I HAVE A YAMAHA WARRIOR RUNS STRONG UNTILL IT GETS WARM THEN THE CLUTCH STARTS SLIPPING. NEVER SLIPS WHEN ITS COLD.

 

it's a wet clutch isint it first thing is to try adjustin the clutch it's i think it's some thing like 5 mm free play at the handle lever but you should check for sure and theres usualy an adjustment skrew at the clutch that may need adjusted too if that doesent work your clutch is probably going to need replaced what i believe is happening is the clutch doesent slip when cold because of the higher viscosity of the oil and when it heats up it lowers the viscosity and no longer assists the allready worn clutch