Just been dealing with that problem myself. I had put a 250r carb on it as a temp fix. I got a 350x from hondaatcvabeach on this site and tried that carb. It didn't work but checked the slide on both and my old one was scuffed bad and kept sticking at 1/8th to 1/4 throttle. I swapped the slide and have a regular 350x carb on my bike again. Try to see if the slide is scuffed and if it is, I don't know if you can get a replacement from Kehihn or not, or Honda. Worth checking though.
06 Yamaha Bruin 4x4
04 TRX Rancher 400 AT 4x4 GScape
86 ATC 250es Big Red
84 ATC 200s (31 yrs running strong)
13 F150 4x4 SuperCrew 5.0
00 Excursion V-10 lifted with 35s
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Gone
07 CanAm Outlander 650, 05 TRX 450R, 85 ATC 250r, 01 Kawasaki KLF Bayou 220 , 02 400EX, 85 ATC 350x, 84 ATC 200x, 85 ATC 350x , 98 KLF Bayou, 86 ATC 250r