Float Level, please explain?
 

I asked this question on another site some time ago and got no response, it was either a stupid question or nobody actually knew the answer?

The way i see it the floats in your carby are no different than the floats in the cistern of your toilet, set them too high and you'll have overflow issues but flushing turds isn't a problem, set them too low and your bike may be starving of fuel and in the case of a dunny, you can't flush your turd.

Back to the bike scenario, provided the bowl is full of fuel, even if it's overflowing, the bike should run OK shouldn't it ? Won't the various jets just take the fuel thay need via their orifice's and the overflow tubes disperse the rest.

I can see how not enough fuel in the bowl could cause lean jetting issues.

But why is there so much talk about setting float levels, did GG or keihin have it so wrong?

What is the correct float height? I've read for the old screw top keihin it's 16mm, but what about these new style carbs, when i roughly measured mine recently it was about 10mm max and i left it as found. (2010 ec300)

My bike runs pretty good in my opinion, i just get frustrated when i read on some of these sites people saying "make sure your float level is set right".

The point of this drawn out spiel is HOW & WHY?

PS: I'm an aussie, most of you probably are not.
I can't understand why you put the month before the day,it gives me the shits. Very hard to follow your calenders.
Dunny= Toilet
Turd= Poo.

This has been discussed in another thread. No spec as of yet, but I'd say set it so it closes with the float level which is 16mm on the old carb. Do a search and you will find this and the procedure.

Changes in fuel level in the carb bowl change pressure on the jetting, changing mixture.

Why would float levels need to be adjusted from new?
I feel no need to adjust mine, i just can't understand why some people say "make sure your float level is right" when nobody knows what right is.

If the fuel level is too high it will also slosh through the jets and air orofices into the engine. The overflow tubes can't always handle all of the overflow.

Float levels should at least be checked when new because like most everything else these days it's probably a 8yr old indonesian kid assembling the carb (OK, that may be a little exaggerated) but the point being with so many of these carbs being mass produced there is no way more than about 20% off the production line (in my opinion) could be considered perfect. So some will slosh fuel and most people won't even know. Some will be lean and contribute to early engine failure (and the owner still may not know the float level was a contributing factor). Engine manufactureres (not only GG) are pushing the limits to squeeze out every last horsepower available. In doing so these "minor" adjustments become much more critical for engine performance and longevity.

good idea
 

After reading this I am thinking I will check mine.

My bike (just got it) does some times spit out fuel when I have it on the kickstand, making me think that the bowl is too full.


thanks

Rod. Float levels are set high so that the guy riding his ec 250 on the autostrada, autobahn, whatever at 120kph does'nt starve the engine for fuel. A lot of these bikes never see dirt. Now if your the manufacturer would you set the float level at a safe high level for the street guys and let the off road guys tweak the carb, or vice versa. The guys at the factory are going to assume, correctly that a reasonable thinking owner of a new bike is going to spend the time to race prep it properly. And it's just as simple as that. As a second point to confuse matters even more is ,what is right? Right should not be confused as a subjective term, right for you may not be right for me. Right should be viewed objectivly as scientificly correct for the application so in this case lets assume right is in the case of enduro type riding, lots of up's and downs and sustained lean angles. Another definition of right , a subjective one could get you steered in the wrong direction, an example being, you would'nt want to use Jimmy jumpers right to him suspension setup if your not jumping
Right?

Rod,

Your interesting analogy is pretty close! :D
It can be a little too rich at idle/low rpm when overflowing as the fuel doesn't need to be lifted so far and only tiny amounts of fuel are being demanded. I don't think it effects running at open throttle/ high rpm because the suction with lots of fuel flow is so great a couple of mm difference in fuel height doesn't matter.

The reason I think there is so much chat about float height because there is not much difference between overflowing and running short of fuel WFO especially on the 300. I can't remember which way round it was but I remember finding the Keihin recommended level didn't work for me. I set it to the point it just stopped overflowing.

The float height can also contribute to "bad fuel mileage" by letting the bike piss the fuel out of the overflow tube when the bike leans, goes up or down a hill, or just lets extra fuel into the crankcase when it doesn't need it.

It is easy to set the float level. The hard part is taking off the four shitty pot metal screws on the float bowl and not stripping them out with the screwdriver.

I had a KDX years ago where the float was too high. At idle and coasting the bike would load up. I kept going leaner on pilots, needle, air screw, until it bogged badly when I opened the throttle up. The problem turned out to be the float. Jetting was very lean, however was masked by the "flooding" that was happening due to the float height being waaaay too high.

Fixed that and the bike ran good.

Along with what is the correct height for the float level, where do you measure it from (or what is the point of reference you use)?

Just want to make sure we are all using the same point of reference when the numbers are being thrown out for use. If someone has a drawing to post it would make sure the ones who are unsure are getting the correct information.

The sticky at the start of this forum will spell it out, the 14-16mm suggested is for the circular screw top carb. I'm not sure when GG went to the newer style carb (2 x small screws holding down carb top). My 2010 ec has this newer carb and so does 2011, the jury is still out on this one as far as recommended float level goes, but i wouldn't be using the old specs of 14-16mm.