confused with my yz

[camestr]

I bought a 2003 yz 125 used about 3 months ago and it was fresh off top end rb
. recently tho i noticed that it seemed to be lacking power on powerband and it feels as tho the jettingis wack. so i cleaned my airfilter, repacked my silencer, new plug and tryed about every different jetting settings known to man, with no luck as i am steel feelin the flat spot on my excelleratiion about 3/4 throttle. what i think is the float setting is way off and it is flooding out at high rpm. now i have never set a float level before and i was wondering if anyone could help me out? o and im 95% percent sure its not a piston but if it is i have 4 spares. why tho would my float setting just go out of wack so randomly and would this account for my overflow dripping gas slowly overnight if i leve the petcock position "on"?

[spartanbiker_117]

Not too sure about your last questions but here is a very good guide to setting your float level

[ossagp1]

yes on your last question. they don't just suddenly go "wack". setting that is a "MAITENANCE" item that many don't do. James Stewart's gets adjusted or at least checked between each event. Yours like most others probably last got it when it was made.

When you have it apart and look at the link you will see why it can happen. It just has to get extreme like yours is before most riders notice.

It may not solve all your problems, a 125 with 10-15 hours on it won't run like a fresh one. Especially if the last top end was just a simple ring or ring and piston job on a 4 year old bore. They can run really nice, but won't be like new. It is what most of us ride on actually.

[camestr]

the bike is pretty much fresh of top and bottom rb and it just seems to have a flat spot at high rpm ive tryed soo many jetting setups but have yet to set my float height. guess im gunna have to puzzle it out and fix it ha

[ossagp1]

It is really pretty simple and once you do it you will feel it was even simpler. I have a pretty similar carburetor to yours. If you take the post by Faded and look at the pictures and read it through you will see what you are shooting for.

In the case of that mikuni take the bowl off and turn it upside down. Bend the tab that the needle rides on to where it just makes contact with the needle at the point where the lines on the floats are parallel to the carburetor body. You have to see it all for any of this to make sense.

You can't jet a bike very well until the float is correct. A waste of time to try, really.