TOPIC:

loudhvx wrote:

If the question is: will the flost level change when the carb is at a different angle?

Well, what is the level referenced too?

Where do you define the fuel level?

Usually, the carb/bowl gasket is a reference point for the fuel level, but if the carb is at an angle, that reference is no longer available.

So what, then, would you use as a fuel level reference if the carb is at an angle?
Would we use the volume of fuel in the bowl?: The volume in the bowl is really not important. The purpose of having a consistent level of fuel is to have a constistent hydrostatic fuel pressure on the jet openings. Volume does not affect pressure. Depth of the jet below the fuel surface determines the pressure.

Would we then use the fuel level relative to the main-jet opening? Do we really want that to be the same for different carb angles? Not necessarily. At higher angles from horizontal, fuel will have less gravity to fight in order to travel up the emulsifier tube so the pressure on the jet aperature need not be as great.

It is possible to create a bowl shape such that the jet is always the same depth in the fuel, but I'm not sure that is what would be desired. It seems you would want the jet aperature to be shallower as the carb angle increases.

I haven't really studied this that much, and this is all a bunch of speculation on my part, but just thought I'd throw out some possibilities.<br><br>Post edited by: loudhvx, at: 2007/02/13 03:14

Thanks, loudhvx for all the info, I think
oh yea, and welcome to the site.
I am afraid I have a much more simplistic idea on what I want as the service fuel level.
On all carbs I want the maximum fuel height/depth without fuel leaking out of my overflow tube.
The reason I went into them in the first place, is because I did in fact have a trace of overflow fuel.
I would also think it logical, that bowl levels on all 4 carbs be as close as possible to same.
I do not have any concern for the level changing as a result of changing carb angle. Should I?
After observing where the overflow tube is situated, like, 5mm or so above top of bowl, then I am reasonably confident that the only problem angle for your carb would be like, upside down. Even that is not a big deal unless you happen to still be on the saddle at the time.

Post edited by: JimatMilkyWay, at: 2007/02/14 01:43

loudhvx wrote:

.... the carb/bowl gasket is a reference point for the fuel level, but if the carb is at an angle, that reference is no longer available.

So what, then, would you use as a fuel level reference if the carb is at an angle?
....

When you are in a high speed turn with the bike leaned close to the pegs, the fuel level in the bowl may not change as much as one might initially think .
Any of youse guys ever do student, err that is stunt flying? You can do a loop and, if done properly, when the plane is upside-down, the water will stay put in the cup, and I am not useing a sippy cup. Well maybe when me and the little lady gets kinda frisky, but that's for another, different kind of forum.
I expressed concern over the fuel level changing with carb angle _before_ I removed the bowl and saw how high the overflow tube extends above top of bowl. My primary concern now, is whether or not my float needle-valves are totally closing off flow.

Post edited by: JimatMilkyWay, at: 2007/02/14 09:26

Oops, by "angle" I meant like going up hill or down hill, in which case the gas will slosh to the back or the front of the bowl, but since the jets (and the overflow pipe) are near the center, the level at that point shouldn't change too much.

loudhvx wrote:

Oops, by "angle" I meant like going up hill or down hill, in which case the gas will slosh to the back or the front of the bowl, but since the jets (and the overflow pipe) are near the center, the level at that point shouldn't change too much.

Thanks loud. I agree with you about angle related fluctuations in the bowl-fuel-level causing little or no real effect on performance. Especially so,now that you pointed out the central location of the jets and overflow pipe "in" the bowl.

loudhvx wrote:

Oops, by "angle" I meant like going up hill or down hill, in which case the gas will slosh to the back or the front of the bowl, but since the jets (and the overflow pipe) are near the center, the level at that point shouldn't change too much.

Actually in my TM33´s the main jet is inside an aluminun tube about 10mm long. The jet is a normal Mikuni jet which is inserted into the tube and then screwed into the carb body. This will help main jet not to suck air when accelerating or braking heavily. Should also work on wheelies:P