Well, remove the 4 screws that hold on the hi/lo cover and have a look inside. This sub-tranny is isolated from the rest of the engine and there’s only a couple gears so it’s easy to get to and see what’s going on. Your internal lever could be bent or broke, it could be missing the high gear... who knows.
My guess is that the lever is not engaging the the peg on the shift fork, or shift fork is not properly engaging the flange on the low speed gear to slide it over into HI.
Here’s the schematic:
Last edited by Black_Widow; 12-03-2017 at 12:13 PM.
1983 ATC 110
1983 ATC 110
1984 ATC 125m
2003 CRF 450R
2015 Suzuki M109R