[sho305]

The low speed gears might be the best option. Otherwise I would tell you to service the primary clutch on the engine, ensure its working properly. Then get a HD kevlar belt from CPP, get a cut secondary sheave someone has them new CPP or cartpartsplus maybe others but be wary of the cheap china ones that are too thin. Also make sure the engine is not moving under torque, check the tension cable if it has one it holds the engine away from the trans, tighten it up if it has one. You can tighten them until the belt is starting to drag. Also get a umax spring for the secondary that will keep rpm up. The governor will limit speed for you but not sure what the point of that is. The low speed gears will do a lot for that use but they are not given away or the labor to install them. i would say the cut sheave would help you the most it gives a lower gear, the belt works great and will also help lower the low gear a little, neither of those will affect much other than initial take off and power at the lowest 'gear'. The umax spring will hold rpm higher until you get to high speeds when the rpm is higher anyway, and its a yamaha part. It you preload it more it will hold rpm quite high all the time. If you put the low gears in you may not have to do that stuff other than making sure the clutches work right and I'd recommend a new belt or the HD belt would be nicer.