1999 CR250 R . Adjusting the float.....

[RedFoxCR]

well, so, here's the problem. I have a 1999 CR 250 R after installing a new

piston kit. When i started it i felt something wrong with the Carb. For example,

 it would work pretty well in mid RPM, but when it was given a full throttle or

near,  it would blast a huge cloud of smoke and loose power at the first

moment, then OK, but still with lots of smoke.It was probably due to too high

fuel level, so i lowered the float a bit. After that, there wasn't any smoke in all

RPM range, but the power remained noticeably low.
Then i pulled out the slide and moved the needle UP, by lowering the clip, in

order to enrich that stuff. Before the adjust, the clip was in the 2nd position

from the top (i have five positions). I moved it 2 positions down, to the 2nd

position from the bottom. And went for a ride.
That adjust resulted in a horrifying burst of power at some point around the

throttle half-opened. It was unexpected and i rode in an uncontrolled wheelie

for a few seconds. But when hit the gas to the max, i felt the power slightly

reducing on a full-opened throttle. And very little smoke came out at fully

opened throttle.
I decided to get some more fuel and blocked the pipe on the top of the tank

with a screw, like some american riders do.  That caused the fuel to squeeze

through the carb valve because the increased pressure in the tank. That made

the things a bit better, but the engine is now working very loud on high RPM

and makes a high jingling sound, like if there is little oil. And it now doesn't

wheelie so easy.

I run "Normal" petrol, in our country it's called AI-92, mixed with synthetic oil

1:32 like it is said in the manual.
I can upload the video, where the engine sound is clearly heard, if that helps.

So,how to deal with this??? :| is it because of the lean mixture at the top??? It

would be kind of ya if you explained me how to set a proper full level.

[ford832]

Um,I'm not sure where I'd start here.For one thing,set your float to the proper height-or a tad higher-like I do.Secondly,you're making way too many changes between rides-ie-just one clip position at a time and change nothing else until you try that.Thirdly,are you talking about blocking your vent hose? Fourthly,now that I reread,you're not yanking our collective chain are you?

[RedFoxCR]

About the vent hose. I recently heard that helps. 
So, how can i see if the float level is OK? One guy suggested to put the opened carb onto a glass jar and make the gas flow down. When the float comes up, the valve closes and the fuel level remains constant. Is there any easier solution? Without a jar and gas spilling everywhere?

[RedFoxCR]

Will you please help/?

Imagine, the bike accelerates VERY SMOOTHLY a second after a full opening! Is that normal?? I wanna wheelie in front of some sexy girls! 

[G-MONEY]

Hey redfoxcr would you check something for me. On the left side of the cylinder there is a round plug that you can remove with a 17mm socket. Remove it and start the engine,  rev the engine an see if the end off the shaft moves. There is line cut in it. On the cylinder there is the letter H and the letter L casted next to the hole you removed the plug from. At idle the line should point at  the L and when you rev it up it should move to the H.Check this out and let us know.

[ford832]

About the vent hose. I recently heard that helps. 
So, how can i see if the float level is OK? One guy suggested to put the opened carb onto a glass jar and make the gas flow down. When the float comes up, the valve closes and the fuel level remains constant. Is there any easier solution? Without a jar and gas spilling everywhere?

Don't plug your vent hoses.As for the float,take the bowl off and tilt the carb so the float "just" touches your needle-not depressing the little plunger.This should be your measurement spot.If you don't have a spec,level from the flat of the bowl seat is a good start.

[RedFoxCR]

Thanks a lot, guys! That must help. To G-MONEY: yeah, buddy, i know what are you sayin', about the shaft moving the exhaust valve... So, when i unscrew the cap, i'll see the end of that shaft, won't i? and it should rotate from one mark to another. Thanks a lot. I've spent ages hesitating if my exhaust valve works or not! Now i'll find it out.
But i still think the mixture is LEAN.