Carb ID

[New2Me]

I searched for Carb ID but I didn't come up with anything useful. Is there something on here that explains how to identify the different carbs that come on these bikes? I dont want to open them up until I have the parts ready to put in them.

[BA80]

The 78 - 79 carbs have the mixture screws sticking up, 4 "fuel Ts" 2 for fuel and 2 for bowl vents, and the bowl drain screw is in the bottom of the bowl.

80-83 the mixture screws ar sunken into the body, 2 fuel Ts, and the bowl drain screw is in the side of the bowl.

There are quite a few other differences but these are the easiest to spot.

[DGXSER]

There are two basic types, early 78-79 and later 80 and up. The XJ had a different type of choke than the XS, cable operated versus lever on left side.

The simplest way to see if they are the early or late is the number of Ts between the two left and right sets. If there are four total, two top and two bottom then it is surely the early model. If there are only two, then they are the later style. Only the 81 version had the side drain for the bowl, 80 still had the bottom plug. Also, the early model carbs the idle adjustment screw points toward the top of the carbs and is on the back side by the air box. The later model cabs the idle adjustment screw points down and is on the engine side. You can also look at the inlet bell of the carbs. The early models have three openings in the inlet bell, the later models have four (fourth one is the bowl vent, thus no need for upper Ts).

Now, it will still be important to look inside if they look like 80 model carbs. Some of the earlier issued 80 year carbs still had the covered pilot jet like the 78-79 model carbs with the crossover from the emulsion tube to the pilot jet tunnel, but all else is the same as the other 80 model carbs.

Honestly, you need to open them up, get the parts out first, then you will know what needs replacing. Otherwise you will be buying parts you may not need, or missing parts you may find you need.

[Lbrown311]

I agree with DG. You need to open them up and see whats goin on inside them. Take them apart, soak the bodies, bowls, and covers in Hot water and Pine-sol over night. While you are soaking them you can order your parts. Then you can cut a day out of your waiting time at least while they are soaking. Give them a good rinse in Hot water afterwards. Use a wire brush on anything REALLY gummed up. Spray all your jets with carb cleaner, and just give the diaphrams a good wipe down (don't use something harsh on them as they are spendy to replace)

You could have a number of problems you don't know about untill you open them up. Best to know what you are getting into before ordering parts. Find out by looking. Good luck

[natemoen]

The 78 - 79 carbs have the mixture screws sticking up, 4 "fuel Ts" 2 for fuel and 2 for bowl vents, and the bowl drain screw is in the bottom of the bowl.

80-83 the mixture screws ar sunken into the body, 2 fuel Ts, and the bowl drain screw is in the side of the bowl.

There are quite a few other differences but these are the easiest to spot.

Greg, did the '80's have the same style float bowl as the earlier and then in '81 they switched to the side drain bowls?

[DGXSER]

Greg, did the '80's have the same style float bowl as the earlier and then in '81 they switched to the side drain bowls?

My name ain't Greg...but...

QUOTE=DGXSER;331294]Only the 81 version had the side drain for the bowl, 80 still had the bottom plug.[/QUOTE]

Granted, I believe the XJ also got the side drain screw as well, I was speaking of the XS models.

[natemoen]

My name ain't Greg...but...

QUOTE=DGXSER;331294]Only the 81 version had the side drain for the bowl, 80 still had the bottom plug.

Granted, I believe the XJ also got the side drain screw as well, I was speaking of the XS models.[/QUOTE]

Yeah but I quoted greg, and your post wasnt up there when I first clicked on the thread and then walked away for some coffee and then came back and read the thread.

[BA80]

Sorry for the abreviated post earier but I'm at work and sometimes I have to act like I'm actually working.

Thanks Don. However, my SG had the side drains on the bowls before I put the earlier carbs on.

They may have been changed before though. Who knows.

[crazy steve]

...my SG had the side drains on the bowls before I put the earlier carbs on.

My SG also has the side-drain bowls on the carbs, so that may have been a later-in-the-year running change...

[natemoen]

I tried putting the float bowls from '81 carbs on the carbs for my '78 and found that they do not fit. The brass tube that goes down into the float bowl is slightly moved and the hole in the bowl is also moved. So yeah it must have been a switch mid year cause they don't interchange.

[crazy steve]

It's not that the brass tube is different, it's the carb bodies and bowls that are different. The side-drain bowls are slightly smaller inside, and hit on the float posts of the early carbs. I discovered that when I attempted to repair a broken post with one of my 'kits' and the bowl wouldn't go on. You can fit the early bowl to the late carb, but not vice-versa.

You'll also have trouble with the larger brass floats in these bowls; you have to use the plastic floats for enough clearance...

[natemoen]

It's not that the brass tube is different, it's the carb bodies and bowls that are different. The side-drain bowls are slightly smaller inside, and hit on the float posts of the early carbs. I discovered that when I attempted to repair a broken post with one of my 'kits' and the bowl wouldn't go on. You can fit the early bowl to the late carb, but not vice-versa.

You'll also have trouble with the larger brass floats in these bowls; you have to use the plastic floats for enough clearance...

I don't have the '78 carbs off and open to compare but I though the brass tube was moved a little more towards center and the hole in the bowl was round rather than oval on the earlier carbs.

[XSTrey11]

[QUOTE=crazy steve;331334] You can fit the early bowl to the late carb, but not vice-versa.

I think this is what happened on the carbs for my 80G because mine have the drain on the bottom ad apparently it should be on the side?

[crazy steve]

I don't have the '78 carbs off and open to compare but I though the brass tube was moved a little more towards center and the hole in the bowl was round rather than oval on the earlier carbs.

I double-checked that, and you're right; they did move the tube slightly, about .1", so the early/late bowls won't interchange. But the late type bottom drain and side drain bowls have different internal dimensions, as the bottom-drain bowl would fit over my 'kit', but the side-drain wouldn't...

Trey, there apparently was a mix of bowl types on the '80s carbs. Most seem to have the bottom drain bowls, but some (off higher serial number bikes) appear to have came with the side drain bowls, assuming a PO didn't swap carbs. Makes absolutely no difference in carb performance...

[DGXSER]

The only real difference between the 80 and 81 carbs is the jetting and the bowl drain. Every set of 80 carbs I have seen and worked on, three or four and one that was bought off the showroom by the current owner have the bottom drain. The side drain is a nice feature, so I have no doubt some got swapped around. Or could be an entire carb swap which is not uncommon.