I have the same sled and had reverse issues as well several years ago. The issue was the magnet inside the chain case that the reverse sensor picks up on had too much metal debris on it so the sensor could not "see" it. I recked my reverse actuator trying to figure it out. Look in the Viper issues log area and see the write-up I did for how to use a Saturn passenger door regulator that costs around $30 rather than $240 that Yamaha and CAT want for a factory actuator. You will be able to see how to get your chain case apart to clean the magnet in that section also. When you are in you chain case, weld the tensioner bolt, replace the plastic shift forks feet (them wearing out might also be your problem) with brass feet and check your top gear bushing for excessive wear. When I fill my chain case I use 75-140 Mobil synthetic ATF and pour the whole bottle in. Since using the ATF I have not had a single issue with my chain case. Yamaha and CAT dont use enough fluid to keep the chain case happy.