Carb differences help please???

[Guest]

So I bought a 1981 gs550. It was missing the carbs and I find a rack on eBay and they said it came off a 1980. So I bought them and I go to put them on and the boots on the bike are to big for the carb. Is there any differences between the 1980 and 1981??? Or when do the carbs change looks? Because I have a feeling it's a late 70s carb.

[Nessism]

The '80-'82 550 carbs are all pretty much the same.

You can get a factory service manual for your bike here...http://members.dslextreme.com/users/bikecliff/

[Dylanblake]

So what do the pre 1980 carbs look like? Could you direct me to a picture or maybe a website where I could see the difference between a1979 carb and the 1980-82? I want to verify the one I bought is pre 1980 and won't work on my motorcycle

[Big T]

The top piece of a VM carb has 3 screws, there is an adjustment screw on the side at an angle and one on the underside near the front.
This is a pre 80 carb

The BS (post 80) has a square dome on top, held on by 4 screws.

post up a picture of what you have

[Nessism]

So what do the pre 1980 carbs look like? Could you direct me to a picture or maybe a website where I could see the difference between a1979 carb and the 1980-82? I want to verify the one I bought is pre 1980 and won't work on my motorcycle

Download the service manual at the link provided. The manual shows the differences, which are considerable. You can also go to partzilla or alpha sport and look at the factory parts fishe to see the difference in the parts.

[Dylanblake]

I'll post a pic as soon as I can. But at the top it is only held on by 3 screws, and the intake ports are small. They are kinda "dug" into the carb, and therefore are too small to put into the boots

[jsandidge]

Those are VM carbs... pre-1980.

[Dylanblake]

Thank you for the answer I appreciate it. So there's no way the could work on my bike correct?

[Steve]

The only way those carbs would work on your bike would be to replace the head. Much easier, cheaper, quicker to get a proper set of carbs.

Don't forget that a "new" set of carbs will likely need to be rebuilt before installing them on the bike. Unless you get them from someone who GUARANTEES they they are rebuilt and working properly, plan on doing it yourself or having someone on the forum do them for you. There are several of us that offer that service.

.

[Dylanblake]

Ok thank you for the info. How much does it cost about to have someone on here rebuild them?

[Steve]

The prices I have seen range from $150 to about $200, with varying levels of service offered.

Chuck Hahn (user name and real name) is one that does carbs. Chef1366 is another. I think they both have threads going in the GS Members Parts and Services forum. I had a listing there, but it has gotten lost, I will send a PM on what I have to offer.

.

[Dylanblake]

Ok one more question, so when I bought the bike it was missing one carb boots from the intake. It has the little thing the boot goes on, but the rubber isn't there. So could I just buy the rubber piece and clamp it into the metal thing that's already on my bike? Or do I have to replace the whole setup. I've tried taking the metal piece that holds the boot on off, but the screws are very tight and I'm going to end up stripping it. So if I could just replace the rubbet I wouldn't have to worry about stripping anything

[jsandidge]

You do need to replace the whole thing. The rubber is bonded to the metal part that bolts to the head. Before you order a new one, check all of your others well. If you have any separation or cracking, it will cause an air leak. Air leak = lean condition which will cause poor running and possible damage to the valves.