XJ550 Maxim Carburetor

I got my XJ550 Maxim running but the carburetor still leaks gas from #3 and #4. I replaced the bowl gaskets but it still leaks. Any suggestions? Also if anyone has a diagram of the carburetor like an exploded view?

 

Leaks how? Down the side of the bowls? Into the crank case?
Either floats set too high, needles not sealing, petcock not working, or some combination thereof.

 

Leaks down the side of the bowls.

 

Ok, how much work have you done to your carbs? Are they still on your bike?

 

I took them off because it was leaking everywhere. All I did was change the bowl gaskets

 

Needs more than that. Your fuel rail o-rings are probably shot. In the long run it's better to break the rack and do a thorough refurbishing.
IN THE CHURCH OF CLEAN

 

Definitely read the link above. It sounds like you are getting everything sorted for a project bike. The carbs should definitely be attended to with special attention. If the fuel rails are the culprit you'll need to split the rack regardless, so you might as well take care of the whole shebang. There are a ton of members here who have gone through the process and can help you along.

 

this link has a link to cut away carbs

Something New, Something Naked

 

This link has a cut away to Conway Twitty:

 

I have all the parts on the way to rebuild my carb. My main issue was 3 and 4 leaking fuel but I figured I might as well rebuild all if I'm going through the trouble. Anyone know where I can find the main supply line that splits into a T? Also #4 had a loose needle, how do I fix this? And what parts are safe to polish inside the carb?

 

are you talking about the float needle valve ? or mixture screw?

Mikuni Carb Fuel Tee, /Alum XJ550, FZ600, YX600 Radian 4U8-14988-00-00

• $19.95

 

The link I provided above has all the info you need about rebuilding you carbs.
Start a conversation with Chacal for the correct parts.

I'd also like to know which needle is loose. There are three: The main fuel needle, the float needle, and the idle mixture needle (commonly referred to as the pilot screw).

 

It's the float needle. Since it's loose I'm assuming that one of the problems is that it doesn't seal.

 

it has an oring around it to seal it ,held down by a little retainer bracket

 

I saw the retainer bracket but didn't want mess with anything yet. I'll take it apart and check it out

 

Is the needle loose or the seat for the needle? The float needle is a loose fit in the seat bore, and seals when the cone of the needle is pressed against the conical seat by the float tang.
If the seat is loose in its bore then you'll need new o-rings. This is a sign that all the rubber parts should be replaced (except for the slide diaphragms, unless they have holes, or are cracking).

 

The actual needle. Took the float out and there is play in it.

 

There is supposed to be some play. It's a loose fit in the bore so that the needle can't bind. If it's really sloppy then you should replace the needles and the seats.
You might see if the problem is the needle or the seat by swapping the needle from another carb to compare the fit.

 

Are the screws/bolts on the carb specific or could I replace them with ones from the hardware store? Many of them are rusted and are probably gonna get stripped

 

1. Get a JIS screwdriver (recommended) or a hand impact driver (should get both really), or the screws will all get stripped no matter what. None of the crosshead screws on the bike are Phillips.

2. They are standard thread sizes, but you will need to shorten a few in order to allow them to fit. The easier way is to order screws from Chacal if it's in your budget. Either way you can switch over to caphead screws if you like.

 

Eliminate future headaches...take the entire rack to Church.

Gary H.

 

http://www.xjbikes.com/forums/threads/mikuni-carbs-part-1-exploded-view-with-pics.31061/

 

It doesn't matter if the needles are sealing or not, if the gasket is leaking. If gas is leaking out, the level will drop,the needle will open, and more gas runs in......either way, the process continues.

If the fuel supply tube o-rings are leaking, the fuel valve will be of no consequence, there, either. The fuel supply tubes and o-rings are in line BEFORE the fuel valve.

So you do need to break the rack down and do the whole thing correctly.

 

And then was...D@mn, y'all smell something burning? FIRE!'

Gary H.