Well boys, I do like to be different so when I saw Taffy going off in his own direction I grabbed his coat-tails. Call me a plagiarist. I dont care. It WORKS. Cust #1 is WELL satisfied. Hop on board people and when you do, don't dick around....go the whole hog in one jump as this is a working interactive system which likely wont work in 'sections': I tried a different needle with similar jets and although it was workable, wasnt great all round. This setup IS. 99 WR400 YZ timed De-Octopussed 38 PJ 55 PAJ 155 MJ (Taffy now moved to 150) 165 MAJ (Taffy now moved to 160) EMM Clip 4 Fuel Screw 1.5 turns NO APJ Stock START JET First gear starts - Great 1'st-2'nd gear wheelies - just snap the throttle 3-4-5 'th - carefull, wheelspin city. Uphill 3-4'th gear hauls - revs. like crazy Mid range - RAPED APE! Top Speed - don't know, my speedo is a little cranky, but FAST as hell In a fall - will NOT stall Decel - no popping but no sign of richness that I can tell. Excellent fuel economy Just Do It PS : A small word of caution....my WR still has the stock EU exhaust as does Taffy's, although he has a FMF PB header. I'm sure JD and/or Taffy could provide some insight into adapting the above for a freer flowing exhaust.