vm 20 carb, aero 125 scooter

[bob]

Simple question, not sure of the answer.
This line of carb shows LITTLE illustration or tuning specific guidelines in order to make it work. I changed mains and idle jet, ran "good" i suppose. I shut it off and it ran out the float overflow tube. I cleaned everything and tried again..way worse. Out the overflow and the vent.
In the process I had changed the gasket on the banjo to the float bowl. It was an oring but it split.
I replaced it with a hard gasket. Is that what caused it???

[Rebel]

might be what is causing the leak, you may have been running a bit rich if it started flowing out the overflow after you turned it off.

[bear4570]

Two problems if not three. With the engine off the automatic petcock is suppose to stop the fuel flow to the carb, it isn't. That is problem #1. The needle and seat is suppose to close and stop the float bowl from over flowing, it isn't. That is problem #2. The flange leak is either a gasket/o-ring problem or a warped carb body or float bowl. I am not a fan of the Mukuni carb and a 20 over the stock 18 mm carb is gonna provide very little performance increase. You have to do "plug chops" to determine if you fuel/air mixture is correct.

[Rebel]

Bear is looking at the big picture there, take his advice.

[bob]

I am humbled, he is the man:)
The petcock IS the immediate problem. The second is, do I bend a one piece float??
I get all of that, I am really just a complete geek when it comes to little things I dont or cant see.
Main reason I wanted to see if anyone new the vm carb series.
I Know that the main jet butts against the float bowl outlet for the needle jet, (it is esentially the gasket between the bowl and the main). The hard gasket pulled the main from sealing the bowl from the needle jet. It set them both off.
Im sorry if I dont explain things very well, I am just stuck..

[Rebel]

my experience with bending floats is that if you do not have the proper gauge to adjust it with you are playing with fire. I'd fix the valve and get an O ring before I took a blind stab at adjusting the float.

[bear4570]

Jun 24, 2012 22:45:52 GMT -5 Rebel said:

my experience with bending floats is that if you do not have the proper gauge to adjust it with you are playing with fire. I'd fix the valve and get an O ring before I took a blind stab at adjusting the float.

I agree.

[bob]

As a preemptive strike, I have a link to Scrappy Doggs. I know I need the petcock but they dont make them for my scooter anymore. If you know which one to get, it would save me the time, and my room mates yelling about fuel on the dw)
I have the oring, and it is in. so far so good.

[Rebel]

If you can post a photo of the petcock we might be able to find one for you to order. What a lot of people do is just get a manual petcock from a lawn mower and plumb it in, it takes a little creativity to rig up but it works and you no longer need to rely on the vacuum, you just have to remember to turn it off and on.

[bear4570]

According to Honda they still sell the Aero 125 petcock.

PETCOCK, AUTOMATIC 16950-KG8-901 (replaces 16950-KG8-003) $43.13

[bob]

OK, Thank you for the help, I was really tearing my hair out.
i found an oring that fit, it stopped my float bowl leak.
I totally agree that the 18mm carb was a much better fit btw..problem was the bystarter didnt work and I couldnt find one. The mikuni works pretty good but I did loose a little high end. This 20 mm didnt fit very well so I ended up having modify the air box a little to make it work. That float problem threw me but Im back on track.
After it was done it was running lean due to the airbox mod, so I put the 200 jet back in it, and presto, Im riding:)
Again thanks for the help, I am ordering the petcock tomorrow, That should be the ticket.

[Rebel]