Petcock Problems

[Guest]

Ok, so I got the electrics working and put new fuel in. However, there is only one rubber tube, and it goes to the black plastic thing that connects the carbs to the airbox. The petcock has two pipes, a large one and a small one. The rubber tube appears too large for either pipe. I don't know which is which, and which one the rubber tube goes to. Even so, I don't see a line to deliver fuel anywhere.

 

[Steve]

Sorry, but until we have at least half a clue what we are working on, there will be no guesses offered.

.

 

[cowboyup3371]

What Steve is saying is what bike are you working on? It would greatly help everyone if you put your bike model and year in your signature block.

One hose will go to the fuel tube in the middle of your carbs while the smaller one feeds the vacuum port on the front of your carbs.

 

[Gorminrider]

and finally,

there is only one rubber tube, and it goes to the black plastic thing that connects the carbs to the airbox.......The rubber tube appears too large for either pipe

and this most likely goes to the top of the valve cover. Look for the large nipple there.

 

[Guest]

Sorry, not used to forums. I try to avoid them, had bad experiences with overzealous moderators and know-it-all/sarcastic members.

My bike is a 1980 GS550E (made 11/79). The title also mentions "UK." I don't know if there are model differences between here and there or not. For example, it only has a single disc brake on each wheel. I've seen others with 2 on the front. It also has no kickstarter. The petcock also appears stuck at a certain point. It points to the left and down, but I try to turn it right (to Reserve), but it won't move.

 

[Guest]

That doesn't really help me. A picture would be better.

 

[Nessism]

The large nipple on the petcock connects to a hose that supplys fuel to the center Tee in the carbs.

The small nipple is for vacuum and connects to a small diameter hose on carb #2 or #3 (can't remember)

Oh, and your carbs look to be in horrid condition. If the bike runs even decently without maintenance you should go straight to the 7-11 and buy lotto tickets.

 

[Guest]

Ok. If you look just under the fuel tank in the picture, you'll see a hose with a wire wrapped around the end. That goes to the plastic thing between the carbs and airbox. So I take it that hose goes to the large pipe?

 

[cowboyup3371]

Right now your petcock is on Reserve. Pointing down is run and pointing to the rear is Prime.

Personally, I can't see which hose you are talking about because of what's still in the way. Can you take a different angled shot?

On a third look, that looks to be the hose that runs from the airbox to the breather cover on the top of the engine

 

[Steve]

Overall, there should be several hoses under the tank.
1. A larger hose (11mm inside diameter) that goes from the top of the engine to the airbox manifold. That is the breather hose that vents the crankcase.

2. A 7mm hose that will go from the larger nipple on the petcock to the T that is between carbs 2&3. That is the fuel feed hose.

3. A smaller hose (4.5mm) goes from the vacuum port on the front of carb #2 to the smaller nipple on the petcock. That is the vacuum hose that pulls the petcock open. Note that carbs are numbered from left to right, as you sit on the bike. #1 is under your clutch hand, #4 is under your throttle hand.

4. There are two 6mm hoses that connect to the Ts between 1&2 and 3&4. Those are vent hoses, they should be routed over the airbox and go through a rectangular bracket that is on top of the air filter box.

5. The last hose goes from the shield around the fuel level sender and gets routed back, over the air manifold and down to below the swingarm pivot. That will drain any fuel away from the hot engine in the event of a gasket leak in the fuel level sender.

Sorry about your previous experience with other forums. We happen to have a pretty good one here. There are no over-zealous moderators. We barely have moderators. We pretty much police ourselves, but there are some 'nanny filters' in force, so there is no foul language that gets posted. There are several that are very knowlegeable about most of these bikes. Sometimes you might detect a bit of an attitude, but that might go away with the presence of coffee at one end or the other. Your worst 'offense' so far has been the great delay in telling us what bike we are playing with. Like I said, collectively, we know virtually everything about these bikes, but something as simple as the changes from a '79 550 to an '80 550 would change the suggestions that we would need to offer. A 550 also does things differently than a 750 or 1000, and they all do it differently than a shaft-driven bike.

I don't know as many details on the 550s as I do on some other models, so I can't say if any of them had two discs on the front. I know that some 650s and larger bikes did, just don't know if any 550s had two. All GSes lost their kick starters with the '80 model year. There was also a change to a different carburetor and charging system, so your bike was 'blesssed' with the newest versions of all those.

As was already mentioned, in the last picture that you posted, your petcock was not stuck in between positions, it is fully in the REServe position. With the lever pointed down, it would be in the RUN position. With the lever pointed back, it would be in PRIme. Unless you are actively filling the float bowls, do NOT leave it in the PRIme position for more than a minute or two. The only thing that would hold back fuel would be the float valves in the carbs, and yours look sketchy enough that I would not trust them.

.

 

[Guest]

Right now your petcock is on Reserve. Pointing down is run and pointing to the rear is Prime.

Personally, I can't see which hose you are talking about because of what's still in the way. Can you take a different angled shot?

On a third look, that looks to be the hose that runs from the airbox to the breather cover on the top of the engine

I'll take a new picture tomorrow. Breather cover?

 

[Guest]

Overall, there should be several hoses under the tank.
1. A larger hose (11mm inside diameter) that goes from the top of the engine to the airbox manifold. That is the breather hose that vents the crankcase.

2. A 7mm hose that will go from the larger nipple on the petcock to the T that is between carbs 2&3. That is the fuel feed hose.

3. A smaller hose (4.5mm) goes from the vacuum port on the front of carb #2 to the smaller nipple on the petcock. That is the vacuum hose that pulls the petcock open. Note that carbs are numbered from left to right, as you sit on the bike. #1 is under your clutch hand, #4 is under your throttle hand.

