Mixture proplem I have a 1992 yamaha dt 125 r wont start sounds like a mixture proplem? when i drained oil it was funny brown color is this right? Have checked spark and its fine even bought new plug to be sure but just wont start any ideas?

The brown oil is water mixed into the oil. If I recall correctly the DT bikes were air cooled. The water would be condensation in the gearbox. Just drain the oil and ride more often. If the bike is water cooled the two seals on the water pump shaft are bad. This is not a major repair. The bike probably needs new crank seals. Go ahead and clean the carb as water and trash may have accumulated restricting the fuel flow to the motor. Install an in-line fuel filter.

Use TWO STROKE ENGINE OIL in the pump. If not using an automatic oil pump, then mix the gas and oil 32 to 1. That equals 4 ounces of TWO STROKE ENGINE OIL to one gallon of gas. NEVER use motor oil in the gas. Only two stroke engine oil. Use 10w40 motor oil in the gear box. Don't use any synthetic oils, oil marked "EC", or oil with "special" additives. Stick with the major brands; Pennzoil, Quaker State, Mobil or Shell.

ALWAYS have a fire extinguisher on hand when working on carburetors.
Remove the water trap bowl at the bottom of the petcock, (gas valve). Is there any water or trash in the bowl? Drain a cup of gas from the tank. Is there any water or trash in the cup? Dump it, clean it and re-mount it, ( not all bikes have a water trap bowl ).

Drain the carburetor. There should be a screw on the lower side or bottom of the carb float bowl. Remove the screw then replace it after the fuel drains. Turn the gas back on and wait a minute for the carb to fill with gas. Try to start the engine. If the bike doesn't start and run properly then shut off the gas and remove the carburetor from the engine.

Remove the float bowl and clean the entire carb with a spray carb cleaner from the auto parts store. Wear protective goggles to avoid getting spray in your eyes. Spray into all the little airways and fittings in the carb. Remove the idle screw and the air screw on the outside throat of the carb and spray into the screw holes as well.
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Be sure to put these two screws back in the same hole they came out of. IMPORTANT > do not tighten these two adjusters down. Only screw these in until they LIGHTLY seat. Now turn each adjuster one and one half turns outward. Put the rest of the carb back together, clean the air filter and install the carb. Let the float bowl fill then start the engine.

If the tank is rusting, you need to seal it up. Google “ kreem fuel tank liner “ or go to www.http://www.4secondsflat.com/Fuel_Tank_Sealer.html