Old Yam DT125 question - 2 stroke?

I just purchased an old 1979 Yamaha enduro from a neighbor for $100. It had been sitting in a garage for 10 year, but the thing looks and runs great. The problem is that I don't know anything about this bike. I believe it's a DT 125F which is a 2-stroke enduro model. The only other 2-stroke I've ever owned was a YZ80. I always thought you had to mix the oil and gas on 2-stroke, but this bike as an oil reservoir and the neighbor said you only needed to add straight gas in the tank. Can this be true? Does anyone know anthing about the DT 125's? I'm not much of a mechanic! Any advice would be appreciated.

I dont know anything about the bike you have but its not uncommon to have an oil injector on a 2 stroke. so I would say yes, put gas in the tank and pre-mix in the oil res.

I run Bel-Ray HR1 pre-mix oil.

[ June 19, 2002: Message edited by: StreetMoto ]


I had a '74 DT 125 when I was a kid. It was two stroke with an oil injector. I'm sure that yours is the same.

Use straight gas in the tank - the 2/stroke oil goes in the oil tank which if I remember correctly was on the left side under the seat.

Good luck.

Yes it DOES have the injector pump. Make sure you use the RIGHT oil, NOT 2 stroke pre mix (Bel Ray MC-1, etc).

The injector pump should have a setting on it to ensure it is injecting the right amount of oil, usually two marks have to line up on it (somewhere).

Get yourself a Haynes/Clymer manual on the bike. The DT's were a very hardy two stroke!

You have yourself a bargain!!

I still have a 1980 Yamaha DT175. The oil reservor is behind the right side panel. The speedometer has a green light (neutral) and a red light which warns you when the oil reservor is low. Like NH Kevin said, be sure to buy "injector" oil. Bel-Ray has one "Si-7" (which is kind of pricy) and Yamalube makes a good injector oil refered to as "2-S".

The DT's are very durable. I have had no problems with mine after 14,500 miles.

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