78 GS 550E carb questions

[Guest]

Hi all....if you followed my 78 550E points issues in the electrical section, this is the same bike. Finally got it all sorted out and cranked her up...and she ran really good up and down the street. Much better than I thought she would. But there are a few carb issues. And for background on these carbs, they were completely taken out, dipped, cleaned and put back together with new o-rings so we're good there. This was my 4th set of carb rebuilds.

1) Number one carb drips gas out of the overflow tube and I'm thinking it's a stuck float. All the floats were measured and set to specs, but I was wondering if it could be anything else.

2) And this is my most curious issue...when she first fired up she ran pretty rich. I went about adjusting the air/idle screws. Turning them out made her run worse and turning them in made her run really, really good. The best running position was with the air/idle screws closed all the way..which seems odd to me. Anyone have any advise on if having these screws turned all the way in is okay or bad? The pilot jets were set one turn out and the air/idle screws were turned out 1 1/4 to begin with.

Thanks...these are VM carbs.

[Guest]

Oh and I forgot, she's completely stock!! No pods or mods in any way.

[Suzuki_Don]

SUPER, when you say the pilot jets are 1 turn out, do you mean the fuel screws underneath the carbs or the actual pilot jets inside the carbs? Pilot jets inside the carbs should be done up tight.

[Guest]

I mean the pilot jets inside the carbs. According to the rebuild guide I used it stated to turn them out 1 turn. If they should be tight then that would explain a lot.

[Suzuki_Don]

Super, the pilot jets should be tight as are the main jets, etc. Check your pilot jets are the correct size as it is unusual to say the least to have the air screws all the way in to get the motor to idle decently.

If after tightening the pilot jets the motor only runs sweetly with the air screws all the way in then I would cut the fuel back to the idle circuit by screwing the fuel screws underneath the carbs in to about 3/4 of a turn out from being bottomed instead of the 1 turn out you have at the present time. Then readjust the air screws. I think the instructions you read might have said to turn the Fuel Pilot Screw out 1 turn, not the pilot jet. The fuel screws should typically be between 3/4 and 1 1/4 turns out.

The only other issue that may be present is a blockage or blockages in the pilot circuits if the carbs, another clean if all else fails. Make sure you blow all the passages out with compressed air after squirting with carb cleaner. If the carb cleaner does not come out of another opening when squirted into the carb passages then you have a blockage somewhere.

[Guest]

Suzuki Don...you are the man! After re-reading my rebuild guide I see where I screwed up. It thought that the backing out of the the pilot fuel jet meant backing out the bleeder pilot jet.

I will double check these as that is where I messed up. On the other 3 carb rebuilds I did, the pilot jets were screwed tight...but they were CV carbs. It did stand out in my mind that I didn't back out those pilots but I thought that these are VM carbs and they are probably different.. but despite this mix up, she ran unbeliveably good!! I can only imagine how she will run when I get the carbs right.

Thanks again and I will post an update. It may be a few days though as it hit 97 degrees today and I work outside so I'm a bit wore out.

[Suzuki_Don]

Suzuki Don...you are the man! After re-reading my rebuild guide I see where I screwed up. It thought that the backing out of the the pilot fuel jet meant backing out the bleeder pilot jet.

I will double check these as that is where I messed up. On the other 3 carb rebuilds I did, the pilot jets were screwed tight...but they were CV carbs. It did stand out in my mind that I didn't back out those pilots but I thought that these are VM carbs and they are probably different.. but despite this mix up, she ran unbeliveably good!! I can only imagine how she will run when I get the carbs right.

Thanks again and I will post an update. It may be a few days though as it hit 97 degrees today and I work outside so I'm a bit wore out.

Well it is only 16 here today so I envy you a bit. Which rebuild guide did you use? Was it the VM carb guide off the GSR site?

[Guest]

Yep..that was the one. I just some how overlooked the wording in regards to the pilot jet..totally my fault. I love working on carbs and I was getting near the end and just got a little too excited to finish them. 16 degrees?...wow.

[Guest]

Okay...I don't think the internal pilot jets were the issue. I pulled the 2 outside bowels on carbs 1 & 4 and both of those pilot jets were screwed all the way in. So I have to believe the 2 & 3 internal pilot screws are also correctly screwed all the way in, since I was the one that rebuilt them.

That puts me right back where I started this thread. The bike kicks over on the first kick and runs really well through the first 4 gears (that's as far as I got up and down my street...don't trust the tires) and yet to get it to run like that I had to turn the air/idle jets all the way in??? When I backed them out it runs worse?

Could I possibly need to adjust the other pilot fuel screw, the one on the bottom of the bowl? Right now it's at 1 turn out. Maybe if I back them out 2 turns and see how she runs? And then try adjusting the air/idle screws?

Any help would be appreciated. Thanks

[Suzuki_Don]

Super, these carbs are sensitive to small adjustments. I would back out the fuel screws 1/2 a turn and see how the motor runs like that. If it's blowing black smoke then I would back the Pilot air screws out about a turn and see what difference that makes. That way you should be able to get it running OK. At the present time you seem to have run out of adjustment on the air screws. On 2nd thoughts only back the fuel screws out another 1/4 of a turn. If you look at page 5 in the tutorial under Pilot Fuel Screws you will see the standard from the factory was between 3/4 and 1 1/4 turns out from fully bottomed out. So another 1/4 turn out would put you at 1 1/4 turns which would also allow the Pilot Air Screws to be turned out a bit.

[Guest]

Okay ...I will give it a shot. It seems to be the logical next step. I may have been too quick to adjust the air screws after getting her running the first time I cranked her up. I just can't get over how well she ran, but I feel uncomfortable having the air jets completely closed.

I appreciate the help and will let you know how it goes. Has it gotten any warmer there? It was high 90's here again.