I received a few emails asking me to clarify how these needles differ in feel so below is a fuller description. These settings are for sea level, 70 degrees, tested in a 06 DE300 and a 06 DE250. The bikes are American DE models with the lighter ignitions, stock GG pipes and FMF Turbine Core II mufflers. The motors are stock with stock base gasket height and RBD head mods. The stock #7 slide was used for all needles. Pump gas 91 octane, oil mixed at 40:1
45 pilot LTR-0#3 175 main:
Slightly lean at 1/8 to 1/4 throttle giving the bike a hit at off idle and then the richer end taper makes the bike feel weak from mid to top in the 300. The motor will idle cleaner with a 42 pilot but this makes the 1/8 to 1/4 throttle hit even harder. Works better in the 250 than the 300 as the 250 is still able to spin up with the richer end taper and the hit at off idle isn't as strong. If LTR would radius the transition from the straight section to the taper to soften the hit, it would be a good needle for the 250.
42 pilot, CCK#3 178 main:
Very smooth, easy to control, torqy power from bottom to top with no hit anywhere. Works in both 250 and 300. Good choice for those that prefer throttle control for picking your way through rock gardens or tough survival rides. This needle also works well for novice racers who get tired before the end of a race and struggle with throttle control.
42 pilot N3EG#3 175 main:
This needle is for racers and gives the 300 the most power with a strong mid to top pull. My 300 has the dual ignition and this needle in the MX mode makes for a lot of mid to top power. For slower, tight riding, I ride with the ignition in the rain mode and this takes the edge off the power and makes it more controlable. In cold weather you will need to use the 1/2 clip richer N3CG#4 with a 178 main or you will get a little rattle from mid to top. These needles do not work in the 250 as these needles are too lean on the end taper and make the 250 too revvy. I race A class and this was my favorite for my type of riding.
45 pilot JD red#3 175 main:
This needle in the 300 feels like the N3EG needle on the bottom but does not pull as strong from mid to top in the 300. You get a clean bottom pull with a more torqy, mellow mid to top pull. A little too mellow for my taste. In the 250, it gives the bike a torqy mid to top and doesn't hurt acceleration. This would be my first choice in the 250 although at $80.00 for the kit, it is way over priced. For about $7.00 you can make your own crude JD red copy from a DDN needle. This needle has the same straight section diameter and a 45 degree taper simular to the JD's end taper. Chuck it up in a Dremel and sand the transition from the straight diameter to the taper at 34 degrees. This will make it a multi taper with the first taper at 34 degrees and the second taper at 45 degrees. The JD red is slightly lean in cooler weather at off idle so If your going to make your own, A DDL may be a better choice with it's smaller straight diameter. DDK has the same diameter as the JD blue.
Hope this helps, Dave
