Just a little "FYI" here.
Bought a Factory Pro jet kit from the local dealer (my bad!). While the jets included were fine (37.5 pilot;175 largest main), the slide needle was useless. It had 5 grooves for the c-clip. The motor would not run w/the clip in any of them. Started w/clip in 4th groove. Motor would start right up & idled great. As soon as I moved the throttle, the motor would begin coughing thru the carb, & if I tried to gas it up, it would pop thru the pipes. When I released the throttle, it would return to idle.
Pulled the carb back off 4 times & moved the clip to each groove with the same results each time. I was ready to take a Sledge-o-matic to the carb.
Pulled it off one more time & put the stock slide needle back in. PRESTO!! Now the motor starts right up, idles great, & hauls butt!

Did you buy the kit because you changed your
Air kit? Normally the stock needle won`t work well
with an after market kit because it doesn't let in
enough gas.

you have a 1600 right, those pilot and main seem way to rich, that is why you are not getting results.

Mikuni or DJ jets? this is mikuni numbers listed. stolen from Musky posts but got to listen to the pros they have been through all the trial and error already.

"4th clip, washer under" I'm assuming that's under the clip. Do you have the spacer between the clip and the washer

When you did the WOT did you have the clip in the 5th groove from the blunt end

I would start with the 167.5 when you do the WOT. The WOT only tells you if you have a lean main, not a rich one. If you start with the leanest jet and it tells you you're lean you can go up. But if it says you're ok then you won't be running any richer than you need to be. If you start with a richer jet it won't tell you you're richer than you need to be.

These babies like it rich but won't run well if it is too rich same goes for when its too lean.

Hope this helps,
Paul

Which jet kit? They offer 3. Did you try talking to their tech support? I called them one time to find out something, a least the guy I talked to sounded quite knowledgeable.

http://www.factorypro.com/

M-F, 9am - 6pm, Pacific time, -7 or -8 GMT

800 869-0497
USA and Canada

415 491-5920

What do you have for main and pilot? If you put the 37.5 pilot in, that might be part of it...not sure though. As I remember, the needle doesn't come into play until past ¼ throttle. Good luck. Oh, how many turns is your PMS out???

I'm running an Ultima breather,Speedstar 2 1/4" straights,& Dyna-jet rev master 5000 rpm limiter.
Ended up w/a 37.5 pilot,175 main,PMS 2 3/4 turns out.
Motor starts right up, idles real smooth,is very responsive,& will haul the freight! It's runnin' better than ever!