Ok, here's what I got:
102mm 12:1, S1 Hotcam, ported head, 1mm oversized valves, Sparks X-6 ss exhaust, & Keihin 35mm FCRs courtesy of Sparks racing.

It came supplied with 145-148 main jets(elev approx 800-1000', 60 deg, dry weather), OCEMR needles, clip=5 each, 200 main air jets, slow air jet approx 1.5 turns out each, pilots=52 each, fuel screws =1.75 turns left, 2 turns right. It took longer than normal to drop down to ilde rpm after receiving throttle so 2.25 turns left/right fuel screw fixed that. Also, the top end responded better with 145-150 main jets.

So it runs like a raped ape except for one major problem, it bogs big time off idle/low rpm with rapid throttle requests. I know you can't instantly nail the throttle on any carb & expect full cooperation but my stockers never ever bogged like this! They might have hesitated a milli sec or two but this is a long bog before it recovers!!! The reason I got the FCRs was there supposed flawless throttle response. I can see flipping over after getting back into the throttle on a long/steep/technical hill climb. I have been there & done that when the stockers were way too rich on top.

There are many articles on this problem with the FCRs including many stock OEM dirt bikes. Apparently, most FCRs come with an adjustable timing screw, duration screw, & leak jet. None of which is available on these FCRs, WTF? I did try the timing slot to the right with no luck, it reduced the squirt duration a little. I measured the squirt to be around 1.4 secs long before the change & it was just under 1 sec after.

I tried widening & closing the split tab against the plastic pump linkage with no luck either. This affected when the squirt started. I even had it starting the squirt so early that it was hitting the slide thus throwing away gas & this actually seemed to help. That is why I am thinking about drilling a hole in the leak jet plug to bleed some of the fuel back into the float bowl to see if a lower volume of squirt is the answer. I really hate do any drilling on these already.

I even tried running without the acc pump but then it had a lean bog, at least it wouldn't stall this way though. Any help/advice would be greatly appreciated. Thanks!!!!

 

I am trying suggestions from Sparks. The clips should have been on either pos 3 or 4 from the factory, they were on 5. Also, I may need to try smaller pilot jets with more turns out on the fuel screws to compensate. I didn't think it mattered as long as the end result mixture was correct but apparently the pilot air jets feed two circuits & thus have a two stage effect.

I see hundreds of articles & posts about people having a bog off idle problem with the FCR carbs utilizing an acc pump including bikes & quads right off the showroom floor. So, there has to be at least one person on this forum using the FCRs on their Raptor who either has or had this problem or who lives with it & is ashamed to admit it? C'mon guys, throw me a bone ........