Throttle valve height / AP Timing Adjustment

Set your idle first, then adjust the timing screw. I find that the screw should be adjusted so there is a very tiny amount of travel in the black piece before it touches against the pump rod. Shine a flashlight at the top of the rod to see this tiny gap. If there is a large gap you can gently push the black piece down and actually feel when it touches against the pump rod.
Note that any change to the idle stop srew will reposition the mechanism and change when the pump rod moves. For the throttle slide height I remember having mine at about 3.5mm (bottom of carb bore to bottom of slide, use a drill bit as a gauge). That is just where I set it after installing the jet kit; I've barely changed it since. I do need to reduce my pilot jet so this distance will likely change.

my gap is more like .5-1mm gokia! infact i can't get a drill bit in there i think!

carb is down at present so i'll report back if you can wait a few days.

you want the pump to start as you touch the throttle -in other words ASAP.

it should stop as soon as possible and on the mk1 carb this was found to be .6mm which someone reckoned equated to 1 second (o yeh! and how good was he on the stop watch!) but it wants to be as short as the pump can handle without actually stopping from functioning.

neil is right about the little gap.

regards

Taffy

gokai

not sure where you are coming from because nobody has ever had anything but the 0.5mm i thought from the factories? whenever i've read any specs, the slide cutaway height has been 0.5mm on every single bike.

because you're both quoting such high numbers i must have got the wrong end of the stick altogether and i'll shurrup now!

regards

Taffy

Pardon my possible ignorance but I thought only two strokes had an actual silde cutaway. Maybe the FCR slide has a tiny chamfer on the inlet side. I'll have to pay attention the next time I look at it. The distance I meant is looking into the bore from the engine side and seeing the opening from the slide to bore. This distance being a result of the throttle screw (idle) setting.

The manual lists 4125D as the number for my FCR.

That picture shows it exactly. Basically you are using a known dimension (rod diameter) for your initial setting. Always get the idle correct before checking the pump timing.