Low Fuel Economy - Running rich, not sure why

[JohnC]

That plug is pretty black. Can you adjust the (slide) needle down at all?

[5th_bike]

Originally Posted by JohnC

That plug is pretty black. Can you adjust the (slide) needle down at all?

I agree, way too black. The bike should get about 200 miles out of a tank, until reserve. The carb's float needle/seat combo is still leaky.

[JohnC]

One thing you can do is to connect a piece of clear plastic tubing to the float bowl drain. Fold it around until the open end points up, hold it up against the side of the bowl and open the drain valve. Stand the bike up, turn the petcock to "prime" and observe the fuel level in the bowl, equal to the level in the tube. IIRC, it should be about where the seam is for the bowl gasket, mid way for and aft along the seam. More importantly, it should not continue to rise to the point where fuel overflows.

If you are careful, you can even check the level this way while the engine is running.

[Water Warrior 2]

Originally Posted by JohnC

One thing you can do is to connect a piece of clear plastic tubing to the float bowl drain. Fold it around until the open end points up, hold it up against the side of the bowl and open the drain valve. Stand the bike up, turn the petcock to "prime" and observe the fuel level in the bowl, equal to the level in the tube. IIRC, it should be about where the seam is for the bowl gasket, mid way for and aft along the seam. More importantly, it should not continue to rise to the point where fuel overflows.

If you are careful, you can even check the level this way while the engine is running.

WOW, is that a neat way to check the float and fuel level.

[JohnC]

Here's a photo. It's not a Mikuni carb, but you get the idea...

[attachment=0:3gzcwcor]P6060249.JPG[/attachment:3gzcwcor]

[Water Warrior 2]

Originally Posted by JohnC

Here's a photo. It's not a Mikuni carb, but you get the idea...

[attachment=0:1jgggg56]P6060249.JPG[/attachment:1jgggg56]

:2tup: :2tup:

[jonathan180iq]

Follow this link to see John's idea on a GS500, which is the same carb as the 250, just times 2.

http://www.gstwin.com/float_height_check.htm

[Ultimx]

Not to thread jack but I have the same problem. I just bought this bike and the po said he adjusted the carb. I need to open it up but was wondering does anyone have the factory manual? The forums one in the sticky doesn't work. I would like to see the parts in the manual before I go opening it up. I am hearing little backfires in the exhaust but my bike is completely stock. Thanks guys.

[jonathan180iq]

Ultimx, we have a temporary fix on the service manuals. Try them now.

http://www.gz250bike.com/forum/showthread.php?t=28