WHY LINHAI REBEL 400 OVERHEAT

see link

https://www.manualslib.com/products/Linhai-Atv-300-3776932.html

https://www.manualslib.com/download/1061798/Linhai-Atv-260.html

Let it dry a few days and try again.

no gears in a CV transmission
it is a belt between to variable pulleys
as the one pulley gets smaller ( flanges come together ) the belt pushes the other pulley flanges further apart
if you are slashing gears in is in another part of the transmission /transfer case

Sounds like a air leak maybe.,.or a sticky or kinked throttle cable check that lube or replace .,.clean your air filter, and intake ,and carb / fuel injection parts., tune it up?

looks like the hard way
cant find its repair manual online

have to take off some casings

take battery out
drain all fluids
try flipping it on its side or upside down

its drive train clutch

To see if the charging system is getting to the battery, buy a MULTIMETER:

http://www.harborfreight.com/7-function-multimeter-98025.html

Make sure the battery is fully charged, then connect the multimeter to the battery (black lead to NEGATIVE, red lead to POSITIVE).

Make sure meter is set to DC VOLT, start bike, and take a reading.

On a 12 volt system, you should be getting somewhere around 13-14 volts, with a slight increase when you rev the engine.

Battery or battery cable connections. After you get it running make sure the charging system is working. Maybe riding it ran the battery dead from it not charging properly.

Under the flooring on the right side