xj carbs

[ajvot]

I have been working all winter to get my XJ on the road and have run into quite a problem with the carbs. I bought this bike totally pulled apart and was missing many of the specialty parts, such as the octopus. I have downloaded the diagram for fuel line routing (thanks Wayne), for getting rid of the diaphram system. I don't think the carbs I have are original to the bike and was hoping someone could help me out with the rest of this. There are three t's in the carbs; two between 1 & 2, and one between 3 & 4. One of the t's between 1 & 2 is below the others. Which one's are for fuel lines. Also, there is a small nipple on the right side of each carb. What are these for, and where to they hook up? I have gotten great help and inspiration from reading all of your posts and hope someone can come though for me. A rough sketch or diagram would be great if possible. I'm so close to getting this thing on the road again. Thanks a million.

[tab1324]

can you post a photo?

If you can post a photo, I bet we'l be able to sort this out. I've got an XJ and went through the carbs a few times... I don't recall any "nipple" on the side of the carbs... The fuel lines should go on the two tees between 1/2 and then 3/4. left petcock to 1/2 and right to 3/4. I'd ditch the octopus - I did and I think most are doing the same.

Sounds like maybe someone has swapped carbs around and you have (3) set up with fuel inlets. You should be able to remove the tee but I dont' remember exactly how they hook up and I can't really see it on mine with everything jammed in.

Tom B.

[TopCatGr58]

Hey there AJVOT,

Sounds like someone did some serious mixing of your carbs!

The XJ should only have 1 inlet for the FUEL "T"s, at the level just above the fuel bowls. If there is another port inlet and "T" there above that, then those carbs are from the 78-79 series XS's, and those are Bowl Vent ports, NOT Fuel inlets!

From what you described, you probably have a pair of 78-79 carbs on your left bank, #1 and 2, and perhaps the OEM 82 XJ are on the right bank, with only 1 "T" inlet!?
T.C.

[Ken Talbot]

The two left carbs, with two "Ts" between them, are carbs from a '78 or '79 bike. The upper T is an atmospheric vent for the float bowls. The lower T is the fuel supply to the bottom of the float bowls.

The single "T" between #3 and #4 indicates those carbs are from '80 or '81, or even from an XJ.

The nipples you're talking about on the side of each carb could be the chokes for each carb, but these would be on the left, not the right. The choke on everything from '78 to '81 is operated by a thum lever attached to the left side of carb #1. The choke on your XJ shold be operated by a thumb lever and a cable on the left handlebar.

Does any of this sound close to the mark?

[Ken Talbot]

Dang, TC, you must read and type way faster than me....

[Czekus21]

hey there ajvot. check out your PM.

[ajvot]

xj carbs

Sounds like my "Frankenstein" carb setup may be for sale or trade in the very near future as a "parts only" item. I'm working on getting some pics posted, even though at this point they may be used just for laughs.....or possibly a great trivia puzzle. Thanks for the info so far.

[TopCatGr58]

Originally posted by Ken Talbot
Dang, TC, you must read and type way faster than me....

Hey Ken,

Well, I don't profess to be able to read too quickly, my mouth can't move that fast! But I did take a touch typing class in High School cause my handwriting was barely legible, thought I'd never be able to turn in a paper in college, and this was way before the use of personal computers! Was about the best course I ever took, aside from Auto shop!!

Hey AJVOT,
You might not need to get a complete bank, probably just 2 of the newer styled, or older styled carbs depending on how much adjustability you want in tuning your carbs!? The older style provides for more fine tuning!

T.C.

[ajvot]

xj carbs

The smaller nipples I was talking about are on the right side of each carb, just above the bowls. It is the right side if you are looking at the carbs from the airbox side (back). Ken, you are correct in stating that the choke is a cable from the left handlebar.
There is also a knob, which is at about a 40degree down angle between 2 and 3,that screws in and out. It appears to be some kind of choke ajustment because it touches a small plate on the choke lever that connects to all of the carbs. According to the information I have, the xj should have a pull out/in lever for cold starting. I think I need to find a full bank of carbs rather than trying to put two of these together with two others. I like to be able to follow the manual whenever possible since this is the first bike I've assembled. Seems like every time I try to put new parts into an assembly, I'm still missing something.
Keep the comments coming. Any information you guys can give to us newcomers is great.

[TopCatGr58]

Hey there AJVOT,

Well, there aren't supposed to be any nipples on the right side of the carbs, but there are supposed to be ports in line with the fuel inlet ports on the other side of the carb, and depending on whether it's the right one of the linked pair, that port is supposed to be plugged, same for the left port on the left carb of the pair.

That screw in the middle is the Main Idle adjustment screw, turning it moves all 4 carbs together in opening or shutting the butterfly valves/throttle plates, you use it to set the idle once you get the carbs synchronized!

Czekus21 is parting out his XJ, he might have a serviceable set of XJ carbs, try contacting him!!

Trying to post this message again, the FORUM database is acting up!!! T.C.