float height

[Mikhail]

OK guys, just wanted to share - Im finally done with setting the float level and I made myself a good tool out of LEGO. Perhaps someone might find it useful. The width of a "1 by x" LEGO brick is 7,8 mm, which is a good measurement to setup your float.

1) place the carb horizontally, so that the float hinge is up and float is hanging down. start slowly rotating the carb, until the tang of the float rests on the needle valve without compressing the spring.

2) doublecheck, that needle valve is closed in this position and that spring inside the needle valve is not compressed - do that by pressing the floats lightly and make sure there is no movement of a needle valve, but you should see a spring action, as the tang presses against the spring.

3) apply the LEGO tool to both sides of the float, by pressing the white bricks on the carburetor edge of the float chamber.

If the float is in position described in #1 and your float highest point is just touching the blue LEGO plate (without compressing the spring], your float level is good to go and is set precisely to 7.8mm from carb body to the lowest float edge.

I have personally set to approx 8.0 - 8.2 mm (meaning when LEGO gage applied, the float was compressed by cca 0.2-0.4 mm) and riding is good.

Maybe this might help someone.

[Addicted]

I actually thought the vent lines (yes those can be routed to the airbox) are not the same as the overflow line, which is there to make sure that due to bumps, vibrations and bike tilting, the float level is still maintained below maximum threshold (excess fuel is spilled out) not to overflow the bike with too rich mixture.

If I make a loop as per picture posted in another thread - dont I disable the function of overflow hose?

Yeah, I agree. Looping the overflow up isn't smart. My new XT overflow line dripped for the first day I owned it, then I lowered the float level about 1mm on the farthest edge from the hinge pin (0.5 if you measure in the middle of the float). Seems to have stopped the dribble. Now I need to re-Jet the bugger so it will run a little better.

[markbxr400]

Just bought an 18 Xtrainer while out in Colorado (1700 miles away) earlier this week. Haven't ridden it yet, but notice the dreaded fuel/oil mix dripping out the overflow. Any trick to bending the tang on an 18, i.e.., guessing I just want the float to seal off slightly earlier?

[njbill]

Just bought an 18 Xtrainer while out in Colorado (1700 miles away) earlier this week. Haven't ridden it yet, but notice the dreaded fuel/oil mix dripping out the overflow. Any trick to bending the tang on an 18, i.e.., guessing I just want the float to seal off slightly earlier?

See my post in the Xtrainer jetting thread. I did not have to take the carb off to remedy this AND greatly increase my mpg.

[markbxr400]

Will do. Thx

[Superboar]

As per the instructions that came in the owner's manual, my float height is is very close to spec, but I am getting 16 MPG on my new 2019 300rr. I'd have to be way aggressive riding in deep sand to believe that all the fuel flowing out of the tank is actually being burned; I am neither!
So where is it going?

[mtdirtbag]

It's going out the overflow tube. When I pulled my carb down to inspect, it looked very close to what Beta spec'd it at. I lowered the float height a small amount and increased my mileage to the point that I could have stayed with the stock tank. By the way, the manner in which I lowered it was not in a measured amount - I just eyeballed it.