XJ 550 Maxim Cracked Carb Enrichment Tube

Hey everyone, first of all thanks. I picked up a trashed XJ550 with no title as my first bike with the intent of learning some mechanic skills. This forum has helped a ton rebuilding and fixing it up.

I’ve gotten myself into a pickle and am trying to avoid buying a new carb body.

I’ve rebuilt the carbs, but being a novice I made a mistake early on. I tried to pull the enrichment tube expecting it to be in the rebuild kit without checking first when I first started restoring the carbs.

After unpacking, stripping, cleaning following the Church of Clean, replacing hardware, dry setting the floats and reracking I started doing a wet set. Not fantastic results, but I’m currently at 2.7mm on 3/4 carbs…but one keeps flooding.

I drained them all, closed the drain plugs, filled them up and watched for where the leak came from. It doesn’t come from the tube which distributes fuel between the carb bowls, it actually seems to come from the output of the carb and both of the small holes on either side of the mouth.

First I disassembled that carb, reinstalled all the hardware and tried again. It still flooded. Puzzled I remembered pulling that tube, and checked…sure enough the plier marks are in the enrichment tube of the carb that’s flooding and I noticed some hairline cracks in it.

My first question is…is this my issue? Sure seems like it.

My second question is whether I should bite the bullet and get a new carb body, or if I should attempt to pull it again, solder the cracks, and attempt to reseat it.

Thanks!

 

the enrichment tube should not cause the carb to overflow, unless its so bent it fouls the float (unlikely)
your problem is the float valve, did you replace them in the rebuild kit?
fuel can also leak past the float valve via the "O" ring that goes around the outer of the brass valve, did you replace these and are you sure you did not damage the new ones when pushing them in? i always put some silicon grease on new seals

 

I did replace the float valve. I’ll pull it apart again and check that the O ring is good. I may have not noticed it missing or something like that because I only reassembled the one carb.

I have some spares, so I may replace the entire float valve assembly and give it another go.

It’s certainly not that bent. I’m not even sure the bowl would seat if it was?

Should I solder that bad boy while I’m in there?

 

wel yeh , maybe but bear in mind that there is a hole through the tube near the top , you can post pictures after you've done 5 posts, so you could just post some gobeldy- gook for a few posts

 

Can’t post pictures or Google drive. Spamming.

Pictured are all the parts inside the bowl, including removing the float assembly and o-ring inspection. Everything looks fine.

Also pictured are the areas where I see leaks.

I messed the stem of the enrichment tube about 10 times worse than pictures here trying to remove it so I could get enough heat to solder it, but it appears that I’ve only damaged the brass jacket not the tube itself, nor do I think fundamentally this should actually be too big of an issue from looking here…

 

More spam

 

Even more spam so I can post a picture

 

why I think it’s the enrichment tube I messed up…

https://www.xj4ever.com/inside your carbs.pdf

 

The starter/choke/"enrichment" tube (the thing with a wire stuck into it in the first picture) is not designed to be removed from the carb body. As far as I know, there are no replacements available for it. The small fracture in it may or may not affect its performance, but it would only be an issue when the "choke" is on, and even if it does affect performance in a negative way, the three other carbs also have a choke system which should be enough to get an engine started during moderately cold conditions (maybe down to freezing temps) --- assuming that the engine/carbs are in good tune otherwise.

In either case, that fracture in the choke system suction tube would not be a cause of flooding.


In the 2nd picture....the one with the red circles.......what is the little piece of wire (?) sticking out of the air jet? Smaller red circle, 4-o'clock position?

And in that same picture, what is the purpose of the larger red circle around the vacuum piston and main jet needle............what are you trying to "show" us via that red circle? Are those the spots where fuel is flowing out of? If so, the carb is flooding significantly, and it's either the float needle is seized (open) within the brass seat, a bad o-ring on the seat, or the float is adjusted incorrectly or seizing on its pin.



In the 3rd picture, that o-ring looks to be in good shape.


In the 4th and 5th pictures, make sure that an old o-ring is still not down in that bore hole where the float valve brass seat rests. It would be odd to have one down in there, as the o-ring is captured within the brass seat, but the last image almost looks like there's "something" at the bottom of the bore?

 

I found it. It’s a combo of things that happened to land on this carb. (What are the chances?) the new float is shaped in such a way that it does not operate properly, and in the process of messing with it I seized the new valve.

I got the seller to send me a replacement float and valve.

for anyone who happens upon this…

1) Don’t remove the enrichment tube
2) Don’t restore and paint your carb covers before you wet set. No matter how careful you are you’re gonna get gas on them and have to repaint.
3) Watch for the center needle to fully seat. If you have to push the tab of the float down so far that it makes contact with the edge of the float needle body rather than the “piston”/needle coming out of the center of the float valve assembly, something is wrong with your float/valve.
4) Prebend the tongue of the float down to start out with, and then pry it up to adjust dry set…or alternatively remove the entire float and bend the tab. Don’t try and press down the tab with a screwdriver or you may break the valve needle.