How do I higher my 2004 kx 85 - 2004 kawasaki KX 125

85 octane or higher

If you have to ask, really, you shouldn't

Check gaskets, seats and hoses

If gear box making clunk sound, you have to tell this to Authorized Service Professional.

they should if you make them mate

Well there are more questions to be asked. Is your bike all stock? What ratio of gas are you running? And have you made sure your carb is clean

Sounds like a bent shift fork.

You want heat up ????? Not clear if you want heat higher on the engine or cabin. Engine, you should probably leave it alone. The manufacturer warns that running higher temp thermostat may cause overheating damage to engine. If you want heat up in cabin, by nature and design there is a limit to how much heat is put out. Colder days it simply may not provide a sultry 85 degrees, if that is what you mean when you say "you want the heat to go up". Maybe try wearing a jacket.

hi buddy for engine oil use silkolene comp 2 plus sx or silkolene comp 2 premix also for gear oil use silkolene light gear oil and for coolant use silkolene pro cool also mix the oil with a mixture bottle on ebay etc use 40:1 ratio

Start with setting the air and throttle screws. Turn each one inward until it GENTLY seats. Back each one out one and one half turns. Clean the air filter and starter plunger. The plunger may need to be rebuilt or replaced. Check the pilot and main jet sizes. There will be a number stamped on the side of the jets. The pilot jet should be #45, the main jet should be #140.