Float height

[rerfurt]

Yet another float height question.

When buying my CR 250 03' used, I noticed the bike kept drippin all over the place and was running real rich. I inspected the float height and found it to be 6-8mm - not good.
I installed a new needle valve and adjusted the float to 15mm(according to manual) meassured from the carb body (where the bowl seals against the body) to the bottom of the float - again meassured when the needle valve is seated and the little piston in the end is just starting to compress.
I checked for leakage by blowing into the gas line while positioning the floats at 15mm - no air coming through - at 16mm I hear it wissle.

The bike now doesn't drip when held completely upright, but the slightest leaning makes the overflow pipe drip immidiately, also I am running slightly rich, especially at low rpms - it appears to me that float height is still not 100% correct ?

Did i miss something here ? I double checked everything 3 times, and I downloaded specs from mikuni that also stated 15 mm float height.

The carb is a TMX flatslide btw.

 

[rerfurt]

Anyone ?

 

[Morvo]

Did you check the float for holes (pin hole pricks), and also whether it moves freely without catching? The bike might be running rich because of the size jets in the carb, try leaning it out a bit or maybe change your needle position to a leaner notch.

 

[rerfurt]

Thanks for your reply,

The float appears to be ok (plastic/foam type - I find it hard to check). I am in the process of correcting the jetting, I just wasn't sure the float height was correct, when the bike keeps drippin gas, when leaned slightly.

 

[biglou]

How does the float needle seat look? Soft, no cracks, clean? Not even a speck of debris? A Q-tip works well for cleaning the needle seat.

Is the float pretty much level when adjusted? I usually adjust so the seam in the floats is parallel with the carb body where the bowl seats, or if no seams on the floats, I adjust so the arms molded into the floats is parallel with the carb deck where the bowl mounts. Does yours look to be greatly off from prallel when adjusted to 16mm?

 

[rerfurt]

Thanks for your input, I took the carb apart to inspect it again. Needle seat was in perfect condition, and the float seam is pretty much level with the carb body. I did find a little bit of water trapped in the pilot circuit, and I found the previous owner installed a pretty rich main jet (450 as opposed to 420 stock) - that explains the richness anyway.

Maybe the overflow circuit is simply a little off on this particular carb, since I can find nothing wrong with the float level.

 

[rerfurt]

Okay, I finally solved this one.

It so happened that the O-ring sealing the inlet needle seat to the carb body had hardned, thus letting fuel bypass the inlet needle. The oring appeared ok upon first inspection, but looking closer it had a glaced look on the mating faces and felt all hard compared to a new one.

Again thank you for your input on this one.