'83 550: Leaking Fuel, Can't Idle

[DR Payne]

This happens from time to time, meaning maybe 10% of the trips I take. I thought it was one of the connections between the tank and the carbs, but refreshing those doesn't seem to have done it. I can't figure out where the leak is coming from, but I'm starting to wonder if it's actually from inside the carbs?

So does this sound familiar to anyone? It starts dripping gas from the carb area, and in the worst cases, it will no longer hold idle. It just dies. I can easily restart it and keep it running by holding the throttle open, it drives completely fine, but once I let the revs drop below 1.5K or so, it just stops. Does this sound like fuel not getting to the carbs because it's leaking, or fuel coming FROM the carbs and flooding them at low revs? What makes more sense, given that it runs and drives just fine as long as I have the throttle open?

Thanks for any hints, hoping to narrow down my search for when I have time to test it.

[Nessism]

http://www.thegsresources.com/_forum/showthread.php?t=171846

[DR Payne]

I don't see anything there related to my question. Perhaps you should ad it.

[dgates1]

I'd check you float bowl gaskets. Forgot to tighten the screws on one bowl one time and created a leak while running.

If you haven't fully gone through your carbs... and did it well. You need to.

From Ed's Signature --->> Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

[Nessism]

I'd check you float bowl gaskets. Forgot to tighten the screws on one bowl one time and created a leak while running.

If you haven't fully gone through your carbs... and did it well. You need to.

From Ed's Signature --->> Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

It can't hurt to read through the tutorial, even though the carbs in question are somewhat different. Many of the O-rings seem common with the other Mikuni CV carbs.

[salty_monk]

My first try would be to put a high dose of SeaFoam in the tank and run it... see if you can cure it that way. My guess is that you have blocked passages in the carb and/or one of the float valves is stuck or something,
They will be due a clean & O-ring replacement if you haven't done so already.

Being a *@%^$*@%^$*@%^$*@%^$ to Nessism is not a good way to get help round here... he is one of the most knowledgeable members we have (and likely stocks the O-rings you might need on his shelf - you generally have to buy them in big quantity.

[Cipher]

Replace fuel tube o rings
remove float valve seats replace o rings. A royal pain with mangly brass the seals fail and allow fueul to bypass the valve. Happened to me.
check petcock function
check float bowel drain bolt seal and gaskets
maybe a dye would help isolate

[roeme]

I don't see anything there related to my question. Perhaps you should ad it.

I'm going easy on you, since you're a Newbie. Quite a few things apply actually.

In any case, you need to do maintenance on the carbs.

I'm only here sporadically, and the Forum won't let me view your complete posting history. So, what's your wrenching experience? What do you know about the bike? Were the carbs ever off?

[DR Payne]

OK, so it sounds like the consensus is that this actually could be a carb problem, causing gas to flood out from them at idle but run fine under throttle? I suppose that does make more sense intuitively than an external leak starving the carbs of gas which might imply the reverse: they'd idle fine, but not have enough gas to run under throttle. Still, I'm pretty sure everything is tight from the tank to the carbs, so I'm not hesitant to believe this is an internal carb problem.

That is all the information I was looking for here. Apologies if that was not clear in my original post.

[roeme]

From the limited information you have provided it's the most likely explanation, but you won't know for sure until you have established an "known good baseline" with that bike.

I've found your previous posts and saw that you're no stranger to work on bikes and on that one in particular, but I saw mainly electrical work, nothing on the carbs yet.