slightly.

Oh and if I do heat the drain screws up and get them out where would I get new screws? Order them or is it a common part?

 

So I went and got some tubing and hooked the carbs up to the tank while they were out of the bike. Looks like fuel is leaking out of the connection between the 1 & 2 carbs and 3 & 4. Is that just a metal sleeve with some o rings on it? If I take the carbs off the rail am I going to need the yics tool to sync them after? I wish I had have just done this in the first place. Would have saved a lot of tinkering. At least now Im really good at removing and installing carbs in a 82 seca 550. Could probably do it blind folded.

 

In the order that you asked:

You adjust the tang a VERY SMALL AMOUNT. So small that if you're sure you bent it, it's probably too much. Think "nudge."

chacal carries all of the correct carb parts http://xjbikes.com/Forums/viewtopic/t=14561.html they're not something you will find at the hardware store.

Yes, it's a metal tube with o-rings; see link above to source the correct parts.

The YICS tool is to block the ports in the engine when doing a running vacuum sync. That would be part of this whole process whether or not you "break the rack." You will eventually need a YICS tool and some iteration of manometer, homemade or store-bought, for final tuning.

"I wish I had have just done this in the first place. Would have saved a lot of tinkering." This was what I was alluding to in my initial response. There are no shortcuts; you either do it right or keep doing it.

You will need a "surface plate" to re-rack the carbs; since few of us own such a thing, a short construction level can be used as a reasonable substitute, along with a steel ruler.

Be sure to bench sync the carbs (and get those float levels right on) before putting them back on the bike.

 

I got the fuel levels good in # 1 & 2, and in my defense I didnt know I could check them off the bike until yesterday so I wasn't really trying to take a huge shortcut, just thought I'd try one more time before I drove down to the parts store :lol:

So I'll order some parts and tools and take it from there. In the meantime I'll work on that fuse box.