2017 Trx420FA6 won't shift pass third gear
 

With motor running, Bike will display N, 1, 2, 3 then --. It will not shift up or down at this point. With motor off, key on, it will shift up to 3rd, then --, but you can shift back down to N. I have taken the shift motor apart and cleaned, changed angle sensor, cleaned out just about every connector. Bike does not shift pass 3rd when manually shifting with a ratchet on the shift shaft. I am at a loss. It was running fine, then I go to get back on it a week later and this. Wish I would have bought a foot shift.

To hell with it!
 

Don't bother replying, I have spent the entire weekend messing with this thing. I am done diagnosing, back to Honda it goes.

Any update? My bike is doing the exact same thing. I cant figure it out and ive tried everything Please lmk!!!

Don't know how I missed this in 2018. FA6 won't change gear properly unless the computer thinks you are going at roughly the right speed when in ESP. No good trying to change past second when stood still, it won't do it. If it won't change past third when on the move, there are lots of things it can be but first thing, is it throwing a fault code on the speedo display? It is in Morse so you need to count the long and short flashes of the gear indicator. Does the speedo work properly? If the speedo sender doesn't tell the computer what speed you are doing, it thinks you are stopped. If it doesn't throw a code, it may have a selector problem. Most common is the pin, that a spring shoves against, broken. If it was a manual, you press the pedal and this spring pushes the pedal back to the midpoint when you take your foot off. ES and new autos still use it and it spins the shift motor back to where it started. Bent selector forks and worn gear "dogs" are not unknown. Had an early one recently with wear on the star wheel mechanism, tiny amount, may not have caused the problem, as I took the box apart to fix worn 4th gear dogs, but it used to do weird things like change 2 lower gears at once, before the rebuild.