4th gear went out on the bike. Looks like the repair will cost about 1000 bucks. Any suggestions or advice for getting this fixed? Any gotcha’s in repairing myself? Any special tools needed if I do myself. I am a bit concerned that other issues my be looming. I hate to tear down and fix 4th gear just to find that 3rd goes next month or top end needs replacing. Any experiences you can share around this would be appreciated.. What about changing to a WR 5 speed. Since the thing is opened up this may be a good time. I never liked the 4 speed anyway. Anyone done this? What’s’ the cost? Anything special needed..