TOPIC:

SWest nailed it.

Your petcock is vacuum operated, and that vacuum is supplied by the suction drawn through the #2 carb when the #2 piston is cycling up and down. If fuel is flowing from the tank with the petcock in the "run" position and the engine shut off the petcock has a problem that needs to be addressed. Ed

Didn't know that. So if the petcock is in one of those two positions, I can disconnect the fuel line and fuel will not drip out?

Yes, you should be able to, but keep in mind that the engine's poor could be caused by a faulty petcock allowing fuel to flow through the vacuum line into #2 cylinder.

If it was mine I would put the petcock in the "run" position and disconnect the vacuum line. For sure not a drop of fuel should come from it. If fuel does drip from the vacuum line there is a problem with the petcock. Assuming no fuel drips from the vacuum line I would then disconnect the fuel line. Again, no fuel should flow from the tank. If it does there's a problem with the petcock. I wouldn't cut the fuel or vacuum lines because if fuel does flow you want to be able to reconnect the lines quickly. Ed

Sincerely, thank you to everyone helping with this. I'm learning a lot about this bike from just this thread. I have the Golan and new fuel line in my shopping cart, but that's going to have to wait until after my wifes birthday present gets ordered. Happy wife, happy life

I have a theory, wondering if it makes sense. Lately the more frequent backfires when I lay off the throttle can be attributed to a clogged jet not vaporizing fuel properly, so the liquid form works its way down in the exhaust. So when I clean the carbs, the backfires will cease. Or am I just crazy?

With a perfectly clean pilot circuit, correct fuel level and correct pilot jet -- like when the bike was new -- there should be no exhaust popping when decelerating. The remedy is sometimes by slightly enriching the pilot mixture. Which can be done by turning the pilot air screws slightly clockwise to reduce the air and thereby enrich the air-fuel mixture.

Good Fortune!

Has anyone ever seen a section-drawing of the RS Flat Slide series carburetor which shows the circuits in similar detail?

Thanx!

Hey 650ed, could I twist your arm into putting up a picture of what your fuel delivery setup looks like on the bike? Knowing what the puzzle should look like will help me know what I'm doing

pa317 wrote: Hey 650ed, could I twist your arm into putting up a picture of what your fuel delivery setup looks like on the bike? Knowing what the puzzle should look like will help me know what I'm doing

The reply I gave near the beginning of this thread describes the components I use. The images below show how I have them assembled. I hope this helps. Ed

Thank you for the pictures. I did take the bike on my commute to work yesterday. Sometime after putting it in the garage, some fuel hit the garage floor. Enough that this morning, I would not have wanted to work in the garage without venting in fresh air first. It looks like it came from the overflow tubes. The choke lever was not turned all the way off. I'm guessing this is not normal and I have something else going on in addition to some clogged jets

That would affect idle.
Steve

pa317 wrote: Thank you for the pictures. I did take the bike on my commute to work yesterday. Sometime after putting it in the garage, some fuel hit the garage floor. Enough that this morning, I would not have wanted to work in the garage without venting in fresh air first. It looks like it came from the overflow tubes. The choke lever was not turned all the way off. I'm guessing this is not normal and I have something else going on in addition to some clogged jets

Fuel escaping through the carb overflow(s) is often due to imperfectly sealing float valve(s).

The overflowing may usually be avoided while parked by turning a properly functioning manual petcock to OFF or by turning a properly functioning vacuum petcock to either ON or RES.

Sometimes, running some carb cleaner in the fuel can help clean the float valves and help restore proper operation of the float valves.

An after-market in-line fuel filter is also helpful toward keeping unwanted crud and grit away from the float valve.

Good Fortune!