Oil checking yahaha dt 125 r 1999 how do i check the engine oil?

You can purchase a dye to add to oil, it will show leak location when you shine a light on it.
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Using UV Dye to help find oil leak
Tracer Products Dye Lite TP3090 0601 Gasoline Engine Oil Dye Reilly Auto...
http://www.garagejournal.com/forum/showthread.php?t=89730

engine oil dye

10W/30 or 10W/40 is what I use in mine, as per the manual.

To change your oil you will need 4 quarts of oil, a filter, and a new aluminum drain plug washer. You can reuse the old drain plug washer if it has not been squished out of shape. Your motorcycle comes from Honda usually with 10w-40 mineral base motorcycle oil. You can use any oil that is JASO MA certified motorcycle oil. 10w-40 for cold climate. 20w-50 for warm climate/touring. Car oils use different additives and may cause scoring in certain types of cam bearings. Do not use any oil that says " Energy Conserving " on the label . It will shorten the life of your wet clutch and transmission gears. If you choose Synthetic oils, they will help your bike run cooler and shift easier. Pour in four quarts of oil to reach the high mark on the dip stick or inspection window. Make sure the motorcycle is upright or on the center stand when checking the level . You will probably need between 3.1 and 3.4 quarts to hit the high mark. Run the motor for a minute or two to fill the up the oil filter compartment with oil. Now recheck the oil level and top up as needed. If you want to try an inexpensive full synthetic oil that is JASO MA rated 15w-40 Shell Rotella T Synthetic fits the bill at about $22 per gallon. All brands/manufacturers make a motorcycle oil. Some are very hard to find. Just make sure that the oil you pick has the JASO MA Japanese engine Rating to protect your motorcycle engine.

DT yamaha,s are a 2 stroke, the oil is pumped into the engine and burnt with the fuel, at aproximately 30-1 ie: every 30 litres of fuel will burn 1 litre of oil, this is how the engine gets its lubrication , without it the engine will be destroyed, they also have gearbox oil which only lubes the gears and clutch

Dont be confused between the engine oil and the gearbox oil.

The oil in the tank gets burnt with the petrol, and needs replacing as it gets used,, it is two stroke engine oil.

The gearbox oil is drained through a plug underneath the engine, it lubricates the clutch and gears only, it is 20w40 motorcycle oil, it can be the same as a fourstoke motor, as it is for the geaxbox.

Do not be tempted to use car oils as the clutch may start slipping.
Go to a bike shop and tell them the bike model and they should sell you 2 bottles of oil, the lables will also explain.

hi,most two strokes run a gear oil in the gearbox,unless specified by the manufacturer dont use engine oil as it is not heavy enough,i use a 75w gear oil in my nsr 250 and it works fine..cheers

This being a diesel, lack of compression is your worst enemy. These symptoms sound like a blown head gasket. Check your coolant for signs of oil, and check your oil for signs of coolant. (oil will be milky looking) Also indicative of a head gasket problem is an oil or coolant leak from the engine as well. If you see no evidence of the above, have a compression test done, and it should show up.

try decarbonize piston and rings, for two stroke like DT 125 check the 2t oil pump

10w40 is what you want for the gear box. Yamalube two stroke engine oil is what you want for the small oil resevoir side cover

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This is normal. The air filter is re usable on a lot of two stroke engines and you wash the filter and oil it lightly to help catch dust.