I copied and pasted this from DBW, it's from Duckman (aka, Scotty's Dirt Bike Spares) who is one of Australia's premier GG dealers. Second paragraph refers to float level.........
We ran a stock 2010 EC 300 this year in the Vic off road series ( and 2 modified ones) the bike ended up 2nd in expert open. Russell would off won the year had he not been a no show at the last round while he was overseas. The bike was box stock except for a FMF TC muffler, Dirtworks Suspension/Main Jet Motorcycle modified (harder) forks and the shock had the oil changed, thats all. We used the N3EJ (Yamaha) needle on the 3 rd clip, 42 pilot and 175/178 main. The air screw will settle at about 1and a half to 2 out. The other 2 bikes had head squish modifications which require richer jetting.
One thing you must do is reset the float height lower than stock. This isn?t rocket science and you don?t even need to remove the carbie from the bike to do it. Remove the sprocket cover. Loose the carbie manifold and airboot clamps tilt the carbi top towards you remove the top cap and slide. Swing the carbie the way pulling the overflow hoses through. Remove the 4 bowl screws and bowl. Simply bend the float tag in/up a little. At stock float height the arms of the floats usually end up parallel with the body of the carbie and fuel flow will stop. You need to get the fuel flow to stop with the float arms about 10 degree from parallel. To check you got it right fuel should only start to spill out the overflows when the bike is 45 degree to the ground not sooner or later. Its allot easier to do than trying to explain it in words. Don?t do any jetting without doing this first it makes all the difference. If you brought your bike new from us we have already done it.
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