Stupid Question I Know But............

[Thumper]

It's a stupid question but I just need some reassurance. When you turn the pilot screw (fuel mixture) clockwise does that make the mixture leaner and therefore if you turn the screw counter clockwise does that make it richer????

[Ken Talbot]

That is correct - turning the screw "in" will lean out the idle mixture, turning it "out" will richen it up.

[Geezer]

Not a stupid question at all. The rule is if the screw is downstream of the slide, in to lean. However if the screw is upstream, of the slide, turn it in to richen the mixture.

The carbs on the XS11s and others that have the screw downstream, the screw meters fuel. Open it up and it let’s in more gas.

On bike with the screw upstream, the screw meters air into the idle circuits. Turning it in clamps down on the air supply causing a richer mixture.


Geezer

[Thumper]

Thanks lads, I was beginning to go a little insane with my plug colors/poor running. I must be getting a false reading because of all the revving I having to do to get her moving at junctions, traffic lights etc. Off to Halfords at 12.30 to see if I can buy a colortune.