alright, im working on my friends 05 big bear 400, he sunk it a while bike and im trying to fix it, i change the oil 4 times and made sure there was no more water in the motor, i cleaned out the carb and the jets which had a **** load of sand in it, started it and it smoked like hell which i expected, i put it in gear and it just killed on the spot, i tryed it again and it did the same thing, im not sure if there's somthing else wrong with the carb that the sand could've caused or if the piston ring is blown or if there's a bent valve, it seems like it has compression but i havn't don a compression test on it yet, giv me some tips of what could be going on...

 

if it was a street bike id say put the kick stand up . but maybe clutch is sticking enough to kill it

 

i would do a compression test, sand will will give the rings and cylinder a beating, and look at the clutch and clean it, it might not be dissengageing. did it jump forward when you put in gear?