Too lean or an airleak in the exhaust.

 

So I was screwing with it for an while, did the stall test with 1k rpms to see when the bike would stall, stalled at 1 turn out for lean and 4.5 turns out for rich. Set the screw to about 2.75 turns out and a lot less popping on decel, maybe only pops once or twice on decel from high rpms down to 4k, seems to be running a lot better, hope my gas mileage isn't way off compared to before. Does anyone notice any mileage difference switching from stock mixture screw to the kouba FS-2?

 

Start at 2 turns out from gently seated position. Start bike and bring to operating temp. Slowly turn the screw in until you hear the idle begin to drop and back out 1/8th turn. Now turn the screw out until you hear the idle begin to drop and turn in 1/8th.

Somewhere between those 2 screw positions is the perfect mixture adjustment for your bike at your altitude. I prefer to turn the screw in (lean the mixture) until the idle drops and back out 1/8-1/4 turns.

Once you get a feel for this you can easily tune your carb based upon your environment [altitude].

 

anyone have a picture of the screw on the carb/on the bike?...i want to see how much easier it would be vs. just using the little phillip head (which i think is pretty easy)

 

IMO, for as often as you need to adjust your mixture screw it's a waste of money.

 

If you always ride at the same elev or you have a CV carb, adjustment should be rare.
If you have a slide carb and ride at different elevations, get the kouba.

 

Small price for the convenience it provides, easily adjusted while your riding... Even when the engines hot

 

The paper that comes with the screw says to adjust the idle down to right before it stalls which was about 1k rpms for me, it stalled at 1 turn out for lean and 4.5 turns out for rich so I figured 2.75 turns out was right in the middle. But the paper also says not to have the screw turned out more than 2.5 turns because it may vibrate out. I have been running it with the screw about 2.25-2.5 turns out and seems to be running great, hardly any popping, decent gas mileage, and seems like it has a little more get up now.

 

Mines been 2 3/4 turns out for 3 years now and has never moved in or out.

 

I bough one at my local Harley shop, not a Kouba but they had several in stock and evidently some Harleys use the same carbs or similar to the Klx's