i have a 05 klx 110 with bbr 143 bore kit, BBR 4th geat shift drum w/ shift star, Magura hydro clutch, bbr forged output shaft ... works fine. Just did the exact thing to my nefews 06, same parts and everything but when shifting it goes into neutral on both up shifting and down shifting! The 110 was pretty much band new before the overhaul and was shifting fine. I cant figure out the problem! the motor was assembled correctly and all bolts in the entire motor are torqed to specification. PLEASE HELP

obviously it wasnt assembled correctly or it wouldnt be doing that. Is it going "into neutral" or just not grabbing a gear? Check the shift arm behind the shift star and make sure all the pins are on the shift star.