4. There are two 6mm hoses that connect to the Ts between 1&2 and 3&4. Those are vent hoses, they should be routed over the airbox and go through a rectangular bracket that is on top of the air filter box.

5. The last hose goes from the shield around the fuel level sender and gets routed back, over the air manifold and down to below the swingarm pivot. That will drain any fuel away from the hot engine in the event of a gasket leak in the fuel level sender.

Sorry about your previous experience with other forums. We happen to have a pretty good one here. There are no over-zealous moderators. We barely have moderators. We pretty much police ourselves, but there are some 'nanny filters' in force, so there is no foul language that gets posted. There are several that are very knowlegeable about most of these bikes. Sometimes you might detect a bit of an attitude, but that might go away with the presence of coffee at one end or the other. Your worst 'offense' so far has been the great delay in telling us what bike we are playing with. Like I said, collectively, we know virtually everything about these bikes, but something as simple as the changes from a '79 550 to an '80 550 would change the suggestions that we would need to offer. A 550 also does things differently than a 750 or 1000, and they all do it differently than a shaft-driven bike.

I don't know as many details on the 550s as I do on some other models, so I can't say if any of them had two discs on the front. I know that some 650s and larger bikes did, just don't know if any 550s had two. All GSes lost their kick starters with the '80 model year. There was also a change to a different carburetor and charging system, so your bike was 'blesssed' with the newest versions of all those.

As was already mentioned, in the last picture that you posted, your petcock was not stuck in between positions, it is fully in the REServe position. With the lever pointed down, it would be in the RUN position. With the lever pointed back, it would be in PRIme. Unless you are actively filling the float bowls, do NOT leave it in the PRIme position for more than a minute or two. The only thing that would hold back fuel would be the float valves in the carbs, and yours look sketchy enough that I would not trust them.

.

Thanks for explaining it in more detail. I am autistic, and some things that other people would instantly get, I may need more information.

It would appear I am missing a couple of hoses then. There's only the one that goes to the plastic box, and I have to find where that goes. And as for the fuel selector, thanks for fleshing that out. Then it won't go to Prime. It stops just after Run. I tried opening it, but one of the bolts is stripped out.

 

[Steve]

Thanks for explaining it in more detail. I am autistic, and some things that other people would instantly get, I may need more information.

Thanks for sharing that. That is one thing that might not be noticed in-person, and would REALLY not be noticed via the internet, so it's nice to know. Some of the more-knowledgeable people here might not always take the time to explain the details, but I try to explain, at least until my victim says "OK, I know that part".

And, a THANK YOU for the signature. :encouragement:
Basic, simple, tells us what bike you are working on.

A few words of advice: some things, like fuel hoses, you will not find at the auto parts store. For example, the main fuel hose is a thin-wall, non-reinforced 7mm hose. Virtually everything you will find at Auto Zone will be in INCH sizes, as well as thick-walled and re-inforced to handle the pressures of fuel injection. If you look at the parts fiche, you will choke at some of the prices, but you have to keep in mind that the $10 for the fuel hose actually gets you a hose that is about six feet long. The breather hose also comes in a longer roll. The other hoses seem to come pre-cut, so their cost is just for that length. Expensive? Yes, but it's the right stuff, so it's worth it.

.

 

[Guest]

I'll post some more pictures tomorrow in the daylight for clarity, and you can see what I'm missing.

 

[Guest]

Top

 

[Guest]

Side. There is a second hose.

 

[Guest]

Side again, second hose exposed (the tip is visible just above the plastic air intake, right near the frame).

 

[Guest]

Thanks for sharing that. That is one thing that might not be noticed in-person, and would REALLY not be noticed via the internet, so it's nice to know. Some of the more-knowledgeable people here might not always take the time to explain the details, but I try to explain, at least until my victim says "OK, I know that part".

And, a THANK YOU for the signature. :encouragement:
Basic, simple, tells us what bike you are working on.

A few words of advice: some things, like fuel hoses, you will not find at the auto parts store. For example, the main fuel hose is a thin-wall, non-reinforced 7mm hose. Virtually everything you will find at Auto Zone will be in INCH sizes, as well as thick-walled and re-inforced to handle the pressures of fuel injection. If you look at the parts fiche, you will choke at some of the prices, but you have to keep in mind that the $10 for the fuel hose actually gets you a hose that is about six feet long. The breather hose also comes in a longer roll. The other hoses seem to come pre-cut, so their cost is just for that length. Expensive? Yes, but it's the right stuff, so it's worth it.

.

Alright, pictures are posted. What do you think? I found a second, shorter hose that runs to the rear of the carb (closer to the airbox than the engine). I also found a pipe similar to one on the petcock that's on the front of the carb (closer to the engine). And I am unable to turn the petcock selector to Prime. It stops moving just past Run.

 

[cowboyup3371]

You are missing your fuel and vacuum lines from the petcock to the carbs. That hose with the clamp definitely goes to the breather cover (you'll see the corresponding plug) on the top of the engine.

It looks like that entire engine has sat outside for decades and been subjected to major weathering. At the very least, pull your carbs off and properly disassemble and clean them per Nessism's tutorial on Basscliff's website - http://zeus.mtsac.edu/~cliff/storage/gs/Mikuni_BS-CV_Carburetor_Rebuild_Tutorial.pdf

New vacuum hose from Parts Outlaw - HOSE (part number - 09355-45855-600) $8.38

New fuel line - HOSE, FUEL (L:250->140) (part number - 09352-70104-00B) $10.04