KOUBA FUEL SCREW.If you have ever tried to adjust the air/fuel mixture screw while the engine is running, one of these is a must!

If you have ever tried to adjust the air/fuel mixture screw while the engine is running, one of these is a must! KTM Newer FS 250/400/450/520/525 Yamaha YZF/WR 250/400/426/450 Honda CRF250/450 Suzuki DRZ400E/KLX400R Husky 2005 4-strokes Note: The Kouba fuel screws have a maximum usable range of approx. 2.5 turns out from seated, any farther will take the tension off the friction spring and allow the fuel screw to vibrate out. :-( If your bike runs the best at near 3 turns out, a larger pilot is most likely required.